changeset 920:386ef449df51 feature/d1_staggered

Merge with default.
author Martin Almquist <malmquist@stanford.edu>
date Wed, 28 Nov 2018 17:35:19 -0800
parents c70131daaa6e (diff) 306f5b3cd7bc (current diff)
children 9c74d96fc9e2
files +multiblock/DiffOp.m +scheme/Elastic2dVariable.m +scheme/Wave.m +scheme/bcSetup.m .hgtags
diffstat 32 files changed, 3569 insertions(+), 97 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+grid/Staggered1d.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,99 @@
+classdef Staggered1d < grid.Structured
+    properties 
+        grids  % Cell array of grids
+        Ngrids % Number of grids
+        h      % Interior grid spacing
+        d      % Number of dimensions
+    end
+
+    methods
+
+        % Accepts multiple grids and combines them into a staggered grid
+        function obj = Staggered1d(varargin)
+
+            obj.d = 1;
+
+            obj.Ngrids = length(varargin);
+            obj.grids = cell(obj.Ngrids, 1);
+            for i = 1:obj.Ngrids
+                obj.grids{i} = varargin{i};
+            end
+
+            obj.h = [];
+        end
+
+        % N returns the total number of points
+        function o = N(obj)
+            o = 0;
+            for i=1:obj.Ngrids
+                o = o+obj.grids{i}.size();
+            end
+        end
+
+        % D returns the spatial dimension of the grid
+        function o = D(obj)
+            o = obj.d;
+        end
+
+        % size returns the number of points on the primal grid
+        function m = size(obj)
+            m = obj.grids{1}.size();
+        end
+
+        % points returns an n x 1 vector containing the coordinates for all points.
+        function X = points(obj)
+            X = [];
+            for i = 1:obj.Ngrids
+                X = [X; obj.grids{i}.points()];
+            end
+        end
+
+        % matrices returns a cell array with coordinates in matrix form.
+        % For 2d case these will have to be transposed to work with plotting routines.
+        function X = matrices(obj)
+
+            % There is no 1d matrix data type in matlab, handle special case
+            X{1} = reshape(obj.points(), [obj.m 1]);
+
+        end
+
+        function h = scaling(obj)
+            if isempty(obj.h)
+                error('grid:Staggered1d:NoScalingSet', 'No scaling set')
+            end
+
+            h = obj.h;
+        end
+
+        % Restricts the grid function gf on obj to the subgrid g.
+        % Only works for even multiples
+        function gf = restrictFunc(obj, gf, g)
+            error('grid:Staggered1d:NotImplemented','This method does not exist yet')
+        end
+
+        % Projects the grid function gf on obj to the grid g.
+        function gf = projectFunc(obj, gf, g)
+            error('grid:Staggered1d:NotImplemented','This method does not exist yet')
+        end
+
+        % Return the names of all boundaries in this grid.
+        function bs = getBoundaryNames(obj)
+            switch obj.D()
+                case 1
+                    bs = {'l', 'r'};
+                case 2
+                    bs = {'w', 'e', 's', 'n'};
+                case 3
+                    bs = {'w', 'e', 's', 'n', 'd', 'u'};
+                otherwise
+                    error('not implemented');
+            end
+        end
+
+        % Return coordinates for the given boundary
+        function X = getBoundary(obj, name)
+            % Use boundaries of first grid
+            X = obj.grids{1}.getBoundary(name);
+        end
+    end
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+grid/blockEvalOn.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,30 @@
+% Useful for evaulating forcing functions with different functional expressions for each block
+% f: cell array of function handles fi
+% f_i = f_i(x1,y,...,t)
+% t: time point. If not specified, it is assumed that the functions take only spatial arguments.
+function gf = blockEvalOn(g, f, t)
+default_arg('t',[]);
+
+grids = g.grids;
+nBlocks = length(grids);
+gf = cell(nBlocks,1);
+
+if isempty(t)
+	for i = 1:nBlocks
+		grid.evalOn(grids{i}, f{i} );
+	end
+else
+	dim = nargin(f{1}) - 1;
+	for i = 1:nBlocks
+		switch dim
+		case 1
+			gf{i} = grid.evalOn(grids{i}, @(x)f{i}(x,t) );
+		case 2
+			gf{i} = grid.evalOn(grids{i}, @(x,y)f{i}(x,y,t) );
+		case 3
+			gf{i} = grid.evalOn(grids{i}, @(x,y,z)f{i}(x,y,z,t) );
+		end
+	end
+end
+
+gf = blockmatrix.toMatrix(gf);
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+grid/primalDual1D.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,30 @@
+% Creates a 1D staggered grid of dimension length(m).
+% over the interval xlims
+% Primal grid: equidistant with m points.
+% Dual grid: m + 1 points, h/2 spacing first point.
+% Examples
+%   g = grid.primal_dual_1D(m, xlim)
+%   g = grid.primal_dual_1D(11, {0,1})
+function [g_primal, g_dual] = primalDual1D(m, xlims)
+
+    if ~iscell(xlims) || numel(xlims) ~= 2
+        error('grid:primalDual1D:InvalidLimits','The limits should be cell arrays with 2 elements.');
+    end
+
+    if xlims{1} > xlims{2}
+        error('grid:primalDual1D:InvalidLimits','The elements of the limit must be increasing.');
+    end
+
+    xl = xlims{1};
+    xr = xlims{2};
+    h = (xr-xl)/(m-1);
+
+    % Primal grid
+    g_primal = grid.equidistant(m, xlims);
+    g_primal.h = h;
+
+    % Dual grid
+    x = [xl; linspace(xl+h/2, xr-h/2, m-1)'; xr];
+    g_dual = grid.Cartesian(x);
+    g_dual.h = h;
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+grid/primalDual1DTest.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,32 @@
+function tests = primalDual1DTest()
+    tests = functiontests(localfunctions);
+end
+
+
+function testErrorInvalidLimits(testCase)
+     in  = {
+        {10,{1}},
+        {10,[0,1]},
+        {10,{1,0}},
+    };
+
+    for i = 1:length(in)
+        testCase.verifyError(@()grid.primalDual1D(in{i}{:}),'grid:primalDual1D:InvalidLimits',sprintf('in(%d) = %s',i,toString(in{i})));
+    end
+end
+
+function testCompiles(testCase)
+    in  = {
+        {5, {0,1}},
+    };
+
+    out = {
+        {[0; 0.25; 0.5; 0.75; 1], [0; 0.125; 0.375; 0.625; 0.875; 1]},
+    };
+
+    for i = 1:length(in)
+        [gp, gd] = grid.primalDual1D(in{i}{:});
+        testCase.verifyEqual(gp.points(),out{i}{1});
+        testCase.verifyEqual(gd.points(),out{i}{2});
+    end
+end
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+multiblock/+domain/Line.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,153 @@
+classdef Line < multiblock.Definition
+    properties
+
+    xlims
+    blockNames % Cell array of block labels
+    nBlocks
+    connections % Cell array specifying connections between blocks
+    boundaryGroups % Structure of boundaryGroups
+
+    end
+
+
+    methods
+        % Creates a divided line
+        % x is a vector of boundary and interface positions.
+        % blockNames: cell array of labels. The id is default.
+        function obj = Line(x,blockNames)
+            default_arg('blockNames',[]);
+
+            N = length(x)-1; % number of blocks in the x direction.
+
+            if ~issorted(x)
+                error('The elements of x seem to be in the wrong order');
+            end
+
+            % Dimensions of blocks and number of points
+            blockTi = cell(N,1);
+            xlims = cell(N,1);
+            for i = 1:N
+                xlims{i} = {x(i), x(i+1)};
+            end
+
+            % Interface couplings
+            conn = cell(N,N);
+            for i = 1:N
+                conn{i,i+1} = {'r','l'};
+            end
+
+            % Block names (id number as default)
+            if isempty(blockNames)
+                obj.blockNames = cell(1, N);
+                for i = 1:N
+                    obj.blockNames{i} = sprintf('%d', i);
+                end
+            else
+                assert(length(blockNames) == N);
+                obj.blockNames = blockNames;
+            end
+            nBlocks = N;
+
+            % Boundary groups
+            boundaryGroups = struct();
+            L = { {1, 'l'} };
+            R = { {N, 'r'} };
+            boundaryGroups.L = multiblock.BoundaryGroup(L);
+            boundaryGroups.R = multiblock.BoundaryGroup(R);
+            boundaryGroups.all = multiblock.BoundaryGroup([L,R]);
+
+            obj.connections = conn;
+            obj.nBlocks = nBlocks;
+            obj.boundaryGroups = boundaryGroups;
+            obj.xlims = xlims;
+
+        end
+
+
+        % Returns a multiblock.Grid given some parameters
+        % ms: cell array of m values 
+        % For same m in every block, just input one scalar.
+        function g = getGrid(obj, ms, varargin)
+
+            default_arg('ms',21)
+
+            % Extend ms if input is a single scalar
+            if (numel(ms) == 1) && ~iscell(ms)
+                m = ms;
+                ms = cell(1,obj.nBlocks);
+                for i = 1:obj.nBlocks
+                    ms{i} = m;
+                end
+            end
+
+            grids = cell(1, obj.nBlocks);
+            for i = 1:obj.nBlocks
+                grids{i} = grid.equidistant(ms{i}, obj.xlims{i}, obj.ylims{i});
+            end
+
+            g = multiblock.Grid(grids, obj.connections, obj.boundaryGroups);
+        end
+
+        % Returns a multiblock.Grid given some parameters
+        % ms: cell array of m values 
+        % For same m in every block, just input one scalar.
+        function g = getStaggeredGrid(obj, ms, varargin)
+
+            default_arg('ms',21)
+
+            % Extend ms if input is a single scalar
+            if (numel(ms) == 1) && ~iscell(ms)
+                m = ms;
+                ms = cell(1,obj.nBlocks);
+                for i = 1:obj.nBlocks
+                    ms{i} = m;
+                end
+            end
+
+            grids = cell(1, obj.nBlocks);
+            for i = 1:obj.nBlocks
+                [g_primal, g_dual] = grid.primalDual1D(ms{i}, obj.xlims{i});
+                grids{i} = grid.Staggered1d(g_primal, g_dual);
+            end
+
+            g = multiblock.Grid(grids, obj.connections, obj.boundaryGroups);
+        end
+
+        % label is the type of label used for plotting,
+        % default is block name, 'id' show the index for each block.
+        function show(obj, label)
+            default_arg('label', 'name')
+
+            m = 10;
+            figure
+            for i = 1:obj.nBlocks
+               x = linspace(obj.xlims{i}{1}, obj.xlims{i}{2}, m);
+               y = 0*x + 0.05* ( (-1)^i + 1 ) ;
+               plot(x,y,'+');
+               hold on 
+            end
+            hold off
+
+            switch label
+                case 'name'
+                    labels = obj.blockNames;
+                case 'id'
+                    labels = {};
+                    for i = 1:obj.nBlocks
+                        labels{i} = num2str(i);
+                    end
+                otherwise
+                    axis equal
+                    return
+            end
+
+            legend(labels)
+            axis equal
+        end
+
+        % Returns the grid size of each block in a cell array
+        % The input parameters are determined by the subclass
+        function ms = getGridSizes(obj, varargin)
+        end
+    end
+end
--- a/+multiblock/DiffOp.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+multiblock/DiffOp.m	Wed Nov 28 17:35:19 2018 -0800
@@ -148,6 +148,28 @@
             end
         end
 
+        % Get a boundary operator specified by opName for the given boundary/BoundaryGroup
+        function op = getBoundaryOperatorWrapper(obj, opName, boundary)
+            switch class(boundary)
+                case 'cell'
+                    blockId = boundary{1};
+                    localOp = obj.diffOps{blockId}.get_boundary_operator(opName, boundary{2});
+
+                    div = {obj.blockmatrixDiv{1}, size(localOp,2)};
+                    blockOp = blockmatrix.zero(div);
+                    blockOp{blockId,1} = localOp;
+                    op = blockmatrix.toMatrix(blockOp);
+                    return
+                case 'multiblock.BoundaryGroup'
+                    op = sparse(size(obj.D,1),0);
+                    for i = 1:length(boundary)
+                        op = [op, obj.getBoundaryOperatorWrapper(opName, boundary{i})];
+                    end
+                otherwise
+                    error('Unknown boundary indentifier')
+            end
+        end
+
         function op = getBoundaryQuadrature(obj, boundary)
             opName = 'H';
             switch class(boundary)
--- a/+multiblock/Grid.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+multiblock/Grid.m	Wed Nov 28 17:35:19 2018 -0800
@@ -132,6 +132,27 @@
 
         end
 
+        % Pads a grid function that lives on a subgrid with
+        % zeros and gives it the size that mathces obj.
+        function gf = expandFunc(obj, gfSub, subGridId)
+            nComponents = length(gfSub)/obj.grids{subGridId}.N();
+            nBlocks = numel(obj.grids);
+
+            % Create sparse block matrix
+            gfs = cell(nBlocks,1);
+            for i = 1:nBlocks
+                N = obj.grids{i}.N()*nComponents;
+                gfs{i} = sparse(N, 1);
+            end
+
+            % Insert local gf
+            gfs{subGridId} = gfSub;
+
+            % Convert cell to vector
+            gf = blockmatrix.toMatrix(gfs);
+
+        end
+
         % Find all non interface boundaries of all blocks.
         % Return their grid.boundaryIdentifiers in a cell array.
         function bs = getBoundaryNames(obj)
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_2.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,71 @@
+function [xp, xm, Pp, Pm, Qp, Qm] = d1_staggered_2(n, L)
+% [xp, xm, Pp, Pm, Qp, Qm] = sbp_staggered_2(n, L)
+% Input arguments:
+% n : number of grid points: n on xp grid and n+1 on xm grid
+% L : interval length
+
+h = L/(n-1);
+
+n = n - 1;
+assert(n >= 3, 'Not enough grid points');  
+
+qm20 = -1/4;
+qm01 = 1/2;
+qp11 = -1/4;
+qm11 = 1/4;
+qp02 = 1/4;
+pp0 = 1/2;
+pm1 = 1/4;
+qm00 = -1/2;
+qp10 = -1/2;
+qp12 = 3/4;
+qp00 = -1/2;
+qm21 = -3/4;
+pp1 = 1;
+qp01 = 1/4;
+pm0 = 1/2;
+pm2 = 5/4;
+qm10 = -1/4;
+
+% Q+ and Q-, top-left corner
+QpL = [...
+qp00, qp01, qp02;
+ qp10, qp11, qp12
+];
+QmL = [...
+qm00, qm01;
+ qm10, qm11;
+ qm20, qm21
+];
+
+% Q+ and Q-
+b = 2;
+w = b; 
+s = [-1, 1]';  
+Qp = spdiags(repmat(-s(end:-1:1)',[n+2 1]), -(w/2-1):w/2, n+2, n+2); 
+Qm = spdiags(repmat(s(:)',[n+2 1]), -(w/2-1)-1:w/2-1, n+2, n+2);
+Qp(end,:) = [];
+Qm(:,end) = [];
+
+% Add SBP boundary closures
+Qp(1:b,1:b+1) = QpL;
+Qp(end-b+1:end,end-b:end) = -fliplr(flipud(QpL));
+Qm(1:b+1,1:b) = QmL;
+Qm(end-b:end,end-b+1:end) = -fliplr(flipud(QmL));
+
+% P+ and P-
+Pp = ones(n+1,1);
+Pm = ones(n+2,1);
+
+Pp(1:b) = [pp0,  pp1]; 
+Pp(end-b+1:end) = Pp(b:-1:1);
+Pm(1:b+1) = [pm0,  pm1,  pm2];
+Pm(end-b:end) = Pm(b+1:-1:1);
+Pp = spdiags(Pp,0,n+1,n+1);
+Pm = spdiags(Pm,0,n+2,n+2);
+
+Pp = h*Pp;
+Pm = h*Pm;
+
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';  
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_4.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,58 @@
+function [xp, xm, Pp, Pm, Qp, Qm] = d1_staggered_4(n, L)
+% [xp, xm, Pp, Pm, Qp, Qm] = sbp_staggered_4(n, L)
+% Input arguments:
+% n : number of grid points: n on xp grid and n+1 on xm grid
+% L : interval length
+
+h = L/(n-1);
+
+n = n - 1;
+assert(n >= 7, 'Not enough grid points');  
+
+% Q+ and Q-, top-left corner
+QpL = [...
+-323/378, 2783/3072, -1085/27648, -17/9216, -667/64512;
+ -5/21, -847/1024, 1085/1024, -37/1024, 899/21504;
+ 5/42, -121/1024, -1085/1024, 3575/3072, -753/7168;
+ -5/189, 121/3072, 1085/27648, -10759/9216, 74635/64512
+];
+QmL = [...
+-55/378, 5/21, -5/42, 5/189;
+ -2783/3072, 847/1024, 121/1024, -121/3072;
+ 1085/27648, -1085/1024, 1085/1024, -1085/27648;
+ 17/9216, 37/1024, -3575/3072, 10759/9216;
+ 667/64512, -899/21504, 753/7168, -74635/64512
+];
+
+% Q+ and Q-
+w = 4; 
+s = [ 1/24,  -9/8,  9/8,  -1/24];  
+Qp = spdiags(repmat(-s(end:-1:1),[n+2 1]), -(w/2-1):w/2, n+2, n+2); 
+Qm = spdiags(repmat(s(:)',[n+2 1]), -(w/2-1)-1:w/2-1, n+2, n+2);
+Qp(end,:) = [];
+Qm(:,end) = [];
+
+% Add SBP boundary closures
+bp = 4; 
+bm = 5;
+Qp(1:bp,1:bm) = double(QpL);
+Qp(end-bp+1:end,end-bm+1:end) = -fliplr(flipud(QpL));
+Qm(1:bm,1:bp) = double(QmL);
+Qm(end-bm+1:end,end-bp+1:end) = -fliplr(flipud(QmL));
+
+% P+ and P-
+Pp = ones(n+1,1);
+Pm = ones(n+2,1);
+
+Pp(1:bp) = [407/1152,  473/384,  343/384,  1177/1152]; 
+Pp(end-bp+1:end) = Pp(bp:-1:1);
+Pm(1:bm) = [5/63,  121/128,  1085/1152,  401/384,  2659/2688];
+Pm(end-bm+1:end) = Pm(bm:-1:1);
+Pp = spdiags(Pp,0,n+1,n+1);
+Pm = spdiags(Pm,0,n+2,n+2);
+
+Pp = h*Pp;
+Pm = h*Pm;
+
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';  
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_6.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,103 @@
+function [xp, xm, Pp, Pm, Qp, Qm] = d1_staggered_6(n, L)
+% [xp, xm, Pp, Pm, Qp, Qm] = sbp_staggered_6(n, L)
+% Input arguments:
+% n : number of grid points: n on xp grid and n+1 on xm grid
+% L : interval length
+
+h = L/(n-1);
+
+n = n - 1;
+assert(n >= 9, 'Not enough grid points');  
+
+% Coefficients determined such that the SBP property is satisfied
+qp44 = -144662434693018337/131093333881896960;
+pp3 = 793/720;
+qp22 = -729260819980499/780317463582720;
+pm5 = 1262401/1244160;
+pp4 = 157/160;
+qp03 = -1056618403248889/17835827739033600;
+qp32 = 17518644727427/2340952390748160;
+pm4 = 224201/241920;
+pm2 = 90101/103680;
+qp40 = -572605772036807/27311111225395200;
+qp30 = 3572646778087103/61450000257139200;
+pm3 = 26369/23040;
+qp41 = 935926732952051/29964190601576448;
+qp02 = -67953322736279/2340952390748160;
+pp0 = 95/288;
+qp01 = 143647626126052207/149820953007882240;
+pp1 = 317/240;
+qp12 = 444281115722813/468190478149632;
+qp25 = 312883915256963/24970158834647040;
+qp11 = -36400588465707331/37455238251970560;
+qp20 = -137012145866261/13655555612697600;
+qp10 = -1008199398207353/6827777806348800;
+qp15 = -1088192686015471/37455238251970560;
+qp04 = -239061311631881/131093333881896960;
+qp35 = -2480203967217637/112365714755911680;
+qp21 = 1658590350384343/24970158834647040;
+qp05 = 4843362440877649/449462859023646720;
+qp24 = -372310079307409/4369777796063232;
+qp33 = -4809914536549211/4458956934758400;
+qp23 = 2826535075774271/2972637956505600;
+qp42 = 4202889834071/585238097687040;
+qp14 = 492703999899311/32773333470474240;
+pm1 = 133801/138240;
+qp34 = 36544940032227659/32773333470474240;
+qp00 = -216175739231516543/245800001028556800;
+qp43 = 128340370711031/17835827739033600;
+qp13 = 823082791653949/4458956934758400;
+pm0 = 5251/68040;
+pp2 = 23/30;
+qp45 = 170687698457070187/149820953007882240;
+qp31 = -3169112007572299/37455238251970560;
+
+% Q+ and Q-, top-left corner
+QpL = [...
+-216175739231516543/245800001028556800, 143647626126052207/149820953007882240, -67953322736279/2340952390748160, -1056618403248889/17835827739033600, -239061311631881/131093333881896960, 4843362440877649/449462859023646720;
+ -1008199398207353/6827777806348800, -36400588465707331/37455238251970560, 444281115722813/468190478149632, 823082791653949/4458956934758400, 492703999899311/32773333470474240, -1088192686015471/37455238251970560;
+ -137012145866261/13655555612697600, 1658590350384343/24970158834647040, -729260819980499/780317463582720, 2826535075774271/2972637956505600, -372310079307409/4369777796063232, 312883915256963/24970158834647040;
+ 3572646778087103/61450000257139200, -3169112007572299/37455238251970560, 17518644727427/2340952390748160, -4809914536549211/4458956934758400, 36544940032227659/32773333470474240, -2480203967217637/112365714755911680;
+ -572605772036807/27311111225395200, 935926732952051/29964190601576448, 4202889834071/585238097687040, 128340370711031/17835827739033600, -144662434693018337/131093333881896960, 170687698457070187/149820953007882240
+];
+QmL = [...
+-29624261797040257/245800001028556800, 1008199398207353/6827777806348800, 137012145866261/13655555612697600, -3572646778087103/61450000257139200, 572605772036807/27311111225395200;
+ -143647626126052207/149820953007882240, 36400588465707331/37455238251970560, -1658590350384343/24970158834647040, 3169112007572299/37455238251970560, -935926732952051/29964190601576448;
+ 67953322736279/2340952390748160, -444281115722813/468190478149632, 729260819980499/780317463582720, -17518644727427/2340952390748160, -4202889834071/585238097687040;
+ 1056618403248889/17835827739033600, -823082791653949/4458956934758400, -2826535075774271/2972637956505600, 4809914536549211/4458956934758400, -128340370711031/17835827739033600;
+ 239061311631881/131093333881896960, -492703999899311/32773333470474240, 372310079307409/4369777796063232, -36544940032227659/32773333470474240, 144662434693018337/131093333881896960;
+ -4843362440877649/449462859023646720, 1088192686015471/37455238251970560, -312883915256963/24970158834647040, 2480203967217637/112365714755911680, -170687698457070187/149820953007882240
+];
+
+% Q+ and Q-
+w = 6; 
+s = [ -3/640,  25/384,  -75/64,  75/64,  -25/384,  3/640];  
+Qp = spdiags(repmat(-s(end:-1:1),[n+2 1]), -(w/2-1):w/2, n+2, n+2); 
+Qm = spdiags(repmat(s(:)',[n+2 1]), -(w/2-1)-1:w/2-1, n+2, n+2);
+Qp(end,:) = [];
+Qm(:,end) = [];
+
+% Add SBP boundary closures
+bp = 5;
+bm = 6;
+Qp(1:bp,1:bm) = double(QpL);
+Qp(end-bp+1:end,end-bm+1:end) = -fliplr(flipud(QpL));
+Qm(1:bm,1:bp) = double(QmL);
+Qm(end-bm+1:end,end-bp+1:end) = -fliplr(flipud(QmL));
+
+% P+ and P-
+Pp = ones(n+1,1);
+Pm = ones(n+2,1);
+
+Pp(1:bp) = [95/288,  317/240,  23/30,  793/720,  157/160]; 
+Pp(end-bp+1:end) = Pp(bp:-1:1);
+Pm(1:bm) = [5251/68040,  133801/138240,  90101/103680,  26369/23040,  224201/241920,  1262401/1244160];
+Pm(end-bm+1:end) = Pm(bm:-1:1);
+Pp = spdiags(Pp,0,n+1,n+1);
+Pm = spdiags(Pm,0,n+2,n+2);
+
+Pp = h*Pp;
+Pm = h*Pm;
+
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_upwind_2.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,73 @@
+function [xp,xm,Hp,Hm,HIp,HIm,Dp,Dm,Dpp,Dpm,Dmp,Dmm] = d1_staggered_upwind_2(n,L)
+
+assert(n-1 >= 6,'Not enough grid points');  
+
+np=n;
+nm=n+1;
+h = L/(n-1);
+
+
+%H- norm
+Hm_U=[0.88829e5 / 0.599299e6 0 0; 0 0.8056187e7 / 0.9588784e7 0; 0 0 0.9700117e7 / 0.9588784e7;];
+%H+ norm
+Hp_U=[0.7489557e7 / 0.19177568e8 0 0; 0 0.1386089e7 / 0.1198598e7 0; 0 0 0.18276939e8 / 0.19177568e8;];
+% Upper part of Qpp. Notice that the B matrix is not included here.
+% Qpp+Qpp^T=S/2,Qpp+Qpm^T=0 
+Qpp_U=[-0.1e1 / 0.32e2 0.12886609e8 / 0.19177568e8 -0.1349263e7 / 0.9588784e7; -0.10489413e8 / 0.19177568e8 -0.3e1 / 0.16e2 0.16482403e8 / 0.19177568e8; 0.187491e6 / 0.2397196e7 -0.9290815e7 / 0.19177568e8 -0.11e2 / 0.32e2;];
+% Upper part of Qmp. Notice that the B matrix is not included here.
+% Qmp+Qmp^T=S/2,Qmp+Qmm^T=0 
+Qmp_U=[-0.2e1 / 0.21e2 0.12495263e8 / 0.16780372e8 -0.7520839e7 / 0.50341116e8; -0.7700871e7 / 0.16780372e8 -0.31e2 / 0.112e3 0.57771939e8 / 0.67121488e8; 0.2726447e7 / 0.50341116e8 -0.31402783e8 / 0.67121488e8 -0.113e3 / 0.336e3;];
+% The staggered + operator, upper part. Notice that the B matrix is not included here.Qp+Qm^T=0
+Qp_U=[-0.801195e6 / 0.2397196e7 0.16507959e8 / 0.19177568e8 -0.509615e6 / 0.19177568e8; -0.219745e6 / 0.1198598e7 -0.2112943e7 / 0.2397196e7 0.2552433e7 / 0.2397196e7; 0.42087e5 / 0.2397196e7 0.395585e6 / 0.19177568e8 -0.19909849e8 / 0.19177568e8;];
+Hp=spdiags(ones(np,1),0,np,np);
+Hp(1:3,1:3)=Hp_U;
+Hp(np-2:np,np-2:np)=fliplr(flipud(Hp_U));
+Hp=Hp*h;
+HIp=inv(Hp);
+
+Hm=spdiags(ones(nm,1),0,nm,nm);
+Hm(1:3,1:3)=Hm_U;
+Hm(nm-2:nm,nm-2:nm)=fliplr(flipud(Hm_U));
+Hm=Hm*h;
+HIm=inv(Hm);
+
+Qpp=spdiags(repmat([-0.3e1 / 0.8e1 -0.3e1 / 0.8e1 0.7e1 / 0.8e1 -0.1e1 / 0.8e1;],[np,1]),-1:2,np,np);
+Qpp(1:3,1:3)=Qpp_U;
+Qpp(np-2:np,np-2:np)=flipud( fliplr(Qpp_U(1:3,1:3) ) )'; 
+
+Qpm=-Qpp';
+
+Qmp=spdiags(repmat([-0.3e1 / 0.8e1 -0.3e1 / 0.8e1 0.7e1 / 0.8e1 -0.1e1 / 0.8e1;],[nm,1]),-1:2,nm,nm);
+Qmp(1:3,1:3)=Qmp_U;
+Qmp(nm-2:nm,nm-2:nm)=flipud( fliplr(Qmp_U(1:3,1:3) ) )'; 
+
+Qmm=-Qmp';
+
+
+Bpp=spalloc(np,np,2);Bpp(1,1)=-1;Bpp(np,np)=1;
+Bmp=spalloc(nm,nm,2);Bmp(1,1)=-1;Bmp(nm,nm)=1;
+
+Dpp=HIp*(Qpp+1/2*Bpp) ;
+Dpm=HIp*(Qpm+1/2*Bpp) ;
+
+
+Dmp=HIm*(Qmp+1/2*Bmp) ;
+Dmm=HIm*(Qmm+1/2*Bmp) ;
+
+
+%%% Start with the staggered
+Qp=spdiags(repmat([-1 1],[np,1]),0:1,np,nm);
+Qp(1:3,1:3)=Qp_U;
+Qp(np-2:np,nm-2:nm)=flipud( fliplr(-Qp_U(1:3,1:3) ) ); 
+Qm=-Qp';
+
+Bp=spalloc(np,nm,2);Bp(1,1)=-1;Bp(np,nm)=1;
+Bm=Bp';
+
+Dp=HIp*(Qp+1/2*Bp) ;
+
+Dm=HIm*(Qm+1/2*Bm) ;
+
+% grids
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';  
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_upwind_4.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,76 @@
+function [xp,xm,Hp,Hm,HIp,HIm,Dp,Dm,Dpp,Dpm,Dmp,Dmm] = d1_staggered_upwind_4(n,L)
+
+assert(n-1 >= 8,'Not enough grid points');  
+
+np=n;
+nm=n+1;
+h = L/(n-1);
+
+
+%H- norm
+Hm_U=[0.91e2 / 0.720e3 0 0 0; 0 0.325e3 / 0.384e3 0 0; 0 0 0.595e3 / 0.576e3 0; 0 0 0 0.1909e4 / 0.1920e4;];
+%H+ norm
+Hp_U=[0.805e3 / 0.2304e4 0 0 0; 0 0.955e3 / 0.768e3 0 0; 0 0 0.677e3 / 0.768e3 0; 0 0 0 0.2363e4 / 0.2304e4;];
+% Upper part of Qpp. Notice that the B matrix is not included here.
+% Qpp+Qpp^T=S/2,Qpp+Qpm^T=0 
+Qpp_U=[-0.11e2 / 0.1536e4 0.1493e4 / 0.2304e4 -0.571e3 / 0.4608e4 -0.13e2 / 0.768e3; -0.697e3 / 0.1152e4 -0.121e3 / 0.1536e4 0.97e2 / 0.128e3 -0.473e3 / 0.4608e4; 0.373e3 / 0.4608e4 -0.139e3 / 0.256e3 -0.319e3 / 0.1536e4 0.1999e4 / 0.2304e4; 0.1e1 / 0.32e2 -0.121e3 / 0.4608e4 -0.277e3 / 0.576e3 -0.143e3 / 0.512e3;];
+
+% Upper part of Qmp. Notice that the B matrix is not included here.
+% Qmp+Qmp^T=S/2,Qmp+Qmm^T=0 
+Qmp_U=[-0.209e3 / 0.5970e4 0.13439e5 / 0.17910e5 -0.13831e5 / 0.47760e5 0.10637e5 / 0.143280e6; -0.44351e5 / 0.71640e5 -0.20999e5 / 0.152832e6 0.230347e6 / 0.229248e6 -0.70547e5 / 0.254720e6; 0.3217e4 / 0.15920e5 -0.86513e5 / 0.114624e6 -0.15125e5 / 0.76416e5 0.1087241e7 / 0.1146240e7; -0.1375e4 / 0.28656e5 0.36117e5 / 0.254720e6 -0.655601e6 / 0.1146240e7 -0.211717e6 / 0.764160e6;];
+
+% The staggered + operator, upper part. Notice that the B matrix is not included here.Qp+Qm^T=0
+Qp_U=[-0.338527e6 / 0.1004160e7 0.4197343e7 / 0.4819968e7 0.1423e4 / 0.803328e6 -0.854837e6 / 0.24099840e8; -0.520117e6 / 0.3012480e7 -0.492581e6 / 0.535552e6 0.2476673e7 / 0.2409984e7 0.520117e6 / 0.8033280e7; -0.50999e5 / 0.3012480e7 0.117943e6 / 0.1606656e7 -0.2476673e7 / 0.2409984e7 0.2712193e7 / 0.2677760e7; 0.26819e5 / 0.1004160e7 -0.117943e6 / 0.4819968e7 -0.1423e4 / 0.803328e6 -0.26119411e8 / 0.24099840e8;];
+
+Hp=spdiags(ones(np,1),0,np,np);
+Hp(1:4,1:4)=Hp_U;
+Hp(np-3:np,np-3:np)=fliplr(flipud(Hp_U));
+Hp=Hp*h;
+HIp=inv(Hp);
+
+Hm=spdiags(ones(nm,1),0,nm,nm);
+Hm(1:4,1:4)=Hm_U;
+Hm(nm-3:nm,nm-3:nm)=fliplr(flipud(Hm_U));
+Hm=Hm*h;
+HIm=inv(Hm);
+
+Qpp=spdiags(repmat([0.7e1 / 0.128e3 -0.67e2 / 0.128e3 -0.55e2 / 0.192e3 0.61e2 / 0.64e2 -0.29e2 / 0.128e3 0.11e2 / 0.384e3;],[np,1]),-2:3,np,np);
+Qpp(1:4,1:4)=Qpp_U;
+Qpp(np-3:np,np-3:np)=flipud( fliplr(Qpp_U(1:4,1:4) ) )'; 
+
+Qpm=-Qpp';
+
+Qmp=spdiags(repmat([0.7e1 / 0.128e3 -0.67e2 / 0.128e3 -0.55e2 / 0.192e3 0.61e2 / 0.64e2 -0.29e2 / 0.128e3 0.11e2 / 0.384e3;],[nm,1]),-2:3,nm,nm);
+Qmp(1:4,1:4)=Qmp_U;
+Qmp(nm-3:nm,nm-3:nm)=flipud( fliplr(Qmp_U(1:4,1:4) ) )'; 
+
+Qmm=-Qmp';
+
+
+Bpp=spalloc(np,np,2);Bpp(1,1)=-1;Bpp(np,np)=1;
+Bmp=spalloc(nm,nm,2);Bmp(1,1)=-1;Bmp(nm,nm)=1;
+
+Dpp=HIp*(Qpp+1/2*Bpp) ;
+Dpm=HIp*(Qpm+1/2*Bpp) ;
+
+
+Dmp=HIm*(Qmp+1/2*Bmp) ;
+Dmm=HIm*(Qmm+1/2*Bmp) ;
+
+
+%%% Start with the staggered
+Qp=spdiags(repmat([1/24 -9/8 9/8 -1/24],[np,1]),-1:2,np,nm);
+Qp(1:4,1:4)=Qp_U;
+Qp(np-3:np,nm-3:nm)=flipud( fliplr(-Qp_U(1:4,1:4) ) ); 
+Qm=-Qp';
+
+Bp=spalloc(np,nm,2);Bp(1,1)=-1;Bp(np,nm)=1;
+Bm=Bp';
+
+Dp=HIp*(Qp+1/2*Bp) ;
+
+Dm=HIm*(Qm+1/2*Bm) ;
+
+% grids
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';  
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_upwind_6.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,78 @@
+function [xp,xm,Hp,Hm,HIp,HIm,Dp,Dm,Dpp,Dpm,Dmp,Dmm] = d1_staggered_upwind_6(n,L)
+
+assert(n-1 >= 12,'Not enough grid points');  
+
+np=n;
+nm=n+1;
+h = L/(n-1);
+
+bp=6; % Number of boundary points
+
+
+%H- norm
+Hm_U=[0.18373e5 / 0.136080e6 0 0 0 0 0; 0 0.228247e6 / 0.276480e6 0 0 0 0; 0 0 0.219557e6 / 0.207360e6 0 0 0; 0 0 0 0.44867e5 / 0.46080e5 0 0; 0 0 0 0 0.487757e6 / 0.483840e6 0; 0 0 0 0 0 0.2485447e7 / 0.2488320e7;];
+%H+ norm
+Hp_U=[0.174529e6 / 0.552960e6 0 0 0 0 0; 0 0.769723e6 / 0.552960e6 0 0 0 0; 0 0 0.172613e6 / 0.276480e6 0 0 0; 0 0 0 0.343867e6 / 0.276480e6 0 0; 0 0 0 0 0.503237e6 / 0.552960e6 0; 0 0 0 0 0 0.560831e6 / 0.552960e6;];
+% Upper part of Qpp. Notice that the B matrix is not included here.
+% Qpp+Qpp^T=S/2,Qpp+Qpm^T=0 
+Qpp_U=[-0.11e2 / 0.12288e5 0.3248629e7 / 0.4976640e7 -0.742121e6 / 0.9953280e7 -0.173089e6 / 0.1658880e7 0.100627e6 / 0.9953280e7 0.263e3 / 0.15552e5; -0.3212989e7 / 0.4976640e7 -0.341e3 / 0.20480e5 0.488429e6 / 0.995328e6 0.2108717e7 / 0.9953280e7 0.5623e4 / 0.829440e6 -0.468779e6 / 0.9953280e7; 0.635201e6 / 0.9953280e7 -0.2135641e7 / 0.4976640e7 -0.2233e4 / 0.30720e5 0.298757e6 / 0.497664e6 -0.2148901e7 / 0.9953280e7 0.99581e5 / 0.1658880e7; 0.184969e6 / 0.1658880e7 -0.2671829e7 / 0.9953280e7 -0.1044721e7 / 0.2488320e7 -0.4697e4 / 0.30720e5 0.882599e6 / 0.995328e6 -0.2114063e7 / 0.9953280e7; -0.118447e6 / 0.9953280e7 0.15761e5 / 0.829440e6 0.915757e6 / 0.9953280e7 -0.2923243e7 / 0.4976640e7 -0.4279e4 / 0.20480e5 0.4614511e7 / 0.4976640e7; -0.263e3 / 0.15552e5 0.422447e6 / 0.9953280e7 -0.5185e4 / 0.331776e6 0.424727e6 / 0.9953280e7 -0.570779e6 / 0.995328e6 -0.2761e4 / 0.12288e5;];
+
+% Upper part of Qmp. Notice that the B matrix is not included here.
+% Qmp+Qmp^T=S/2,Qmp+Qmm^T=0 
+Qmp_U=[-0.6660404399e10 / 0.975680535935e12 0.42802131970831759e17 / 0.60695134779444480e17 -0.27241603626152813e17 / 0.91042702169166720e17 0.148772145985039e15 / 0.1264481974571760e16 -0.386865438537449e15 / 0.30347567389722240e17 -0.739491571084877e15 / 0.182085404338333440e18; -0.40937739835891039e17 / 0.60695134779444480e17 -0.20934998251893e14 / 0.570912496455680e15 0.3069347264824655e16 / 0.3082927480860672e16 -0.531249064089227e15 / 0.1541463740430336e16 0.6343721417240047e16 / 0.107902461830123520e18 0.194756943144697e15 / 0.138731736638730240e18; 0.24212381292051773e17 / 0.91042702169166720e17 -0.13932096926615587e17 / 0.15414637404303360e17 -0.22149140293797e14 / 0.285456248227840e15 0.443549615179363e15 / 0.481707418884480e15 -0.1531771257444041e16 / 0.5994581212784640e16 0.23579222779798361e17 / 0.416195209916190720e18; -0.119651391006031e15 / 0.1264481974571760e16 0.2061363806050549e16 / 0.7707318702151680e16 -0.355212104634871e15 / 0.481707418884480e15 -0.42909037900311e14 / 0.285456248227840e15 0.25466291778687943e17 / 0.26975615457530880e17 -0.3289076301679109e16 / 0.11560978053227520e17; 0.153994229603129e15 / 0.30347567389722240e17 -0.2655886084488631e16 / 0.107902461830123520e18 0.782300684927837e15 / 0.5994581212784640e16 -0.17511430871269903e17 / 0.26975615457530880e17 -0.413193098349471e15 / 0.1998193737594880e16 0.189367309285289755e18 / 0.194224431294222336e18; 0.894580992211517e15 / 0.182085404338333440e18 -0.209441083772219e15 / 0.27746347327746048e17 -0.4946149632449393e16 / 0.416195209916190720e18 0.334964642443661e15 / 0.2890244513306880e16 -0.604469352802317407e18 / 0.971122156471111680e18 -0.128172128502407e15 / 0.570912496455680e15;];
+
+% The staggered + operator, upper part. Notice that the B matrix is not included here.Qp+Qm^T=0
+Qp_U=[-0.34660470729017653729e20 / 0.113641961250214656000e21 0.351671379135966469961e21 / 0.415604886857927884800e21 0.1819680091728191503e19 / 0.103901221714481971200e21 -0.18252344147469061739e20 / 0.346337405714939904000e21 -0.18145368485798816351e20 / 0.727308552001373798400e21 0.2627410615589536403e19 / 0.138534962285975961600e21; -0.1606450873889019037e19 / 0.7576130750014310400e19 -0.8503979509850519441e19 / 0.9235664152398397440e19 0.2208731907526094393e19 / 0.2308916038099599360e19 0.1143962309827873891e19 / 0.7696386793665331200e19 0.1263616990270014071e19 / 0.16162412266697195520e20 -0.1402288892096389187e19 / 0.27706992457195192320e20; -0.502728075208147729e18 / 0.11364196125021465600e20 0.5831273443201206481e19 / 0.41560488685792788480e20 -0.9031420599281409001e19 / 0.10390122171448197120e20 0.29977986617775158621e20 / 0.34633740571493990400e20 -0.7995649008389734663e19 / 0.72730855200137379840e20 0.728315692435313537e18 / 0.41560488685792788480e20; 0.710308100786581369e18 / 0.11364196125021465600e20 -0.2317346723533341809e19 / 0.41560488685792788480e20 -0.1357359577229545879e19 / 0.10390122171448197120e20 -0.35124499190079631261e20 / 0.34633740571493990400e20 0.81675241511291974823e20 / 0.72730855200137379840e20 0.144034831596315317e18 / 0.13853496228597596160e20; 0.13360631165154733e17 / 0.841792305557145600e18 -0.875389186128426797e18 / 0.27706992457195192320e20 0.95493318392786453e17 / 0.6926748114298798080e19 0.1714625642820850967e19 / 0.23089160380995993600e20 -0.53371483072841696197e20 / 0.48487236800091586560e20 0.30168063964639488547e20 / 0.27706992457195192320e20; -0.1943232250834614071e19 / 0.113641961250214656000e21 0.8999269402554660119e19 / 0.415604886857927884800e21 0.1242786058815312817e19 / 0.103901221714481971200e21 -0.7480218714053301461e19 / 0.346337405714939904000e21 0.28468183824757664191e20 / 0.727308552001373798400e21 -0.476082521721490837529e21 / 0.415604886857927884800e21;];
+
+Hp=spdiags(ones(np,1),0,np,np);
+Hp(1:bp,1:bp)=Hp_U;
+Hp(np-bp+1:np,np-bp+1:np)=fliplr(flipud(Hp_U));
+Hp=Hp*h;
+HIp=inv(Hp);
+
+Hm=spdiags(ones(nm,1),0,nm,nm);
+Hm(1:bp,1:bp)=Hm_U;
+Hm(nm-bp+1:nm,nm-bp+1:nm)=fliplr(flipud(Hm_U));
+Hm=Hm*h;
+HIm=inv(Hm);
+
+Qpp=spdiags(repmat([-0.157e3 / 0.15360e5 0.537e3 / 0.5120e4 -0.3147e4 / 0.5120e4 -0.231e3 / 0.1024e4 0.999e3 / 0.1024e4 -0.1461e4 / 0.5120e4 0.949e3 / 0.15360e5 -0.33e2 / 0.5120e4;],[np,1]),-3:4,np,np);
+Qpp(1:bp,1:bp)=Qpp_U;
+Qpp(np-bp+1:np,np-bp+1:np)=flipud( fliplr(Qpp_U ) )'; 
+
+Qpm=-Qpp';
+
+Qmp=spdiags(repmat([-0.157e3 / 0.15360e5 0.537e3 / 0.5120e4 -0.3147e4 / 0.5120e4 -0.231e3 / 0.1024e4 0.999e3 / 0.1024e4 -0.1461e4 / 0.5120e4 0.949e3 / 0.15360e5 -0.33e2 / 0.5120e4;],[nm,1]),-3:4,nm,nm);
+Qmp(1:bp,1:bp)=Qmp_U;
+Qmp(nm-bp+1:nm,nm-bp+1:nm)=flipud( fliplr(Qmp_U ) )'; 
+
+Qmm=-Qmp';
+
+Bpp=spalloc(np,np,2);Bpp(1,1)=-1;Bpp(np,np)=1;
+Bmp=spalloc(nm,nm,2);Bmp(1,1)=-1;Bmp(nm,nm)=1;
+
+
+Dpp=HIp*(Qpp+1/2*Bpp) ;
+Dpm=HIp*(Qpm+1/2*Bpp) ;
+
+
+Dmp=HIm*(Qmp+1/2*Bmp) ;
+Dmm=HIm*(Qmm+1/2*Bmp) ;
+
+
+%%% Start with the staggered
+Qp=spdiags(repmat([-0.3e1 / 0.640e3 0.25e2 / 0.384e3 -0.75e2 / 0.64e2 0.75e2 / 0.64e2 -0.25e2 / 0.384e3 0.3e1 / 0.640e3],[np,1]),-2:3,np,nm);
+Qp(1:bp,1:bp)=Qp_U;
+Qp(np-bp+1:np,nm-bp+1:nm)=flipud( fliplr(-Qp_U ) ); 
+Qm=-Qp';
+
+Bp=spalloc(np,nm,2);Bp(1,1)=-1;Bp(np,nm)=1;
+Bm=Bp';
+
+Dp=HIp*(Qp+1/2*Bp) ;
+
+Dm=HIm*(Qm+1/2*Bm) ;
+
+% grids
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]';  
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/+implementations/d1_staggered_upwind_8.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,82 @@
+function [xp,xm,Hp,Hm,HIp,HIm,Dp,Dm,Dpp,Dpm,Dmp,Dmm] = d1_staggered_upwind_8(n, L)
+
+assert(n-1 >= 12,'Not enough grid points');  
+
+np=n;
+nm=n+1;
+h = L/(n-1);
+
+bp=8; % Number of boundary points
+
+
+%H- norm
+Hm_U=[0.27058177e8 / 0.194594400e9 0 0 0 0 0 0 0; 0 0.378196601e9 / 0.464486400e9 0 0 0 0 0 0; 0 0 0.250683799e9 / 0.232243200e9 0 0 0 0 0; 0 0 0 0.48820787e8 / 0.51609600e8 0 0 0 0; 0 0 0 0 0.23953873e8 / 0.23224320e8 0 0 0; 0 0 0 0 0 0.55018021e8 / 0.55738368e8 0 0; 0 0 0 0 0 0 0.284772253e9 / 0.283852800e9 0; 0 0 0 0 0 0 0 0.6036097241e10 / 0.6038323200e10;];
+
+%H+ norm
+Hp_U=[0.273925927e9 / 0.928972800e9 0 0 0 0 0 0 0; 0 0.1417489391e10 / 0.928972800e9 0 0 0 0 0 0; 0 0 0.26528603e8 / 0.103219200e9 0 0 0 0 0; 0 0 0 0.66843235e8 / 0.37158912e8 0 0 0 0; 0 0 0 0 0.76542481e8 / 0.185794560e9 0 0 0; 0 0 0 0 0 0.132009637e9 / 0.103219200e9 0 0; 0 0 0 0 0 0 0.857580049e9 / 0.928972800e9 0; 0 0 0 0 0 0 0 0.937663193e9 / 0.928972800e9;];
+
+% Upper part of Qpp. Notice that the B matrix is not included here.
+% Qpp+Qpp^T=S/2,Qpp+Qpm^T=0 
+Qpp_U=[-0.5053e4 / 0.43253760e8 0.299126491231e12 / 0.442810368000e12 -0.562745123e9 / 0.8856207360e10 -0.59616938177e11 / 0.398529331200e12 -0.5489464381e10 / 0.177124147200e12 0.6994759151e10 / 0.88562073600e11 0.712609553e9 / 0.181149696000e12 -0.14167e5 / 0.998400e6; -0.74652297589e11 / 0.110702592000e12 -0.995441e6 / 0.302776320e9 0.662285893e9 / 0.2236416000e10 0.2364992837e10 / 0.5535129600e10 0.8893339297e10 / 0.49816166400e11 -0.2166314077e10 / 0.8945664000e10 -0.78813191e8 / 0.2952069120e10 0.88810243397e11 / 0.1992646656000e13; 0.16939159e8 / 0.276756480e9 -0.2302477691e10 / 0.8200192000e10 -0.197067e6 / 0.9175040e7 0.46740527413e11 / 0.88562073600e11 -0.4827794723e10 / 0.11070259200e11 0.155404199e9 / 0.1230028800e10 0.15110006581e11 / 0.295206912000e12 -0.2491856531e10 / 0.88562073600e11; 0.7568509969e10 / 0.49816166400e11 -0.19762404121e11 / 0.44281036800e11 -0.2554553593e10 / 0.5535129600e10 -0.19550057e8 / 0.302776320e9 0.145135201e9 / 0.210862080e9 0.1596117533e10 / 0.11070259200e11 0.104983477e9 / 0.3558297600e10 -0.1087937837e10 / 0.25303449600e11; 0.5282544031e10 / 0.177124147200e12 -0.131784830977e12 / 0.797058662400e12 0.8310607171e10 / 0.22140518400e11 -0.56309573e8 / 0.105431040e9 -0.36477607e8 / 0.302776320e9 0.57443289107e11 / 0.88562073600e11 -0.220576549e9 / 0.691891200e9 0.39942520697e11 / 0.398529331200e12; -0.1743516779e10 / 0.22140518400e11 0.7784403199e10 / 0.32800768000e11 -0.459036521e9 / 0.4920115200e10 -0.5749179391e10 / 0.22140518400e11 -0.562460513e9 / 0.1383782400e10 -0.1500741e7 / 0.9175040e7 0.70986504791e11 / 0.73801728000e11 -0.930160589e9 / 0.3406233600e10; -0.712609553e9 / 0.181149696000e12 0.180761e6 / 0.6589440e7 -0.18016744831e11 / 0.295206912000e12 0.18651112477e11 / 0.797058662400e12 0.7155507361e10 / 0.44281036800e11 -0.49358401541e11 / 0.73801728000e11 -0.55032223e8 / 0.302776320e9 0.38275518139e11 / 0.40255488000e11; 0.14167e5 / 0.998400e6 -0.88810243397e11 / 0.1992646656000e13 0.650307179e9 / 0.22140518400e11 0.474654619e9 / 0.16102195200e11 -0.7267828861e10 / 0.199264665600e12 0.42227833e8 / 0.425779200e9 -0.71245142351e11 / 0.110702592000e12 -0.7998899e7 / 0.43253760e8;];
+
+% Upper part of Qmp. Notice that the B matrix is not included here.
+% Qmp+Qmp^T=S/2,Qmp+Qmm^T=0 
+Qmp_U=[-0.92025012754706822244637e23 / 0.73350939131274317328275670e26 0.930302337374620084855601123690977e33 / 0.1359398284732080668181467336976000e34 -0.727851704787797291000113057457371e33 / 0.2718796569464161336362934673952000e34 0.7360201789777281105403766444579e31 / 0.90626552315472044545431155798400e32 0.13716157770579047943179985700303e32 / 0.543759313892832267272586934790400e33 -0.553550686983724599329589830113e30 / 0.21750372555713290690903477391616e32 0.39889728754596585193681401053e29 / 0.20596943708061828305779808136000e32 0.4597826214543803453588826224861e31 / 0.2718796569464161336362934673952000e34; -0.460817194517403953445488602736801e33 / 0.679699142366040334090733668488000e33 -0.2251237342833501172927156567e28 / 0.267062619272621870023659683840e30 0.190175037040902421814031988319053e33 / 0.202800676510147232549216572416000e33 -0.280264041304585424221475951435491e33 / 0.1081603608054118573595821719552000e34 -0.2948540748840639854083293613843e31 / 0.81120270604058893019686628966400e32 0.10373234521893519136055741251159e32 / 0.194688649449741343247247909519360e33 -0.391946441371315598560753809131e30 / 0.59488198442976521547770194575360e32 -0.15471439859462263133402977429037e32 / 0.6026077244872946338605292437504000e34; 0.702728186606917922841148808013121e33 / 0.2718796569464161336362934673952000e34 -0.738964213741742941634289388463587e33 / 0.811202706040588930196866289664000e33 -0.6938440904692701484464706797e28 / 0.267062619272621870023659683840e30 0.13587935221144065448123508546711e32 / 0.16900056375845602712434714368000e32 -0.398581023027193812136121833051e30 / 0.3244810824162355720787465158656e31 -0.4390487184318690815376655433561e31 / 0.486721623624353358118119773798400e33 0.39375020562052974775725982794643e32 / 0.5948819844297652154777019457536000e34 -0.337431206994896862016299739723e30 / 0.1054563517852765609255926176563200e34; -0.1626484714285090813572964936931e31 / 0.22656638078868011136357788949600e32 0.247081446636583523913555235517491e33 / 0.1081603608054118573595821719552000e34 -0.98606689532786656855690277893813e32 / 0.135200451006764821699477714944000e33 -0.54412910204947725598668603049e29 / 0.801187857817865610070979051520e30 0.44527159063104584858762191285733e32 / 0.54080180402705928679791085977600e32 -0.4170461618635408764831166558231e31 / 0.18541776138070604118785515192320e32 0.2733053052508781643445069010989e31 / 0.55081665224978260692379809792000e32 -0.62697761224771731704532896739409e32 / 0.7030423452351770728372841177088000e34; -0.16732447706243527499842078942603e32 / 0.543759313892832267272586934790400e33 0.166114324967929244010272382781e30 / 0.2897152521573531893560236748800e31 0.45101984053799299547057123965e29 / 0.811202706040588930196866289664e30 -0.17968772701532140224971787578029e32 / 0.27040090201352964339895542988800e32 -0.48635228792591105226576208151e29 / 0.400593928908932805035489525760e30 0.89480251714879473157102672858403e32 / 0.97344324724870671623623954759680e32 -0.42143863277048975845235502012773e32 / 0.148720496107441303869425486438400e33 0.4389611982769118812600028148913e31 / 0.52728175892638280462796308828160e32; 0.590475930631333482244268674627e30 / 0.21750372555713290690903477391616e32 -0.1702402353852012839500776925027e31 / 0.27812664207105906178178272788480e32 0.5538920825569170589993365115709e31 / 0.121680405906088339529529943449600e33 0.13866428236712167588433125984777e32 / 0.129792432966494228831498606346240e33 -0.16470253483258635888811378530287e32 / 0.24336081181217667905905988689920e32 -0.391812951622286986994545412081e30 / 0.2403563573453596830212937154560e31 0.345131812155051195787190432571781e33 / 0.356929190657859129286621167452160e33 -0.8126635967231661246920267342728147e34 / 0.25309524428466374622142228237516800e35; -0.88170259036818455465427409231e29 / 0.41193887416123656611559616272000e32 0.943459254925453305858100463659e30 / 0.118976396885953043095540389150720e33 -0.104249970715879362499981962934393e33 / 0.5948819844297652154777019457536000e34 0.78160374875076232344526852587e29 / 0.18360555074992753564126603264000e32 0.37536035579237342566706229296521e32 / 0.297440992214882607738850972876800e33 -0.240812609144054591374890622842541e33 / 0.356929190657859129286621167452160e33 -0.145390363516271219220036634153e30 / 0.801187857817865610070979051520e30 0.38093040928245760105862644889779897e35 / 0.38667328987934739006050626473984000e35; -0.4596580943680048141920105029111e31 / 0.2718796569464161336362934673952000e34 0.15262190991038620305994595494037e32 / 0.6026077244872946338605292437504000e34 0.1782508142749448850000523441843e31 / 0.1054563517852765609255926176563200e34 -0.33510338065544202178903991034341e32 / 0.7030423452351770728372841177088000e34 -0.8226959851063633384855147175189e31 / 0.421825407141106243702370470625280e33 0.3729744974003821244717412110773747e34 / 0.25309524428466374622142228237516800e35 -0.6554525408845613610278033864711443e34 / 0.9666832246983684751512656618496000e34 -0.49383212966905764275823531781e29 / 0.267062619272621870023659683840e30;];
+
+% The staggered + operator, upper part. Notice that the B matrix is not included here.Qp+Qm^T=0
+Qp_U=[-0.6661444046602902130086192779621746771e37 / 0.23342839720855518078613888837079040000e38 0.12367666586033683088530161144944922123649e41 / 0.14797137255429936031548004199961722880000e41 0.4395151478839780503265910147432452357e37 / 0.186518536833150454179176523528929280000e39 -0.87963490365651280757669626389462038003e38 / 0.1345194295948176002868000381814702080000e40 -0.224187853266917333808369723332131873619e39 / 0.5178998039400477611041801469986603008000e40 0.55314264508663245255306547445101748003e38 / 0.2959427451085987206309600839992344576000e40 0.232303691019191510116997121080032335473e39 / 0.7398568627714968015774002099980861440000e40 -0.2816079756494683118054172509551114287e37 / 0.182680706857159704093185237036564480000e39; -0.10353150194859080046224306922028068797e38 / 0.43350988053017390717425793554575360000e38 -0.41810120772068966379630018024826564868789e41 / 0.44391411766289808094644012599885168640000e41 0.14548989645937048285445132077600344947e38 / 0.16118885899161150361163403267932160000e38 0.1353060140543056426043612771323929599939e40 / 0.6341630252327115442092001799983595520000e40 0.52584560489710238297754746193308329991e38 / 0.317081512616355772104600089999179776000e39 -0.322880558646947920788817445027309369183e39 / 0.8878282353257961618928802519977033728000e40 -0.2523050363123545986203815545725359199053e40 / 0.22195705883144904047322006299942584320000e41 0.2171073153815036601208579021528549178587e40 / 0.44391411766289808094644012599885168640000e41; -0.891108828407068615176254357157902263e36 / 0.14450329351005796905808597851525120000e38 0.9207480733237809022786174965361787199767e40 / 0.44391411766289808094644012599885168640000e41 -0.42541158717297365539935073107511004261e38 / 0.62172845611050151393058841176309760000e38 0.3752589973871193536179209598104238527889e40 / 0.4932379085143312010516001399987240960000e40 -0.503978909830206767329311700636686423011e39 / 0.2219570588314490404732200629994258432000e40 -0.25729240076595732139825342259542295873e38 / 0.328825272342887467367733426665816064000e39 0.283553624900223723890865927423934504751e39 / 0.2466189542571656005258000699993620480000e40 -0.129077863120107719239717930927898530811e39 / 0.4035582887844528008604001145444106240000e40; 0.150348887575956035991597139943595613e36 / 0.2000814833216187263881190471749632000e37 -0.20271017027971837857434511014725441049e38 / 0.422775350155141029472800119998906368000e39 -0.28593401740189393456434271848012721991e38 / 0.87041983855470211950282377646833664000e38 -0.3107901953269564253446821657614993689969e40 / 0.2959427451085987206309600839992344576000e40 0.163990240717967340033770840655582198979e39 / 0.147971372554299360315480041999617228800e39 0.1282390462809880153203810439898877805771e40 / 0.5326969411954776971357281511986220236800e40 0.55264142141446425784998699697993554089e38 / 0.1479713725542993603154800419996172288000e40 -0.11464469241412665723941542481946601159e38 / 0.328825272342887467367733426665816064000e39; 0.523088046329055388999216632374482217e36 / 0.8670197610603478143485158710915072000e37 -0.1060078188350823496391913491020744512571e40 / 0.8878282353257961618928802519977033728000e40 0.2489758378222482566046953325470732791e37 / 0.87041983855470211950282377646833664000e38 0.2223322627542429729644405110485179851147e40 / 0.8878282353257961618928802519977033728000e40 -0.405229856535104846314030690968355556777e39 / 0.443914117662898080946440125998851686400e39 0.1490365162783652350291746570529147907183e40 / 0.1775656470651592323785760503995406745600e40 -0.768972334347761129534143069144613163467e39 / 0.4439141176628980809464401259988516864000e40 0.34866718651627637034229483614924933299e38 / 0.1268326050465423088418400359996719104000e40; -0.522920230014765612739540250860177277e36 / 0.14450329351005796905808597851525120000e38 0.1453599225900263767517831305438030179313e40 / 0.44391411766289808094644012599885168640000e41 0.39466073050115777575909309244731209107e38 / 0.435209919277351059751411888234168320000e39 -0.501532616891797921922210650058733239369e39 / 0.4932379085143312010516001399987240960000e40 -0.276688880738967796756224778348832938429e39 / 0.2219570588314490404732200629994258432000e40 -0.346414321340583244146983258114429082007e39 / 0.328825272342887467367733426665816064000e39 0.12835585968364300662881260070481636919e38 / 0.10676145205937904784666669696942080000e38 -0.823464330534329517579044232163467356639e39 / 0.44391411766289808094644012599885168640000e41; -0.52802811745049309885720368328150617e35 / 0.1688999534533145092886719229399040000e37 0.306081878756402097710283710502974342821e39 / 0.4932379085143312010516001399987240960000e40 -0.43281676756908448328630499995327205907e38 / 0.1305629757832053179254235664702504960000e40 -0.136777517026276610492513752852976312597e39 / 0.4932379085143312010516001399987240960000e40 0.7290267185112688983569547959866321207e37 / 0.246618954257165600525800069999362048000e39 0.351639553804386998900032061955116226307e39 / 0.3804978151396269265255201079990157312000e40 -0.2840607921448362125113163437018746783083e40 / 0.2466189542571656005258000699993620480000e40 0.1859197240206073478058984196606793676119e40 / 0.1644126361714437336838667133329080320000e40; 0.5412884950805861225701675068383948563e37 / 0.303456916371121735021980554882027520000e39 -0.1279848124286614098666833963684894093627e40 / 0.44391411766289808094644012599885168640000e41 0.17218770500911534891873213313315117e35 / 0.39564538116122823613764717112197120000e38 0.904771800018341402297740826650985365019e39 / 0.44391411766289808094644012599885168640000e41 0.65377500469171784914136353007658339737e38 / 0.15536994118201432833125404409959809024000e41 -0.211014619053462658139013021424372225649e39 / 0.8878282353257961618928802519977033728000e40 0.195325945159072852492812627815477159003e39 / 0.3170815126163557721046000899991797760000e40 -0.52260858238454846311625894178508086247499e41 / 0.44391411766289808094644012599885168640000e41;];
+
+Hp=spdiags(ones(np,1),0,np,np);
+Hp(1:bp,1:bp)=Hp_U;
+Hp(np-bp+1:np,np-bp+1:np)=fliplr(flipud(Hp_U));
+Hp=Hp*h;
+HIp=inv(Hp);
+
+Hm=spdiags(ones(nm,1),0,nm,nm);
+Hm(1:bp,1:bp)=Hm_U;
+Hm(nm-bp+1:nm,nm-bp+1:nm)=fliplr(flipud(Hm_U));
+Hm=Hm*h;
+HIm=inv(Hm);
+
+tt=[0.1447e4 / 0.688128e6 -0.17119e5 / 0.688128e6 0.8437e4 / 0.57344e5 -0.5543e4 / 0.8192e4 -0.15159e5 / 0.81920e5 0.16139e5 / 0.16384e5 -0.2649e4 / 0.8192e4 0.15649e5 / 0.172032e6 -0.3851e4 / 0.229376e6 0.5053e4 / 0.3440640e7;];
+
+Qpp=spdiags(repmat(tt,[np,1]),-4:5,np,np);
+Qpp(1:bp,1:bp)=Qpp_U;
+Qpp(np-bp+1:np,np-bp+1:np)=flipud( fliplr(Qpp_U ) )'; 
+
+Qpm=-Qpp';
+
+Qmp=spdiags(repmat(tt,[nm,1]),-4:5,nm,nm);
+Qmp(1:bp,1:bp)=Qmp_U;
+Qmp(nm-bp+1:nm,nm-bp+1:nm)=flipud( fliplr(Qmp_U ) )'; 
+
+Qmm=-Qmp';
+
+
+Bpp=spalloc(np,np,2);Bpp(1,1)=-1;Bpp(np,np)=1;
+Bmp=spalloc(nm,nm,2);Bmp(1,1)=-1;Bmp(nm,nm)=1;
+
+Dpp=HIp*(Qpp+1/2*Bpp) ;
+Dpm=HIp*(Qpm+1/2*Bpp) ;
+
+
+Dmp=HIm*(Qmp+1/2*Bmp) ;
+Dmm=HIm*(Qmm+1/2*Bmp) ;
+
+
+%%% Start with the staggered
+Qp=spdiags(repmat([0.5e1 / 0.7168e4 -0.49e2 / 0.5120e4 0.245e3 / 0.3072e4 -0.1225e4 / 0.1024e4 0.1225e4 / 0.1024e4 -0.245e3 / 0.3072e4 0.49e2 / 0.5120e4 -0.5e1 / 0.7168e4;],[np,1]),-3:4,np,nm);
+Qp(1:bp,1:bp)=Qp_U;
+Qp(np-bp+1:np,nm-bp+1:nm)=flipud( fliplr(-Qp_U ) ); 
+Qm=-Qp';
+
+Bp=spalloc(np,nm,2);Bp(1,1)=-1;Bp(np,nm)=1;
+Bm=Bp';
+
+Dp=HIp*(Qp+1/2*Bp) ;
+
+Dm=HIm*(Qm+1/2*Bm) ;
+
+% grids
+xp = h*[0:n]';
+xm = h*[0 1/2+0:n n]'; 
\ No newline at end of file
--- a/+sbp/+implementations/d2_variable_2.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+sbp/+implementations/d2_variable_2.m	Wed Nov 28 17:35:19 2018 -0800
@@ -27,7 +27,7 @@
     diags   = -1:1;
     stencil = [-1/2 0 1/2];
     D1 = stripeMatrix(stencil, diags, m);
-    
+
     D1(1,1)=-1;D1(1,2)=1;D1(m,m-1)=-1;D1(m,m)=1;
     D1(m,m-1)=-1;D1(m,m)=1;
     D1=D1/h;
@@ -40,7 +40,7 @@
     scheme_radius = (scheme_width-1)/2;
     r = (1+scheme_radius):(m-scheme_radius);
 
-    function D2 = D2_fun(c)
+    function [D2, B] = D2_fun(c)
 
         Mm1 = -c(r-1)/2 - c(r)/2;
         M0  =  c(r-1)/2 + c(r)   + c(r+1)/2;
@@ -54,6 +54,8 @@
         M=M/h;
 
         D2=HI*(-M-c(1)*e_l*d1_l'+c(m)*e_r*d1_r');
+        B = HI*M;
     end
     D2 = @D2_fun;
+
 end
\ No newline at end of file
--- a/+sbp/+implementations/d2_variable_4.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+sbp/+implementations/d2_variable_4.m	Wed Nov 28 17:35:19 2018 -0800
@@ -49,7 +49,7 @@
 
 
     N = m;
-    function D2 = D2_fun(c)
+    function [D2, B] = D2_fun(c)
         M = 78+(N-12)*5;
         %h = 1/(N-1);
 
@@ -131,6 +131,8 @@
             cols(40+(i-7)*5:44+(i-7)*5) = [i-2;i-1;i;i+1;i+2];
         end
         D2 = sparse(rows,cols,D2);
+
+        B = HI*( c(end)*e_r*d1_r' - c(1)*e_l*d1_l') - D2;
     end
     D2 = @D2_fun;
 end
\ No newline at end of file
--- a/+sbp/+implementations/d4_variable_6.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+sbp/+implementations/d4_variable_6.m	Wed Nov 28 17:35:19 2018 -0800
@@ -85,7 +85,7 @@
     scheme_radius = (scheme_width-1)/2;
     r = (1+scheme_radius):(m-scheme_radius);
 
-    function D2 = D2_fun(c)
+    function [D2, B] = D2_fun(c)
 
         Mm3 =  c(r-2)/0.40e2 + c(r-1)/0.40e2 - 0.11e2/0.360e3 * c(r-3) - 0.11e2/0.360e3 * c(r);
         Mm2 =  c(r-3)/0.20e2 - 0.3e1/0.10e2 * c(r-1) + c(r+1)/0.20e2 + 0.7e1/0.40e2 * c(r) + 0.7e1/0.40e2 * c(r-2);
@@ -128,6 +128,7 @@
         M=M/h;
 
         D2 = HI*(-M - c(1)*e_l*d1_l' + c(m)*e_r*d1_r');
+        B = HI*M;
     end
     D2 = @D2_fun;
 
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/D1Staggered.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,86 @@
+classdef D1Staggered < sbp.OpSet
+    properties
+        % x_primal: "primal" grid with m points. Equidistant. Called Plus grid in Ossian's paper.
+        % x_dual: "dual" grid with m+1 points. Called Minus grid in Ossian's paper.
+
+        % D1_primal takes FROM dual grid TO primal grid
+        % D1_dual takes FROM primal grid TO dual grid
+
+        D1_primal % SBP operator approximating first derivative
+        D1_dual % SBP operator approximating first derivative
+        H_primal % Norm matrix
+        H_dual % Norm matrix
+        H_primalI % H^-1
+        H_dualI % H^-1
+        e_primal_l % Left boundary operator
+        e_dual_l % Left boundary operator
+        e_primal_r % Right boundary operator
+        e_dual_r % Right boundary operator
+        m % Number of grid points.
+        m_primal % Number of grid points.
+        m_dual % Number of grid points.
+        h % Step size
+        x_primal % grid
+        x_dual % grid
+        x
+        borrowing % Struct with borrowing limits for different norm matrices
+    end
+
+    methods
+        function obj = D1Staggered(m,lim,order)
+
+          x_l = lim{1};
+          x_r = lim{2};
+          L = x_r-x_l;
+
+          m_primal = m;
+          m_dual = m+1;
+
+          switch order
+          case 2
+            [x_primal, x_dual, Pp, Pm, Qp, Qm] = sbp.implementations.d1_staggered_2(m, L);
+          case 4
+            [x_primal, x_dual, Pp, Pm, Qp, Qm] = sbp.implementations.d1_staggered_4(m, L);
+          case 6
+            [x_primal, x_dual, Pp, Pm, Qp, Qm] = sbp.implementations.d1_staggered_6(m, L);
+          otherwise
+           error('Invalid operator order %d.',order);
+          end
+
+          obj.m = m;
+          obj.m_primal = m_primal;
+          obj.m_dual = m_dual;
+          obj.x_primal = x_l + x_primal';
+          obj.x_dual = x_l + x_dual';
+
+          D1_primal = Pp\Qp;
+          D1_dual = Pm\Qm;
+
+          obj.D1_primal = D1_primal;
+          obj.D1_dual = D1_dual;
+          obj.H_primal = Pp;
+          obj.H_dual = Pm; 
+
+          obj.e_primal_l = sparse(m_primal,1);
+          obj.e_primal_r = sparse(m_primal,1);
+          obj.e_primal_l(1) = 1;
+          obj.e_primal_r(m_primal) = 1;
+
+          obj.e_dual_l = sparse(m_dual,1);
+          obj.e_dual_r = sparse(m_dual,1);
+          obj.e_dual_l(1) = 1;
+          obj.e_dual_r(m_dual) = 1;
+
+          obj.H_primalI = inv(obj.H_primal);
+          obj.H_dualI = inv(obj.H_dual);
+
+          obj.borrowing = [];
+          obj.x = [];
+
+        end
+
+        function str = string(obj)
+            str = [class(obj) '_' num2str(obj.order)];
+        end
+    end
+end
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+sbp/D1StaggeredUpwind.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,95 @@
+classdef D1StaggeredUpwind < sbp.OpSet
+    % Compatible staggered and upwind operators by Ken Mattsson and Ossian O'reilly
+    properties
+        % x_primal: "primal" grid with m points. Equidistant. Called Plus grid in Ossian's paper.
+        % x_dual: "dual" grid with m+1 points. Called Minus grid in Ossian's paper.
+
+        % D1_primal takes FROM dual grid TO primal grid
+        % D1_dual takes FROM primal grid TO dual grid
+
+        D1_primal % SBP operator approximating first derivative
+        D1_dual % SBP operator approximating first derivative
+
+        Dplus_primal  % Upwind operator on primal grid 
+        Dminus_primal % Upwind operator on primal grid 
+        Dplus_dual % Upwind operator on dual grid 
+        Dminus_dual % Upwind operator on dual grid 
+
+        H_primal % Norm matrix
+        H_dual % Norm matrix
+        H_primalI % H^-1
+        H_dualI % H^-1
+        e_primal_l % Left boundary operator
+        e_dual_l % Left boundary operator
+        e_primal_r % Right boundary operator
+        e_dual_r % Right boundary operator
+        m % Number of grid points.
+        m_primal % Number of grid points.
+        m_dual % Number of grid points.
+        h % Step size
+        x_primal % grid
+        x_dual % grid
+        x
+        borrowing % Struct with borrowing limits for different norm matrices
+    end
+
+    methods
+        function obj = D1StaggeredUpwind(m,lim,order)
+
+          x_l = lim{1};
+          x_r = lim{2};
+          L = x_r-x_l;
+
+          m_primal = m;
+          m_dual = m+1;
+
+          switch order
+          case 2
+            [obj.x_primal, obj.x_dual, obj.H_primal, obj.H_dual,...
+            obj.H_primalI, obj.H_dualI,...
+            obj.D1_primal, obj.D1_dual, obj.Dplus_primal, obj.Dminus_primal,...
+            obj.Dplus_dual, obj.Dminus_dual] = sbp.implementations.d1_staggered_upwind_2(m, L);
+          case 4
+            [obj.x_primal, obj.x_dual, obj.H_primal, obj.H_dual,...
+            obj.H_primalI, obj.H_dualI,...
+            obj.D1_primal, obj.D1_dual, obj.Dplus_primal, obj.Dminus_primal,...
+            obj.Dplus_dual, obj.Dminus_dual] = sbp.implementations.d1_staggered_upwind_4(m, L);
+          case 6
+            [obj.x_primal, obj.x_dual, obj.H_primal, obj.H_dual,...
+            obj.H_primalI, obj.H_dualI,...
+            obj.D1_primal, obj.D1_dual, obj.Dplus_primal, obj.Dminus_primal,...
+            obj.Dplus_dual, obj.Dminus_dual] = sbp.implementations.d1_staggered_upwind_6(m, L);
+          case 8
+            [obj.x_primal, obj.x_dual, obj.H_primal, obj.H_dual,...
+            obj.H_primalI, obj.H_dualI,...
+            obj.D1_primal, obj.D1_dual, obj.Dplus_primal, obj.Dminus_primal,...
+            obj.Dplus_dual, obj.Dminus_dual] = sbp.implementations.d1_staggered_upwind_8(m, L);
+          otherwise
+           error('Invalid operator order %d.',order);
+          end
+
+          obj.m = m;
+          obj.m_primal = m_primal;
+          obj.m_dual = m_dual;
+          obj.h = L/(m-1);
+
+          obj.e_primal_l = sparse(m_primal,1);
+          obj.e_primal_r = sparse(m_primal,1);
+          obj.e_primal_l(1) = 1;
+          obj.e_primal_r(m_primal) = 1;
+
+          obj.e_dual_l = sparse(m_dual,1);
+          obj.e_dual_r = sparse(m_dual,1);
+          obj.e_dual_l(1) = 1;
+          obj.e_dual_r(m_dual) = 1;
+
+          obj.borrowing = [];
+          obj.x = [];
+
+        end
+
+        function str = string(obj)
+            str = [class(obj) '_' num2str(obj.order)];
+        end
+    end
+end
--- a/+scheme/Elastic2dVariable.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+scheme/Elastic2dVariable.m	Wed Nov 28 17:35:19 2018 -0800
@@ -30,17 +30,7 @@
         T_l, T_r
         tau_l, tau_r
 
-        H, Hi % Inner products
-
-        phi % Borrowing constant for (d1 - e^T*D1) from R
-        gamma % Borrowing constant for d1 from M
-        H11 % First element of H
-
-        % Borrowing from H, M, and R
-        thH
-        thM
-        thR
-
+        H, Hi, H_1D % Inner products
         e_l, e_r
         d1_l, d1_r % Normal derivatives at the boundary
         E % E{i}^T picks out component i
@@ -50,22 +40,38 @@
         % Kroneckered norms and coefficients
         RHOi_kron
         Hi_kron
+
+        % Borrowing constants of the form gamma*h, where gamma is a dimensionless constant.
+        theta_R % Borrowing (d1- D1)^2 from R
+        theta_H % First entry in norm matrix
+        theta_M % Borrowing d1^2 from M.
+
+        % Structures used for adjoint optimization
+        B
     end
 
     methods
 
-        function obj = Elastic2dVariable(g ,order, lambda_fun, mu_fun, rho_fun, opSet)
+        % The coefficients can either be function handles or grid functions
+        function obj = Elastic2dVariable(g ,order, lambda, mu, rho, opSet)
             default_arg('opSet',{@sbp.D2Variable, @sbp.D2Variable});
-            default_arg('lambda_fun', @(x,y) 0*x+1);
-            default_arg('mu_fun', @(x,y) 0*x+1);
-            default_arg('rho_fun', @(x,y) 0*x+1);
+            default_arg('lambda', @(x,y) 0*x+1);
+            default_arg('mu', @(x,y) 0*x+1);
+            default_arg('rho', @(x,y) 0*x+1);
             dim = 2;
 
             assert(isa(g, 'grid.Cartesian'))
 
-            lambda = grid.evalOn(g, lambda_fun);
-            mu = grid.evalOn(g, mu_fun);
-            rho = grid.evalOn(g, rho_fun);
+            if isa(lambda, 'function_handle')
+                lambda = grid.evalOn(g, lambda);
+            end
+            if isa(mu, 'function_handle')
+                mu = grid.evalOn(g, mu);
+            end
+            if isa(rho, 'function_handle')
+                rho = grid.evalOn(g, rho);
+            end
+
             m = g.size();
             m_tot = g.N();
 
@@ -87,15 +93,9 @@
 
             % Borrowing constants
             for i = 1:dim
-                beta = ops{i}.borrowing.R.delta_D;
-                obj.H11{i} = ops{i}.borrowing.H11;
-                obj.phi{i} = beta/obj.H11{i};
-                obj.gamma{i} = ops{i}.borrowing.M.d1;
-
-                % Better names
-                obj.thR{i} = ops{i}.borrowing.R.delta_D;
-                obj.thM{i} = ops{i}.borrowing.M.d1;
-                obj.thH{i} = ops{i}.borrowing.H11;
+                obj.theta_R{i} = h(i)*ops{i}.borrowing.R.delta_D;
+                obj.theta_H{i} = h(i)*ops{i}.borrowing.H11;
+                obj.theta_M{i} = h(i)*ops{i}.borrowing.M.d1;
             end
 
             I = cell(dim,1);
@@ -183,6 +183,7 @@
             obj.H_boundary = cell(dim,1);
             obj.H_boundary{1} = H{2};
             obj.H_boundary{2} = H{1};
+            obj.H_1D = {H{1}, H{2}};
 
             % E{i}^T picks out component i.
             E = cell(dim,1);
@@ -213,7 +214,7 @@
                 end
             end
             obj.D = D;
-            %=========================================%
+            %=========================================%'
 
             % Numerical traction operators for BC.
             % Because d1 =/= e0^T*D1, the numerical tractions are different
@@ -275,6 +276,17 @@
             obj.grid = g;
             obj.dim = dim;
 
+            % Used for adjoint optimization
+            obj.B = cell(1,dim);
+            for i = 1:dim
+                obj.B{i} = zeros(m(i),m(i),m(i));
+                for k = 1:m(i)
+                    c = sparse(m(i),1);
+                    c(k) = 1;
+                    [~, obj.B{i}(:,:,k)] = ops{i}.D2(c);
+                end
+            end
+
         end
 
 
@@ -316,14 +328,13 @@
             % Dirichlet boundary condition
             case {'D','d','dirichlet','Dirichlet'}
 
-                phi = obj.phi{j};
-                h = obj.h(j);
-                h11 = obj.H11{j}*h;
-                gamma = obj.gamma{j};
+                theta_R = obj.theta_R{j};
+                theta_H = obj.theta_H{j};
+                theta_M = obj.theta_M{j};
 
-                a_lambda = dim/h11 + 1/(h11*phi);
-                a_mu_i = 2/(gamma*h);
-                a_mu_ij = 2/h11 + 1/(h11*phi);
+                a_lambda = dim/theta_H + 1/theta_R;
+                a_mu_i = 2/theta_M;
+                a_mu_ij = 2/theta_H + 1/theta_R;
 
                 d = @kroneckerDelta;  % Kronecker delta
                 db = @(i,j) 1-d(i,j); % Logical not of Kronecker delta
@@ -387,27 +398,27 @@
             %-------------------------
 
             % Borrowing constants
-            h_u = obj.h(j);
-            thR_u = obj.thR{j}*h_u;
-            thM_u = obj.thM{j}*h_u;
-            thH_u = obj.thH{j}*h_u;
+            theta_R_u = obj.theta_R{j};
+            theta_H_u = obj.theta_H{j};
+            theta_M_u = obj.theta_M{j};
+
+            theta_R_v = neighbour_scheme.theta_R{j_v};
+            theta_H_v = neighbour_scheme.theta_H{j_v};
+            theta_M_v = neighbour_scheme.theta_M{j_v};
 
-            h_v = neighbour_scheme.h(j_v);
-            thR_v = neighbour_scheme.thR{j_v}*h_v;
-            thH_v = neighbour_scheme.thH{j_v}*h_v;
-            thM_v = neighbour_scheme.thM{j_v}*h_v;
+            function [alpha_ii, alpha_ij] = computeAlpha(th_R, th_H, th_M, lambda, mu)
+                alpha_ii = dim*lambda/(4*th_H) + lambda/(4*th_R) + mu/(2*th_M);
+                alpha_ij = mu/(2*th_H) + mu/(4*th_R);
+            end
 
-            % alpha = penalty strength for normal component, beta for tangential
-            alpha_u = dim*lambda_u/(4*thH_u) + lambda_u/(4*thR_u) + mu_u/(2*thM_u);
-            alpha_v = dim*lambda_v/(4*thH_v) + lambda_v/(4*thR_v) + mu_v/(2*thM_v);
-            beta_u = mu_u/(2*thH_u) + mu_u/(4*thR_u);
-            beta_v = mu_v/(2*thH_v) + mu_v/(4*thR_v);
-            alpha = alpha_u + alpha_v;
-            beta = beta_u + beta_v;
+            [alpha_ii_u, alpha_ij_u] = computeAlpha(theta_R_u, theta_H_u, theta_M_u, lambda_u, mu_u);
+            [alpha_ii_v, alpha_ij_v] = computeAlpha(theta_R_v, theta_H_v, theta_M_v, lambda_v, mu_v);
+            sigma_ii = tuning*(alpha_ii_u + alpha_ii_v);
+            sigma_ij = tuning*(alpha_ij_u + alpha_ij_v);
 
             d = @kroneckerDelta;  % Kronecker delta
             db = @(i,j) 1-d(i,j); % Logical not of Kronecker delta
-            strength = @(i,j) tuning*(d(i,j)*alpha + db(i,j)*beta);
+            sigma = @(i,j) tuning*(d(i,j)*sigma_ii + db(i,j)*sigma_ij);
 
             % Preallocate
             closure = sparse(dim*m_tot_u, dim*m_tot_u);
@@ -415,8 +426,8 @@
 
             % Loop over components that penalties end up on
             for i = 1:dim
-                closure = closure - E{i}*RHOi*Hi*e*strength(i,j)*H_gamma*e'*E{i}';
-                penalty = penalty + E{i}*RHOi*Hi*e*strength(i,j)*H_gamma*e_v'*E_v{i}';
+                closure = closure - E{i}*RHOi*Hi*e*sigma(i,j)*H_gamma*e'*E{i}';
+                penalty = penalty + E{i}*RHOi*Hi*e*sigma(i,j)*H_gamma*e_v'*E_v{i}';
 
                 closure = closure - 1/2*E{i}*RHOi*Hi*e*H_gamma*e'*tau{i};
                 penalty = penalty - 1/2*E{i}*RHOi*Hi*e*H_gamma*e_v'*tau_v{i};
@@ -498,6 +509,28 @@
                             case {'e', 'E', 'east', 'East','n', 'N', 'north', 'North'}
                                 varargout{i} = obj.tau_r{j};
                         end
+                    case 'alpha'
+                        % alpha = alpha(i,j) is the penalty strength for displacement BC.
+                        tuning = 1.2;
+                        LAMBDA = obj.LAMBDA;
+                        MU = obj.MU;
+
+                        phi = obj.phi{j};
+                        h = obj.h(j);
+                        h11 = obj.H11{j}*h;
+                        gamma = obj.gamma{j};
+                        dim = obj.dim;
+
+                        a_lambda = dim/h11 + 1/(h11*phi);
+                        a_mu_i = 2/(gamma*h);
+                        a_mu_ij = 2/h11 + 1/(h11*phi);
+
+                        d = @kroneckerDelta;  % Kronecker delta
+                        db = @(i,j) 1-d(i,j); % Logical not of Kronecker delta
+                        alpha = @(i,k) d(i,k)*tuning*( d(i,j)* a_lambda*LAMBDA ...
+                                                     + d(i,j)* a_mu_i*MU ...
+                                                     + db(i,j)*a_mu_ij*MU );
+                        varargout{i} = alpha;
                     otherwise
                         error(['No such operator: operator = ' op{i}]);
                 end
--- a/+scheme/LaplaceCurvilinear.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+scheme/LaplaceCurvilinear.m	Wed Nov 28 17:35:19 2018 -0800
@@ -38,22 +38,29 @@
         du_n, dv_n
         gamm_u, gamm_v
         lambda
+
+        interpolation_type
     end
 
     methods
         % Implements  a*div(b*grad(u)) as a SBP scheme
         % TODO: Implement proper H, it should be the real physical quadrature, the logic quadrature may be but in a separate variable (H_logic?)
 
-        function obj = LaplaceCurvilinear(g ,order, a, b, opSet)
+        function obj = LaplaceCurvilinear(g ,order, a, b, opSet, interpolation_type)
             default_arg('opSet',@sbp.D2Variable);
             default_arg('a', 1);
             default_arg('b', 1);
+            default_arg('interpolation_type','AWW');
 
             if b ~=1
                 error('Not implemented yet')
             end
 
-            assert(isa(g, 'grid.Curvilinear'))
+            % assert(isa(g, 'grid.Curvilinear'))
+            if isa(a, 'function_handle')
+                a = grid.evalOn(g, a);
+                a = spdiag(a);
+            end
 
             m = g.size();
             m_u = m(1);
@@ -209,6 +216,7 @@
             obj.h = [h_u h_v];
             obj.order = order;
             obj.grid = g;
+            obj.interpolation_type = interpolation_type;
 
             obj.a = a;
             obj.b = b;
@@ -269,13 +277,70 @@
         end
 
         function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+
+            [e_u, d_u, gamm_u, H_b_u, I_u] = obj.get_boundary_ops(boundary);
+            [e_v, d_v, gamm_v, H_b_v, I_v] = neighbour_scheme.get_boundary_ops(neighbour_boundary);
+            Hi = obj.Hi;
+            a = obj.a;
+
+            m_u = length(H_b_u);
+            m_v = length(H_b_v);
+
+            grid_ratio = m_u/m_v;
+             if grid_ratio ~= 1
+
+                [ms, index] = sort([m_u, m_v]);
+                orders = [obj.order, neighbour_scheme.order];
+                orders = orders(index);
+
+                switch obj.interpolation_type
+                case 'MC'
+                    interpOpSet = sbp.InterpMC(ms(1),ms(2),orders(1),orders(2));
+                    if grid_ratio < 1
+                        I_v2u_good = interpOpSet.IF2C;
+                        I_v2u_bad = interpOpSet.IF2C;
+                        I_u2v_good = interpOpSet.IC2F;
+                        I_u2v_bad = interpOpSet.IC2F;
+                    elseif grid_ratio > 1
+                        I_v2u_good = interpOpSet.IC2F;
+                        I_v2u_bad = interpOpSet.IC2F;
+                        I_u2v_good = interpOpSet.IF2C;
+                        I_u2v_bad = interpOpSet.IF2C;
+                    end
+                case 'AWW'
+                    %String 'C2F' indicates that ICF2 is more accurate.
+                    interpOpSetF2C = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'F2C');
+                    interpOpSetC2F = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'C2F'); 
+                    if grid_ratio < 1 
+                        % Local is coarser than neighbour
+                        I_v2u_good = interpOpSetF2C.IF2C;
+                        I_v2u_bad = interpOpSetC2F.IF2C;
+                        I_u2v_good = interpOpSetC2F.IC2F;
+                        I_u2v_bad = interpOpSetF2C.IC2F;
+                    elseif grid_ratio > 1
+                        % Local is finer than neighbour 
+                        I_v2u_good = interpOpSetC2F.IC2F;
+                        I_v2u_bad = interpOpSetF2C.IC2F;
+                        I_u2v_good = interpOpSetF2C.IF2C;
+                        I_u2v_bad = interpOpSetC2F.IF2C;
+                    end
+                otherwise
+                    error(['Interpolation type ' obj.interpolation_type ...
+                         ' is not available.' ]);
+                end
+
+             else 
+                % No interpolation required
+                I_v2u_good = speye(m_u,m_u);
+                I_v2u_bad = speye(m_u,m_u);
+                I_u2v_good = speye(m_u,m_u);
+                I_u2v_bad = speye(m_u,m_u);
+            end
+
             % u denotes the solution in the own domain
             % v denotes the solution in the neighbour domain
             tuning = 1.2;
             % tuning = 20.2;
-            [e_u, d_u, gamm_u, H_b_u, I_u] = obj.get_boundary_ops(boundary);
-            [e_v, d_v, gamm_v, H_b_v, I_v] = neighbour_scheme.get_boundary_ops(neighbour_boundary);
-
             u = obj;
             v = neighbour_scheme;
 
@@ -284,18 +349,24 @@
             b1_v = gamm_v*v.lambda(I_v)./v.a11(I_v).^2;
             b2_v = gamm_v*v.lambda(I_v)./v.a22(I_v).^2;
 
-            tau1 = -1./(4*b1_u) -1./(4*b1_v) -1./(4*b2_u) -1./(4*b2_v);
-            tau1 = tuning * spdiag(tau1);
-            tau2 = 1/2;
+            tau_u = -1./(4*b1_u) -1./(4*b2_u);
+            tau_v = -1./(4*b1_v) -1./(4*b2_v);
+
+            tau_u = tuning * spdiag(tau_u);
+            tau_v = tuning * spdiag(tau_v);
+            beta_u = tau_v;
 
-            sig1 = -1/2;
-            sig2 = 0;
+            closure = a*Hi*e_u*tau_u*H_b_u*e_u' + ...
+                      a*Hi*e_u*H_b_u*I_v2u_bad*beta_u*I_u2v_good*e_u' + ...
+                      a*1/2*Hi*d_u*H_b_u*e_u' + ...
+                      -a*1/2*Hi*e_u*H_b_u*d_u';
 
-            tau = (e_u*tau1 + tau2*d_u)*H_b_u;
-            sig = (sig1*e_u + sig2*d_u)*H_b_u;
+            penalty = -a*Hi*e_u*tau_u*H_b_u*I_v2u_good*e_v' + ...
+                      -a*Hi*e_u*H_b_u*I_v2u_bad*beta_u*e_v' + ...
+                      -a*1/2*Hi*d_u*H_b_u*I_v2u_good*e_v' + ...
+                      -a*1/2*Hi*e_u*H_b_u*I_v2u_bad*d_v';
+            
 
-            closure = obj.a*obj.Hi*( tau*e_u' + sig*d_u');
-            penalty = obj.a*obj.Hi*(-tau*e_v' + sig*d_v');
         end
 
         % Ruturns the boundary ops and sign for the boundary specified by the string boundary.
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+scheme/Schrodinger2d.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,374 @@
+classdef Schrodinger2d < scheme.Scheme
+
+% Discretizes the Laplacian with constant coefficent,
+% in the Schrödinger equation way (i.e., the discretization matrix is not necessarily 
+% definite)
+% u_t = a*i*Laplace u 
+% opSet should be cell array of opSets, one per dimension. This
+% is useful if we have periodic BC in one direction.
+
+    properties
+        m % Number of points in each direction, possibly a vector
+        h % Grid spacing
+
+        grid
+        dim
+
+        order % Order of accuracy for the approximation
+
+        % Diagonal matrix for variable coefficients
+        a % Constant coefficient
+
+        D % Total operator
+        D1 % First derivatives
+
+        % Second derivatives
+        D2
+
+        H, Hi % Inner products
+        e_l, e_r
+        d1_l, d1_r % Normal derivatives at the boundary
+        e_w, e_e, e_s, e_n
+        d_w, d_e, d_s, d_n
+        
+        H_boundary % Boundary inner products
+
+        interpolation_type % MC or AWW
+
+    end
+
+    methods
+
+        function obj = Schrodinger2d(g ,order, a, opSet, interpolation_type)
+            default_arg('interpolation_type','AWW');
+            default_arg('opSet',{@sbp.D2Variable, @sbp.D2Variable});
+            default_arg('a',1);
+            dim = 2;
+
+            assert(isa(g, 'grid.Cartesian'))
+            if isa(a, 'function_handle')
+                a = grid.evalOn(g, a);
+                a = spdiag(a);
+            end
+
+            m = g.size();
+            m_tot = g.N();
+
+            h = g.scaling();
+            xlim = {g.x{1}(1), g.x{1}(end)};
+            ylim = {g.x{2}(1), g.x{2}(end)};
+            lim = {xlim, ylim};
+
+            % 1D operators
+            ops = cell(dim,1);
+            for i = 1:dim
+                ops{i} = opSet{i}(m(i), lim{i}, order);
+            end
+
+            I = cell(dim,1);
+            D1 = cell(dim,1);
+            D2 = cell(dim,1);
+            H = cell(dim,1);
+            Hi = cell(dim,1);
+            e_l = cell(dim,1);
+            e_r = cell(dim,1);
+            d1_l = cell(dim,1);
+            d1_r = cell(dim,1);
+
+            for i = 1:dim
+                I{i} = speye(m(i));
+                D1{i} = ops{i}.D1;
+                D2{i} = ops{i}.D2;
+                H{i} =  ops{i}.H;
+                Hi{i} = ops{i}.HI;
+                e_l{i} = ops{i}.e_l;
+                e_r{i} = ops{i}.e_r;
+                d1_l{i} = ops{i}.d1_l;
+                d1_r{i} = ops{i}.d1_r;
+            end
+
+            % Constant coeff D2
+            for i = 1:dim
+                D2{i} = D2{i}(ones(m(i),1));
+            end
+
+            %====== Assemble full operators ========
+            obj.D1 = cell(dim,1);
+            obj.D2 = cell(dim,1);
+            obj.e_l = cell(dim,1);
+            obj.e_r = cell(dim,1);
+            obj.d1_l = cell(dim,1);
+            obj.d1_r = cell(dim,1);
+
+            % D1
+            obj.D1{1} = kron(D1{1},I{2});
+            obj.D1{2} = kron(I{1},D1{2});
+
+            % Boundary operators
+            obj.e_l{1} = kron(e_l{1},I{2});
+            obj.e_l{2} = kron(I{1},e_l{2});
+            obj.e_r{1} = kron(e_r{1},I{2});
+            obj.e_r{2} = kron(I{1},e_r{2});
+
+            obj.d1_l{1} = kron(d1_l{1},I{2});
+            obj.d1_l{2} = kron(I{1},d1_l{2});
+            obj.d1_r{1} = kron(d1_r{1},I{2});
+            obj.d1_r{2} = kron(I{1},d1_r{2});
+
+            % D2
+            obj.D2{1} = kron(D2{1},I{2});
+            obj.D2{2} = kron(I{1},D2{2});
+
+            % Quadratures
+            obj.H = kron(H{1},H{2});
+            obj.Hi = inv(obj.H);
+            obj.H_boundary = cell(dim,1);
+            obj.H_boundary{1} = H{2};
+            obj.H_boundary{2} = H{1};
+
+            % Differentiation matrix D (without SAT)
+            D2 = obj.D2;
+            D = sparse(m_tot,m_tot);
+            for j = 1:dim
+                D = D + a*1i*D2{j};
+            end
+            obj.D = D;
+            %=========================================%
+
+            % Misc.
+            obj.m = m;
+            obj.h = h;
+            obj.order = order;
+            obj.grid = g;
+            obj.dim = dim;
+            obj.a = a;
+            obj.e_w = obj.e_l{1};
+            obj.e_e = obj.e_r{1};
+            obj.e_s = obj.e_l{2};
+            obj.e_n = obj.e_r{2};
+            obj.d_w = obj.d1_l{1};
+            obj.d_e = obj.d1_r{1};
+            obj.d_s = obj.d1_l{2};
+            obj.d_n = obj.d1_r{2};
+            obj.interpolation_type = interpolation_type;
+
+        end
+
+
+        % Closure functions return the operators applied to the own domain to close the boundary
+        % Penalty functions return the operators to force the solution. In the case of an interface it returns the operator applied to the other doamin.
+        %       boundary            is a string specifying the boundary e.g. 'l','r' or 'e','w','n','s'.
+        %       type                is a string specifying the type of boundary condition.
+        %       data                is a function returning the data that should be applied at the boundary.
+        %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
+        %       neighbour_boundary  is a string specifying which boundary to interface to.
+        function [closure, penalty] = boundary_condition(obj, boundary, type, parameter)
+            default_arg('type','Neumann');
+            default_arg('parameter', []);
+
+            % j is the coordinate direction of the boundary
+            % nj: outward unit normal component. 
+            % nj = -1 for west, south, bottom boundaries
+            % nj = 1  for east, north, top boundaries
+            [j, nj] = obj.get_boundary_number(boundary);
+            switch nj
+            case 1
+                e = obj.e_r;
+                d = obj.d1_r;
+            case -1
+                e = obj.e_l;
+                d = obj.d1_l;
+            end
+
+            Hi = obj.Hi;
+            H_gamma = obj.H_boundary{j};
+            a = e{j}'*obj.a*e{j};
+
+            switch type
+
+            % Dirichlet boundary condition
+            case {'D','d','dirichlet','Dirichlet'}
+                    closure =  nj*Hi*d{j}*a*1i*H_gamma*(e{j}' ); 
+                    penalty = -nj*Hi*d{j}*a*1i*H_gamma;
+
+            % Free boundary condition
+            case {'N','n','neumann','Neumann'}
+                    closure = -nj*Hi*e{j}*a*1i*H_gamma*(d{j}' ); 
+                    penalty =  nj*Hi*e{j}*a*1i*H_gamma; 
+
+            % Unknown boundary condition
+            otherwise
+                error('No such boundary condition: type = %s',type);
+            end
+        end
+
+        function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+            % u denotes the solution in the own domain
+            % v denotes the solution in the neighbour domain
+            % Get neighbour boundary operator
+
+            [coord_nei, n_nei] = get_boundary_number(obj, neighbour_boundary);
+            [coord, n] = get_boundary_number(obj, boundary);
+            switch n_nei
+            case 1
+                % North or east boundary
+                e_neighbour = neighbour_scheme.e_r;
+                d_neighbour = neighbour_scheme.d1_r;
+            case -1
+                % South or west boundary
+                e_neighbour = neighbour_scheme.e_l;
+                d_neighbour = neighbour_scheme.d1_l;
+            end
+
+            e_neighbour = e_neighbour{coord_nei};
+            d_neighbour = d_neighbour{coord_nei};
+            H_gamma = obj.H_boundary{coord};
+            Hi = obj.Hi;
+            a = obj.a;
+
+            switch coord_nei
+            case 1
+                m_neighbour = neighbour_scheme.m(2);
+            case 2
+                m_neighbour = neighbour_scheme.m(1);
+            end
+
+            switch coord
+            case 1
+                m = obj.m(2);
+            case 2
+                m = obj.m(1);
+            end
+
+           switch n
+            case 1
+                % North or east boundary
+                e = obj.e_r;
+                d = obj.d1_r;
+            case -1
+                % South or west boundary
+                e = obj.e_l;
+                d = obj.d1_l;
+            end
+            e = e{coord};
+            d = d{coord}; 
+
+            Hi = obj.Hi;
+            sigma = -n*1i*a/2;
+            tau = -n*(1i*a)'/2;
+
+            grid_ratio = m/m_neighbour;
+             if grid_ratio ~= 1
+
+                [ms, index] = sort([m, m_neighbour]);
+                orders = [obj.order, neighbour_scheme.order];
+                orders = orders(index);
+
+                switch obj.interpolation_type
+                case 'MC'
+                    interpOpSet = sbp.InterpMC(ms(1),ms(2),orders(1),orders(2));
+                    if grid_ratio < 1
+                        I_neighbour2local_e = interpOpSet.IF2C;
+                        I_neighbour2local_d = interpOpSet.IF2C;
+                        I_local2neighbour_e = interpOpSet.IC2F;
+                        I_local2neighbour_d = interpOpSet.IC2F;
+                    elseif grid_ratio > 1
+                        I_neighbour2local_e = interpOpSet.IC2F;
+                        I_neighbour2local_d = interpOpSet.IC2F;
+                        I_local2neighbour_e = interpOpSet.IF2C;
+                        I_local2neighbour_d = interpOpSet.IF2C;
+                    end
+                case 'AWW'
+                    %String 'C2F' indicates that ICF2 is more accurate.
+                    interpOpSetF2C = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'F2C');
+                    interpOpSetC2F = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'C2F'); 
+                    if grid_ratio < 1 
+                        % Local is coarser than neighbour
+                        I_neighbour2local_e = interpOpSetF2C.IF2C;
+                        I_neighbour2local_d = interpOpSetC2F.IF2C;
+                        I_local2neighbour_e = interpOpSetC2F.IC2F;
+                        I_local2neighbour_d = interpOpSetF2C.IC2F;
+                    elseif grid_ratio > 1
+                        % Local is finer than neighbour 
+                        I_neighbour2local_e = interpOpSetC2F.IC2F;
+                        I_neighbour2local_d = interpOpSetF2C.IC2F;
+                        I_local2neighbour_e = interpOpSetF2C.IF2C;
+                        I_local2neighbour_d = interpOpSetC2F.IF2C;
+                    end
+                otherwise
+                    error(['Interpolation type ' obj.interpolation_type ...
+                         ' is not available.' ]);
+                end
+
+             else 
+                % No interpolation required
+                I_neighbour2local_e = speye(m,m);
+                I_neighbour2local_d = speye(m,m);
+                I_local2neighbour_e = speye(m,m);
+                I_local2neighbour_d = speye(m,m);
+            end
+
+            closure = tau*Hi*d*H_gamma*e' + sigma*Hi*e*H_gamma*d';
+            penalty = -tau*Hi*d*H_gamma*I_neighbour2local_e*e_neighbour' ...
+                      -sigma*Hi*e*H_gamma*I_neighbour2local_d*d_neighbour'; 
+             
+        end
+
+        % Returns the coordinate number and outward normal component for the boundary specified by the string boundary.
+        function [j, nj] = get_boundary_number(obj, boundary)
+
+            switch boundary
+                case {'w','W','west','West', 'e', 'E', 'east', 'East'}
+                    j = 1;
+                case {'s','S','south','South', 'n', 'N', 'north', 'North'}
+                    j = 2;
+                otherwise
+                    error('No such boundary: boundary = %s',boundary);
+            end
+
+            switch boundary
+                case {'w','W','west','West','s','S','south','South'}
+                    nj = -1;
+                case {'e', 'E', 'east', 'East','n', 'N', 'north', 'North'}
+                    nj = 1;
+            end
+        end
+
+        % Returns the coordinate number and outward normal component for the boundary specified by the string boundary.
+        function [return_op] = get_boundary_operator(obj, op, boundary)
+
+            switch boundary
+                case {'w','W','west','West', 'e', 'E', 'east', 'East'}
+                    j = 1;
+                case {'s','S','south','South', 'n', 'N', 'north', 'North'}
+                    j = 2;
+                otherwise
+                    error('No such boundary: boundary = %s',boundary);
+            end
+
+            switch op
+                case 'e'
+                    switch boundary
+                        case {'w','W','west','West','s','S','south','South'}
+                            return_op = obj.e_l{j};
+                        case {'e', 'E', 'east', 'East','n', 'N', 'north', 'North'}
+                            return_op = obj.e_r{j};
+                    end
+                case 'd'
+                    switch boundary
+                        case {'w','W','west','West','s','S','south','South'}
+                            return_op = obj.d1_l{j};
+                        case {'e', 'E', 'east', 'East','n', 'N', 'north', 'North'}
+                            return_op = obj.d1_r{j};
+                    end
+                otherwise
+                    error(['No such operator: operator = ' op]);
+            end
+
+        end
+
+        function N = size(obj)
+            N = prod(obj.m);
+        end
+    end
+end
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+scheme/Staggered1DAcoustics.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,231 @@
+classdef Staggered1DAcoustics < scheme.Scheme
+   properties
+        m % Number of points of primal grid in each direction, possibly a vector
+        h % Grid spacing
+        
+        % Grids
+        grid % Total grid object
+        grid_primal 
+        grid_dual
+
+        order % Order accuracy for the approximation
+
+        H  % Combined norm
+        Hi % Inverse
+        D % Semi-discrete approximation matrix
+
+        D1_primal
+        D1_dual
+
+        % Pick out left or right boundary
+        e_l
+        e_r
+
+        % Initial data
+        v0
+
+        % Pick out primal or dual component
+        e_primal
+        e_dual
+
+        % System matrices
+        A
+        B
+    end
+
+
+    methods
+         % Scheme for A*u_t + B u_x = 0, 
+         % u = [p, v];
+         % A: Diagonal and A > 0,
+         % A = [a1, 0;
+         %      0,  a2]
+         % 
+         % B = B^T and with diagonal entries = 0.
+         % B = [0 b 
+         %     b 0] 
+         % Here we store p on the primal grid and v on the dual
+         function obj = Staggered1DAcoustics(g, order, A, B)
+            default_arg('A',[1, 0; 0, 1]);
+            default_arg('B',[0, 1; 1, 0]);
+
+            obj.order = order;
+            obj.A = A;
+            obj.B = B;
+
+            % Grids
+            obj.m = g.size();
+            xl = g.getBoundary('l');
+            xr = g.getBoundary('r');
+            xlim = {xl, xr};
+                
+            obj.grid = g;
+            obj.grid_primal = g.grids{1};
+            obj.grid_dual = g.grids{2};
+            
+            % Get operators
+            ops = sbp.D1StaggeredUpwind(obj.m, xlim, order);
+            obj.h = ops.h;
+
+            % Build combined operators
+            H_primal = ops.H_primal;
+            H_dual = ops.H_dual;
+            obj.H = blockmatrix.toMatrix( {H_primal, []; [], H_dual } );
+            obj.Hi = inv(obj.H);
+        
+            D1_primal = ops.D1_primal;
+            D1_dual = ops.D1_dual;
+            D = {[],                -1/A(1,1)*B(1,2)*D1_primal;...
+                 -1/A(2,2)*B(2,1)*D1_dual,     []};
+            obj.D = blockmatrix.toMatrix(D); 
+            obj.D1_primal = D1_primal;
+            obj.D1_dual = D1_dual;
+
+            % Combined boundary operators
+            e_primal_l = ops.e_primal_l;
+            e_primal_r = ops.e_primal_r;
+            e_dual_l = ops.e_dual_l;
+            e_dual_r = ops.e_dual_r;
+            e_l = {e_primal_l, [];...  
+                   []       ,  e_dual_l};
+            e_r = {e_primal_r, [];...  
+                   []       ,  e_dual_r};
+            obj.e_l = blockmatrix.toMatrix(e_l);
+            obj.e_r = blockmatrix.toMatrix(e_r);
+
+            % Pick out first or second component of solution
+            N_primal = obj.grid_primal.N();
+            N_dual = obj.grid_dual.N();
+            obj.e_primal = [speye(N_primal, N_primal); sparse(N_dual, N_primal)];
+            obj.e_dual = [sparse(N_primal, N_dual); speye(N_dual, N_dual)];
+
+
+        end
+        % Closure functions return the operators applied to the own domain to close the boundary
+        % Penalty functions return the operators to force the solution. In the case of an interface it returns the operator applied to the other domain.
+        %       boundary            is a string specifying the boundary e.g. 'l','r' or 'e','w','n','s'.
+        %       type                is a string specifying the type of boundary condition if there are several.
+        %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
+        %       neighbour_boundary  is a string specifying which boundary to interface to.
+        function [closure, penalty] = boundary_condition(obj, boundary, type)
+            
+            default_arg('type','p');
+
+            % type = 'p' => boundary condition for p
+            % type = 'v' => boundary condition for v
+            % type = 'characteristic' => incoming characteristc = data
+            % No other types implemented yet
+
+            % BC on the form Lu - g = 0;
+
+            % Need a transformation T such that w = T^{−1}*u is a
+            % meaningful change of variables and T^T*B*T is block-diagonal,
+            % For linear acoustics, T = T_C meets these criteria.
+
+            A = obj.A;
+            B = obj.B;
+            C = inv(A)*B;
+
+            % Diagonalize C and use T_C to diagonalize B
+            [T, ~] = eig(C);
+            Lambda = T'*B*T;
+            lambda = diag(Lambda);
+
+
+            % Identify in- and outgoing variables
+            Iplus = lambda > 0;
+            Iminus = lambda < 0;
+
+            switch boundary
+            case 'l'
+                Iin = Iplus;
+            case 'r'
+                Iin = Iminus;
+            end
+            Tin = T(:,Iin);
+
+            switch type
+            case 'p'
+                L = [1, 0];
+            case 'v'
+                L = [0, 1];
+            case 'characteristic'
+                % Diagonalize C
+                [T_C, Lambda_C] = eig(C);
+                lambda_C = diag(Lambda_C);
+                % Identify in- and outgoing characteristic variables
+                Iplus = lambda_C > 0;
+                Iminus = lambda_C < 0;
+
+                switch boundary
+                case 'l'
+                    Iin_C = Iplus;
+                case 'r'
+                    Iin_C = Iminus;
+                end
+                T_C_inv = inv(T_C);
+                L = T_C_inv(Iin_C,:);
+            otherwise
+                error('Boundary condition not implemented.');
+            end
+
+            % Penalty parameters
+            sigma = [0; 0];
+            sigma(Iin) = lambda(Iin);
+
+            % Sparsify
+            A = sparse(A);
+            T = sparse(T);
+            sigma = sparse(sigma);
+            L = sparse(L);
+            Tin = sparse(Tin);
+
+            switch boundary
+            case 'l'
+                tau = -1*obj.e_l * inv(A) * inv(T)' * sigma * inv(L*Tin);  
+                closure = obj.Hi*tau*L*obj.e_l';
+
+            case 'r'
+                tau = 1*obj.e_r * inv(A) * inv(T)' * sigma * inv(L*Tin);  
+                closure = obj.Hi*tau*L*obj.e_r';
+
+            end
+      
+            penalty = -obj.Hi*tau;
+                
+         end
+          
+         function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+
+            error('Staggered1DAcoustics, interface not implemented');
+
+             switch boundary
+                 % Upwind coupling
+                 case {'l','left'}
+                     tau = -1*obj.e_l;
+                     closure = obj.Hi*tau*obj.e_l';       
+                     penalty = -obj.Hi*tau*neighbour_scheme.e_r';
+                 case {'r','right'}
+                     tau = 0*obj.e_r;
+                     closure = obj.Hi*tau*obj.e_r';       
+                     penalty = -obj.Hi*tau*neighbour_scheme.e_l';
+             end
+                 
+         end
+      
+        function N = size(obj)
+            N = obj.m;
+        end
+
+    end
+
+    methods(Static)
+        % Calculates the matrices needed for the inteface coupling between boundary bound_u of scheme schm_u
+        % and bound_v of scheme schm_v.
+        %   [uu, uv, vv, vu] = inteface_coupling(A,'r',B,'l')
+        function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
+            [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
+            [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
+        end
+    end
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+scheme/Staggered1DAcousticsVariable.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,366 @@
+classdef Staggered1DAcousticsVariable < scheme.Scheme
+   properties
+        m % Number of points of primal grid in each direction, possibly a vector
+        h % Grid spacing
+
+        % Grids
+        grid % Total grid object
+        grid_primal
+        grid_dual
+
+        order % Order accuracy for the approximation
+
+        H  % Combined norm
+        Hi % Inverse
+        D % Semi-discrete approximation matrix
+
+        D1_primal
+        D1_dual
+
+        % Pick out left or right boundary
+        e_l
+        e_r
+
+        % Initial data
+        v0
+
+        % Pick out primal or dual component
+        e_primal
+        e_dual
+
+        % System matrices, cell matrices of function handles
+        A
+        B
+
+        % Variable coefficient matrices evaluated at boundaries.
+        A_l, A_r
+        B_l, B_r
+    end
+
+
+    methods
+         % Scheme for A*u_t + B u_x = 0,
+         % u = [p, v];
+         % A: Diagonal and A > 0,
+         % A = [a1, 0;
+         %      0,  a2]
+         %
+         % B = B^T and with diagonal entries = 0.
+         % B = [0 b
+         %     b 0]
+         % Here we store p on the primal grid and v on the dual
+         % A and B are cell matrices of function handles
+         function obj = Staggered1DAcousticsVariable(g, order, A, B)
+            default_arg('B',{@(x)0*x, @(x)0*x+1; @(x)0*x+1, @(x)0*x});
+            default_arg('A',{@(x)0*x+1, @(x)0*x; @(x)0*x, @(x)0*x+1});
+
+            obj.order = order;
+            obj.A = A;
+            obj.B = B;
+
+            % Grids
+            obj.m = g.size();
+            xl = g.getBoundary('l');
+            xr = g.getBoundary('r');
+            xlim = {xl, xr};
+            obj.grid = g;
+            obj.grid_primal = g.grids{1};
+            obj.grid_dual = g.grids{2};
+            x_primal = obj.grid_primal.points();
+            x_dual = obj.grid_dual.points();
+
+            % If coefficients are function handles, evaluate them
+            if isa(A{1,1}, 'function_handle')
+                A{1,1} = A{1,1}(x_primal);
+                A{1,2} = A{1,2}(x_dual);
+                A{2,1} = A{2,1}(x_primal);
+                A{2,2} = A{2,2}(x_dual);
+            end
+
+            if isa(B{1,1}, 'function_handle')
+                B{1,1} = B{1,1}(x_primal);
+                B{1,2} = B{1,2}(x_primal);
+                B{2,1} = B{2,1}(x_dual);
+                B{2,2} = B{2,2}(x_dual);
+            end
+
+            % If coefficents are vectors, turn them into diagonal matrices
+            [m, n] = size(A{1,1});
+            if m==1 || n == 1
+                A{1,1} = spdiag(A{1,1}, 0);
+                A{2,1} = spdiag(A{2,1}, 0);
+                A{1,2} = spdiag(A{1,2}, 0);
+                A{2,2} = spdiag(A{2,2}, 0);
+            end
+
+            [m, n] = size(B{1,1});
+            if m==1 || n == 1
+                B{1,1} = spdiag(B{1,1}, 0);
+                B{2,1} = spdiag(B{2,1}, 0);
+                B{1,2} = spdiag(B{1,2}, 0);
+                B{2,2} = spdiag(B{2,2}, 0);
+            end
+
+            % Boundary matrices
+            obj.A_l = full([A{1,1}(1,1), A{1,2}(1,1);....
+                       A{2,1}(1,1), A{2,2}(1,1)]);
+            obj.A_r = full([A{1,1}(end,end), A{1,2}(end,end);....
+                       A{2,1}(end,end), A{2,2}(end,end)]);
+            obj.B_l = full([B{1,1}(1,1), B{1,2}(1,1);....
+                       B{2,1}(1,1), B{2,2}(1,1)]);
+            obj.B_r = full([B{1,1}(end,end), B{1,2}(end,end);....
+                       B{2,1}(end,end), B{2,2}(end,end)]);
+
+            % Get operators
+            ops = sbp.D1StaggeredUpwind(obj.m, xlim, order);
+            obj.h = ops.h;
+
+            % Build combined operators
+            H_primal = ops.H_primal;
+            H_dual = ops.H_dual;
+            obj.H = blockmatrix.toMatrix( {H_primal, []; [], H_dual } );
+            obj.Hi = inv(obj.H);
+
+            D1_primal = ops.D1_primal;
+            D1_dual = ops.D1_dual;
+            A11_B12 = -A{1,1}\B{1,2};
+            A22_B21 = -A{2,2}\B{2,1};
+            D = {[],                A11_B12*D1_primal;...
+                 A22_B21*D1_dual,     []};
+            obj.D = blockmatrix.toMatrix(D);
+            obj.D1_primal = D1_primal;
+            obj.D1_dual = D1_dual;
+
+            % Combined boundary operators
+            e_primal_l = ops.e_primal_l;
+            e_primal_r = ops.e_primal_r;
+            e_dual_l = ops.e_dual_l;
+            e_dual_r = ops.e_dual_r;
+            e_l = {e_primal_l, [];...
+                   []       ,  e_dual_l};
+            e_r = {e_primal_r, [];...
+                   []       ,  e_dual_r};
+            obj.e_l = blockmatrix.toMatrix(e_l);
+            obj.e_r = blockmatrix.toMatrix(e_r);
+
+            % Pick out first or second component of solution
+            N_primal = obj.grid_primal.N();
+            N_dual = obj.grid_dual.N();
+            obj.e_primal = [speye(N_primal, N_primal); sparse(N_dual, N_primal)];
+            obj.e_dual = [sparse(N_primal, N_dual); speye(N_dual, N_dual)];
+
+
+        end
+        % Closure functions return the operators applied to the own domain to close the boundary
+        % Penalty functions return the operators to force the solution. In the case of an interface it returns the operator applied to the other domain.
+        %       boundary            is a string specifying the boundary e.g. 'l','r' or 'e','w','n','s'.
+        %       type                is a string specifying the type of boundary condition if there are several.
+        %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
+        %       neighbour_boundary  is a string specifying which boundary to interface to.
+        function [closure, penalty] = boundary_condition(obj, boundary, type)
+
+            default_arg('type','p');
+
+            % type = 'p' => boundary condition for p
+            % type = 'v' => boundary condition for v
+            % No other types implemented yet
+
+            % BC on the form Lu - g = 0;
+
+            % Need a transformation T such that w = T^{−1}*u is a
+            % meaningful change of variables and T^T*B*T is block-diagonal,
+            % For linear acoustics, T = T_C meets these criteria.
+
+            % Get boundary matrices
+            switch boundary
+                case 'l'
+                    A = obj.A_l;
+                    B = obj.B_l;
+                case 'r'
+                    A = obj.A_r;
+                    B = obj.B_r;
+            end
+            C = inv(A)*B;
+
+            % Diagonalize C and use T_C to diagonalize B
+            [T, ~] = eig(C);
+            Lambda = T'*B*T;
+            lambda = diag(Lambda);
+
+            % Identify in- and outgoing characteristic variables
+            Iplus = lambda > 0;
+            Iminus = lambda < 0;
+
+            switch boundary
+            case 'l'
+                Iin = Iplus;
+            case 'r'
+                Iin = Iminus;
+            end
+            Tin = T(:,Iin);
+
+            switch type
+            case 'p'
+                L = [1, 0];
+            case 'v'
+                L = [0, 1];
+            case 'characteristic'
+                % Diagonalize C
+                [T_C, Lambda_C] = eig(C);
+                lambda_C = diag(Lambda_C);
+                % Identify in- and outgoing characteristic variables
+                Iplus = lambda_C > 0;
+                Iminus = lambda_C < 0;
+
+                switch boundary
+                case 'l'
+                    Iin_C = Iplus;
+                case 'r'
+                    Iin_C = Iminus;
+                end
+                T_C_inv = inv(T_C);
+                L = T_C_inv(Iin_C,:);
+            otherwise
+                error('Boundary condition not implemented.');
+            end
+
+            % Penalty parameters
+            sigma = [0; 0];
+            sigma(Iin) = lambda(Iin);
+
+            % Sparsify
+            A = sparse(A);
+            T = sparse(T);
+            sigma = sparse(sigma);
+            L = sparse(L);
+            Tin = sparse(Tin);
+
+            switch boundary
+            case 'l'
+                tau = -1*obj.e_l * inv(A) * inv(T)' * sigma * inv(L*Tin);
+                closure = obj.Hi*tau*L*obj.e_l';
+
+            case 'r'
+                tau = 1*obj.e_r * inv(A) * inv(T)' * sigma * inv(L*Tin);
+                closure = obj.Hi*tau*L*obj.e_r';
+
+            end
+
+            penalty = -obj.Hi*tau;
+
+         end
+
+         % Uses the hat variable method for the interface coupling,
+         % see hypsyst_varcoeff.pdf in the hypsyst repository.
+         % Notation: u for left side of interface, v for right side.
+         function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+
+            % Get boundary matrices
+            switch boundary
+                case 'l'
+                    A_v = obj.A_l;
+                    B_v = obj.B_l;
+                    Hi_v = obj.Hi;
+                    e_v = obj.e_l;
+
+                    A_u = neighbour_scheme.A_r;
+                    B_u = neighbour_scheme.B_r;
+                    Hi_u = neighbour_scheme.Hi;
+                    e_u = neighbour_scheme.e_r;
+                case 'r'
+                    A_u = obj.A_r;
+                    B_u = obj.B_r;
+                    Hi_u = obj.Hi;
+                    e_u = obj.e_r;
+
+                    A_v = neighbour_scheme.A_l;
+                    B_v = neighbour_scheme.B_l;
+                    Hi_v = neighbour_scheme.Hi;
+                    e_v = neighbour_scheme.e_l;
+            end
+            C_u = inv(A_u)*B_u;
+            C_v = inv(A_v)*B_v;
+
+            % Diagonalize C
+            [T_u, ~] = eig(C_u);
+            Lambda_u = inv(T_u)*C_u*T_u;
+            lambda_u = diag(Lambda_u);
+            S_u = inv(T_u);
+
+            [T_v, ~] = eig(C_v);
+            Lambda_v = inv(T_v)*C_v*T_v;
+            lambda_v = diag(Lambda_v);
+            S_v = inv(T_v);
+
+            % Identify in- and outgoing characteristic variables
+            Im_u = lambda_u < 0;
+            Ip_u = lambda_u > 0;
+            Im_v = lambda_v < 0;
+            Ip_v = lambda_v > 0;
+
+            Tp_u = T_u(:,Ip_u);
+            Tm_u = T_u(:,Im_u);
+            Sp_u = S_u(Ip_u,:);
+            Sm_u = S_u(Im_u,:);
+
+            Tp_v = T_v(:,Ip_v);
+            Tm_v = T_v(:,Im_v);
+            Sp_v = S_v(Ip_v,:);
+            Sm_v = S_v(Im_v,:);
+
+            % Create S_tilde and T_tilde
+            Stilde = [Sp_u; Sm_v];
+            Ttilde = inv(Stilde);
+            Ttilde_p = Ttilde(:,1);
+            Ttilde_m = Ttilde(:,2);
+
+            % Solve for penalty parameters theta_1,2
+            LHS = Ttilde_m*Sm_v*Tm_u;
+            RHS = B_u*Tm_u;
+            th_u = RHS./LHS;
+            TH_u = diag(th_u);
+
+            LHS = Ttilde_p*Sp_u*Tp_v;
+            RHS = -B_v*Tp_v;
+            th_v = RHS./LHS;
+            TH_v = diag(th_v);
+
+            % Construct penalty matrices
+            Z_u = TH_u*Ttilde_m*Sm_v;
+            Z_u = sparse(Z_u);
+
+            Z_v = TH_v*Ttilde_p*Sp_u;
+            Z_v = sparse(Z_v);
+
+            closure_u = Hi_u*e_u*Z_u*e_u';
+            penalty_u = -Hi_u*e_u*Z_u*e_v';
+            closure_v = Hi_v*e_v*Z_v*e_v';
+            penalty_v = -Hi_v*e_v*Z_v*e_u';
+
+             switch boundary
+                 case 'l'
+                     closure = closure_v;
+                     penalty = penalty_v;
+                 case 'r'
+                     closure = closure_u;
+                     penalty = penalty_u;
+             end
+
+         end
+
+        function N = size(obj)
+            N = 2*obj.m+1;
+        end
+
+    end
+
+    methods(Static)
+        % Calculates the matrices needed for the inteface coupling between boundary bound_u of scheme schm_u
+        % and bound_v of scheme schm_v.
+        %   [uu, uv, vv, vu] = inteface_coupling(A,'r',B,'l')
+        function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
+            [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
+            [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
+        end
+    end
+end
\ No newline at end of file
--- a/+scheme/Utux.m	Sat Nov 24 14:55:48 2018 +0000
+++ b/+scheme/Utux.m	Wed Nov 28 17:35:19 2018 -0800
@@ -2,7 +2,7 @@
    properties
         m % Number of points in each direction, possibly a vector
         h % Grid spacing
-        x % Grid
+        grid % Grid
         order % Order accuracy for the approximation
 
         H % Discrete norm
@@ -17,41 +17,40 @@
 
 
     methods 
-         function obj = Utux(m,xlim,order,operator)
-             default_arg('a',1);
-           
-           %Old operators  
-           % [x, h] = util.get_grid(xlim{:},m);
-           %ops = sbp.Ordinary(m,h,order);
-           
-           
+         function obj = Utux(g ,order, operator)
+             default_arg('operator','Standard');
+             
+             m = g.size();
+             xl = g.getBoundary('l');
+             xr = g.getBoundary('r');
+             xlim = {xl, xr};
+             
            switch operator
-               case 'NonEquidistant'
-              ops = sbp.D1Nonequidistant(m,xlim,order);
-              obj.D1 = ops.D1;
+%                case 'NonEquidistant'
+%               ops = sbp.D1Nonequidistant(m,xlim,order);
+%               obj.D1 = ops.D1;
                case 'Standard'
               ops = sbp.D2Standard(m,xlim,order);
               obj.D1 = ops.D1;
-               case 'Upwind'
-              ops = sbp.D1Upwind(m,xlim,order);
-              obj.D1 = ops.Dm;
+%                case 'Upwind'
+%               ops = sbp.D1Upwind(m,xlim,order);
+%               obj.D1 = ops.Dm;
                otherwise
                    error('Unvalid operator')
            end
-              obj.x=ops.x;
+           
+            obj.grid = g;
 
-            
             obj.H =  ops.H;
             obj.Hi = ops.HI;
         
             obj.e_l = ops.e_l;
             obj.e_r = ops.e_r;
-            obj.D=obj.D1;
+            obj.D = -obj.D1;
 
             obj.m = m;
             obj.h = ops.h;
             obj.order = order;
-            obj.x = ops.x;
 
         end
         % Closure functions return the opertors applied to the own doamin to close the boundary
@@ -61,17 +60,27 @@
         %       data                is a function returning the data that should be applied at the boundary.
         %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
         %       neighbour_boundary  is a string specifying which boundary to interface to.
-        function [closure, penalty] = boundary_condition(obj,boundary,type,data)
-            default_arg('type','neumann');
-            default_arg('data',0);
+        function [closure, penalty] = boundary_condition(obj,boundary,type)
+            default_arg('type','dirichlet');
             tau =-1*obj.e_l;  
             closure = obj.Hi*tau*obj.e_l';       
-            penalty = 0*obj.e_l;
+            penalty = -obj.Hi*tau;
                 
          end
           
          function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
-          error('An interface function does not exist yet');
+             switch boundary
+                 % Upwind coupling
+                 case {'l','left'}
+                     tau = -1*obj.e_l;
+                     closure = obj.Hi*tau*obj.e_l';       
+                     penalty = -obj.Hi*tau*neighbour_scheme.e_r';
+                 case {'r','right'}
+                     tau = 0*obj.e_r;
+                     closure = obj.Hi*tau*obj.e_r';       
+                     penalty = -obj.Hi*tau*neighbour_scheme.e_l';
+             end
+                 
          end
       
         function N = size(obj)
@@ -81,9 +90,9 @@
     end
 
     methods(Static)
-        % Calculates the matrcis need for the inteface coupling between boundary bound_u of scheme schm_u
+        % Calculates the matrices needed for the inteface coupling between boundary bound_u of scheme schm_u
         % and bound_v of scheme schm_v.
-        %   [uu, uv, vv, vu] = inteface_couplong(A,'r',B,'l')
+        %   [uu, uv, vv, vu] = inteface_coupling(A,'r',B,'l')
         function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
             [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
             [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+scheme/Utux2D.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,286 @@
+classdef Utux2D < scheme.Scheme
+   properties
+        m % Number of points in each direction, possibly a vector
+        h % Grid spacing
+        grid % Grid
+        order % Order accuracy for the approximation
+        v0 % Initial data
+        
+        a % Wave speed a = [a1, a2];
+          % Can either be a constant vector or a cell array of function handles.
+
+        H % Discrete norm
+        H_x, H_y % Norms in the x and y directions
+        Hi, Hx, Hy, Hxi, Hyi % Kroneckered norms
+
+        % Derivatives
+        Dx, Dy
+        
+        % Boundary operators
+        e_w, e_e, e_s, e_n
+        
+        D % Total discrete operator
+
+        % String, type of interface coupling
+        % Default: 'upwind'
+        % Other:   'centered'
+        coupling_type 
+
+        % String, type of interpolation operators
+        % Default: 'AWW' (Almquist Wang Werpers)
+        % Other:   'MC' (Mattsson Carpenter)
+        interpolation_type
+
+        
+        % Cell array, damping on upwstream and downstream sides.
+        interpolation_damping
+
+    end
+
+
+    methods 
+         function obj = Utux2D(g ,order, opSet, a, coupling_type, interpolation_type, interpolation_damping)
+            
+            default_arg('interpolation_damping',{0,0});
+            default_arg('interpolation_type','AWW'); 
+            default_arg('coupling_type','upwind'); 
+            default_arg('a',1/sqrt(2)*[1, 1]); 
+            default_arg('opSet',@sbp.D2Standard);
+
+            assert(isa(g, 'grid.Cartesian'))
+            if iscell(a)
+                a1 = grid.evalOn(g, a{1});
+                a2 = grid.evalOn(g, a{2});
+                a = {spdiag(a1), spdiag(a2)};
+            else
+                a = {a(1), a(2)};
+            end
+             
+            m = g.size();
+            m_x = m(1);
+            m_y = m(2);
+            m_tot = g.N();
+
+            xlim = {g.x{1}(1), g.x{1}(end)};
+            ylim = {g.x{2}(1), g.x{2}(end)};
+            obj.grid = g;
+
+            % Operator sets
+            ops_x = opSet(m_x, xlim, order);
+            ops_y = opSet(m_y, ylim, order);
+            Ix = speye(m_x);
+            Iy = speye(m_y);
+            
+            % Norms
+            Hx = ops_x.H;
+            Hy = ops_y.H;
+            Hxi = ops_x.HI;
+            Hyi = ops_y.HI;
+            
+            obj.H_x = Hx;
+            obj.H_y = Hy;
+            obj.H = kron(Hx,Hy);
+            obj.Hi = kron(Hxi,Hyi);
+            obj.Hx = kron(Hx,Iy);
+            obj.Hy = kron(Ix,Hy);
+            obj.Hxi = kron(Hxi,Iy);
+            obj.Hyi = kron(Ix,Hyi);
+            
+            % Derivatives
+            Dx = ops_x.D1;
+            Dy = ops_y.D1;
+            obj.Dx = kron(Dx,Iy);
+            obj.Dy = kron(Ix,Dy);
+           
+            % Boundary operators
+            obj.e_w = kr(ops_x.e_l, Iy);
+            obj.e_e = kr(ops_x.e_r, Iy);
+            obj.e_s = kr(Ix, ops_y.e_l);
+            obj.e_n = kr(Ix, ops_y.e_r);
+
+            obj.m = m;
+            obj.h = [ops_x.h ops_y.h];
+            obj.order = order;
+            obj.a = a;
+            obj.coupling_type = coupling_type;
+            obj.interpolation_type = interpolation_type;
+            obj.interpolation_damping = interpolation_damping;
+            obj.D = -(a{1}*obj.Dx + a{2}*obj.Dy);
+
+        end
+        % Closure functions return the opertors applied to the own domain to close the boundary
+        % Penalty functions return the opertors to force the solution. In the case of an interface it returns the operator applied to the other doamin.
+        %       boundary            is a string specifying the boundary e.g. 'l','r' or 'e','w','n','s'.
+        %       type                is a string specifying the type of boundary condition if there are several.
+        %       data                is a function returning the data that should be applied at the boundary.
+        %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
+        %       neighbour_boundary  is a string specifying which boundary to interface to.
+        function [closure, penalty] = boundary_condition(obj,boundary,type)
+            default_arg('type','dirichlet');
+            
+            sigma = -1; % Scalar penalty parameter
+            switch boundary
+                case {'w','W','west','West'}
+                    tau = sigma*obj.a{1}*obj.e_w*obj.H_y;
+                    closure = obj.Hi*tau*obj.e_w';
+                    
+                case {'s','S','south','South'}
+                    tau = sigma*obj.a{2}*obj.e_s*obj.H_x;
+                    closure = obj.Hi*tau*obj.e_s';
+            end  
+            penalty = -obj.Hi*tau;
+                
+         end
+          
+         function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+             
+             % Get neighbour boundary operator
+             switch neighbour_boundary
+                 case {'e','E','east','East'}
+                     e_neighbour = neighbour_scheme.e_e;
+                     m_neighbour = neighbour_scheme.m(2);
+                 case {'w','W','west','West'}
+                     e_neighbour = neighbour_scheme.e_w;
+                     m_neighbour = neighbour_scheme.m(2);
+                 case {'n','N','north','North'}
+                     e_neighbour = neighbour_scheme.e_n;
+                     m_neighbour = neighbour_scheme.m(1);
+                 case {'s','S','south','South'}
+                     e_neighbour = neighbour_scheme.e_s;
+                     m_neighbour = neighbour_scheme.m(1);
+             end
+             
+             switch obj.coupling_type
+             
+             % Upwind coupling (energy dissipation)
+             case 'upwind'
+                 sigma_ds = -1; %"Downstream" penalty
+                 sigma_us = 0; %"Upstream" penalty
+
+             % Energy-preserving coupling (no energy dissipation)
+             case 'centered'
+                 sigma_ds = -1/2; %"Downstream" penalty
+                 sigma_us = 1/2; %"Upstream" penalty
+
+             otherwise
+                error(['Interface coupling type ' coupling_type ' is not available.'])
+             end
+
+             % Check grid ratio for interpolation
+             switch boundary
+                 case {'w','W','west','West','e','E','east','East'}
+                     m = obj.m(2);       
+                 case {'s','S','south','South','n','N','north','North'}
+                     m = obj.m(1);
+             end
+             grid_ratio = m/m_neighbour;
+             if grid_ratio ~= 1
+
+                [ms, index] = sort([m, m_neighbour]);
+                orders = [obj.order, neighbour_scheme.order];
+                orders = orders(index);
+
+                switch obj.interpolation_type
+                case 'MC'
+                    interpOpSet = sbp.InterpMC(ms(1),ms(2),orders(1),orders(2));
+                    if grid_ratio < 1
+                        I_neighbour2local_us = interpOpSet.IF2C;
+                        I_neighbour2local_ds = interpOpSet.IF2C;
+                        I_local2neighbour_us = interpOpSet.IC2F;
+                        I_local2neighbour_ds = interpOpSet.IC2F;
+                    elseif grid_ratio > 1
+                        I_neighbour2local_us = interpOpSet.IC2F;
+                        I_neighbour2local_ds = interpOpSet.IC2F;
+                        I_local2neighbour_us = interpOpSet.IF2C;
+                        I_local2neighbour_ds = interpOpSet.IF2C;
+                    end
+                case 'AWW'
+                    %String 'C2F' indicates that ICF2 is more accurate.
+                    interpOpSetF2C = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'F2C');
+                    interpOpSetC2F = sbp.InterpAWW(ms(1),ms(2),orders(1),orders(2),'C2F'); 
+                    if grid_ratio < 1 
+                        % Local is coarser than neighbour
+                        I_neighbour2local_us = interpOpSetC2F.IF2C;
+                        I_neighbour2local_ds = interpOpSetF2C.IF2C;
+                        I_local2neighbour_us = interpOpSetC2F.IC2F;
+                        I_local2neighbour_ds = interpOpSetF2C.IC2F;
+                    elseif grid_ratio > 1
+                        % Local is finer than neighbour 
+                        I_neighbour2local_us = interpOpSetF2C.IC2F;
+                        I_neighbour2local_ds = interpOpSetC2F.IC2F;
+                        I_local2neighbour_us = interpOpSetF2C.IF2C;
+                        I_local2neighbour_ds = interpOpSetC2F.IF2C;
+                    end
+                otherwise
+                    error(['Interpolation type ' obj.interpolation_type ...
+                         ' is not available.' ]);
+                end
+
+             else 
+                % No interpolation required
+                I_neighbour2local_us = speye(m,m);
+                I_neighbour2local_ds = speye(m,m);
+            end    
+             
+             int_damp_us = obj.interpolation_damping{1};
+             int_damp_ds = obj.interpolation_damping{2};
+
+             I = speye(m,m);
+             I_back_forth_us = I_neighbour2local_us*I_local2neighbour_us;
+             I_back_forth_ds = I_neighbour2local_ds*I_local2neighbour_ds;
+
+
+             switch boundary
+                 case {'w','W','west','West'}
+                     tau = sigma_ds*obj.a{1}*obj.e_w*obj.H_y;
+                     closure = obj.Hi*tau*obj.e_w';
+                     penalty = -obj.Hi*tau*I_neighbour2local_ds*e_neighbour';
+
+                     beta = int_damp_ds*obj.a{1}...
+                            *obj.e_w*obj.H_y;
+                     closure = closure + obj.Hi*beta*(I_back_forth_ds - I)*obj.e_w';     
+                 case {'e','E','east','East'}
+                     tau = sigma_us*obj.a{1}*obj.e_e*obj.H_y;
+                     closure = obj.Hi*tau*obj.e_e';
+                     penalty = -obj.Hi*tau*I_neighbour2local_us*e_neighbour';
+
+                     beta = int_damp_us*obj.a{1}...
+                            *obj.e_e*obj.H_y;
+                     closure = closure + obj.Hi*beta*(I_back_forth_us - I)*obj.e_e'; 
+                 case {'s','S','south','South'}
+                     tau = sigma_ds*obj.a{2}*obj.e_s*obj.H_x;
+                     closure = obj.Hi*tau*obj.e_s'; 
+                     penalty = -obj.Hi*tau*I_neighbour2local_ds*e_neighbour';
+
+                     beta = int_damp_ds*obj.a{2}...
+                            *obj.e_s*obj.H_x;
+                     closure = closure + obj.Hi*beta*(I_back_forth_ds - I)*obj.e_s';
+                 case {'n','N','north','North'}
+                     tau = sigma_us*obj.a{2}*obj.e_n*obj.H_x;
+                     closure = obj.Hi*tau*obj.e_n';
+                     penalty = -obj.Hi*tau*I_neighbour2local_us*e_neighbour';
+
+                     beta = int_damp_us*obj.a{2}...
+                            *obj.e_n*obj.H_x;
+                     closure = closure + obj.Hi*beta*(I_back_forth_us - I)*obj.e_n'; 
+             end
+             
+                 
+         end
+      
+        function N = size(obj)
+            N = obj.m;
+        end
+
+    end
+
+    methods(Static)
+        % Calculates the matrices needed for the inteface coupling between boundary bound_u of scheme schm_u
+        % and bound_v of scheme schm_v.
+        %   [uu, uv, vv, vu] = inteface_coupling(A,'r',B,'l')
+        function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
+            [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
+            [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
+        end
+    end
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+time/+rkparameters/rk4.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,12 @@
+function [a,b,c,s] = rk4()
+
+% Butcher tableau for classical RK$
+s = 4;
+a = sparse(s,s);
+a(2,1) = 1/2;
+a(3,2) = 1/2;
+a(4,3) = 1;
+b = 1/6*[1; 2; 2; 1];
+c = [0; 1/2; 1/2; 1];
+
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+time/ExplicitRungeKuttaDiscreteData.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,121 @@
+classdef ExplicitRungeKuttaDiscreteData < time.Timestepper
+    properties
+        D
+        S           % Function handle for time-dependent data
+        data        % Matrix of data vectors, one column per stage
+        k
+        t
+        v
+        m
+        n
+        order
+        a, b, c, s  % Butcher tableau
+        K           % Stage rates
+        U           % Stage approximations
+        T           % Stage times
+    end
+
+
+    methods
+        function obj = ExplicitRungeKuttaDiscreteData(D, S, data, k, t0, v0, order)
+            default_arg('order', 4);
+            default_arg('S', []);
+            default_arg('data', []);
+
+            obj.D = D;
+            obj.S = S;
+            obj.k = k;
+            obj.t = t0;
+            obj.v = v0;
+            obj.m = length(v0);
+            obj.n = 0;
+            obj.order = order;
+            obj.data = data;
+
+            switch order
+            case 4
+                [obj.a, obj.b, obj.c, obj.s] = time.rkparameters.rk4();
+            otherwise
+                error('That RK method is not available');
+            end
+
+            obj.K = sparse(obj.m, obj.s);
+            obj.U = sparse(obj.m, obj.s);
+
+        end
+
+        function [v,t,U,T,K] = getV(obj)
+            v = obj.v;
+            t = obj.t;
+            U = obj.U; % Stage approximations in previous time step.
+            T = obj.T; % Stage times in previous time step.
+            K = obj.K; % Stage rates in previous time step.
+        end
+
+        function [a,b,c,s] = getTableau(obj)
+            a = obj.a;
+            b = obj.b;
+            c = obj.c;
+            s = obj.s;
+        end
+
+        % Returns quadrature weights for stages in one time step
+        function quadWeights = getTimeStepQuadrature(obj)
+            [~, b] = obj.getTableau();
+            quadWeights = obj.k*b;
+        end
+
+        function obj = step(obj)
+            v = obj.v;
+            a = obj.a;
+            b = obj.b;
+            c = obj.c;
+            s = obj.s;
+            S = obj.S;
+            dt = obj.k;
+            K = obj.K;
+            U = obj.U;
+            D = obj.D;
+            data = obj.data;
+
+            for i = 1:s
+                U(:,i) = v;
+                for j = 1:i-1
+                    U(:,i) = U(:,i) + dt*a(i,j)*K(:,j);
+                end
+
+                K(:,i) = D*U(:,i);
+                obj.T(i) = obj.t + c(i)*dt;
+
+                % Data from continuous function and discrete time-points.
+                if ~isempty(S)
+                    K(:,i) = K(:,i) + S(obj.T(i));
+                end
+                if ~isempty(data)
+                    K(:,i) = K(:,i) + data(:,obj.n*s + i);
+                end
+
+            end
+
+            obj.v = v + dt*K*b;
+            obj.t = obj.t + dt;
+            obj.n = obj.n + 1;
+            obj.U = U;
+            obj.K = K;
+        end
+    end
+
+
+    methods (Static)
+        function k = getTimeStep(lambda, order)
+            default_arg('order', 4);
+            switch order
+            case 4
+                k = time.rk4.get_rk4_time_step(lambda);
+            otherwise
+                error('Time-step function not available for this order');
+            end
+        end
+    end
+
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+time/ExplicitRungeKuttaSecondOrderDiscreteData.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,129 @@
+classdef ExplicitRungeKuttaSecondOrderDiscreteData < time.Timestepper
+    properties
+        k
+        t
+        w
+        m
+        D
+        E
+        M
+        C_cont % Continuous part (function handle) of forcing on first order form.
+        C_discr% Discrete part (matrix) of forcing on first order form.
+        n
+        order
+        tsImplementation % Time stepper object, RK first order form,
+                         % which this wraps around.
+    end
+
+
+    methods
+        % Solves u_tt = Du + Eu_t + S by
+        % Rewriting on first order form:
+        %   w_t = M*w + C(t)
+        % where
+        %   M = [
+        %      0, I;
+        %      D, E;
+        %   ]
+        % and
+        %   C(t) = [
+        %      0;
+        %      S(t)
+        %   ]
+        % D, E, should be matrices (or empty for zero)
+        % They can also be omitted by setting them equal to the empty matrix.
+        % S = S_cont + S_discr, where S_cont is a function handle
+        % S_discr a matrix of data vectors, one column per stage.
+        function obj = ExplicitRungeKuttaSecondOrderDiscreteData(D, E, S_cont, S_discr, k, t0, v0, v0t, order)
+            default_arg('order', 4);
+            default_arg('S_cont', []);
+            default_arg('S_discr', []);
+            obj.D = D;
+            obj.E = E;
+            obj.m = length(v0);
+            obj.n = 0;
+
+            default_arg('D', sparse(obj.m, obj.m) );
+            default_arg('E', sparse(obj.m, obj.m) );
+
+            obj.k = k;
+            obj.t = t0;
+            obj.w = [v0; v0t];
+
+            I = speye(obj.m);
+            O = sparse(obj.m,obj.m);
+
+            obj.M = [
+                O, I;
+                D, E;
+            ];
+
+            % Build C_cont
+            if ~isempty(S_cont)
+                obj.C_cont = @(t)[
+                    sparse(obj.m,1);
+                    S_cont(t)
+                            ];
+            else
+                obj.C_cont = [];
+            end
+
+            % Build C_discr
+            if ~isempty(S_discr)
+                [~, nt] = size(S_discr);
+                obj.C_discr = [sparse(obj.m, nt);
+                                S_discr
+                ];
+            else
+                obj.C_discr = [];
+            end
+            obj.tsImplementation = time.ExplicitRungeKuttaDiscreteData(obj.M, obj.C_cont, obj.C_discr,...
+                                                                        k, obj.t, obj.w, order);
+        end
+
+        function [v,t,U,T,K] = getV(obj)
+            [w,t,U,T,K] = obj.tsImplementation.getV();
+
+            v = w(1:end/2);
+            U = U(1:end/2, :); % Stage approximations in previous time step.
+            K = K(1:end/2, :); % Stage rates in previous time step.
+            % T: Stage times in previous time step.
+        end
+
+        function [vt,t,U,T,K] = getVt(obj)
+            [w,t,U,T,K] = obj.tsImplementation.getV();
+
+            vt = w(end/2+1:end);
+            U = U(end/2+1:end, :); % Stage approximations in previous time step.
+            K = K(end/2+1:end, :); % Stage rates in previous time step.
+            % T: Stage times in previous time step.
+        end
+
+        function [a,b,c,s] = getTableau(obj)
+            [a,b,c,s] = obj.tsImplementation.getTableau();
+        end
+
+        % Returns quadrature weights for stages in one time step
+        function quadWeights = getTimeStepQuadrature(obj)
+            [~, b] = obj.getTableau();
+            quadWeights = obj.k*b;
+        end
+
+        % Use RK for first order form to step
+        function obj = step(obj)
+            obj.tsImplementation.step();
+            [v, t] = obj.tsImplementation.getV();
+            obj.w = v;
+            obj.t = t;
+            obj.n = obj.n + 1;
+        end
+    end
+
+    methods (Static)
+        function k = getTimeStep(lambda, order)
+            default_arg('order', 4);
+            k = obj.tsImplementation.getTimeStep(lambda, order);
+        end
+    end
+
+end
\ No newline at end of file
--- a/.hgtags	Sat Nov 24 14:55:48 2018 +0000
+++ b/.hgtags	Wed Nov 28 17:35:19 2018 -0800
@@ -2,3 +2,4 @@
 0776fa4754ff0c1918f6e1278c66f48c62d05736 grids0.1
 b723495cdb2f96314d7b3f0aa79723a7dc088c7d v0.2
 08f3ffe63f484d02abce8df4df61e826f568193f elastic1.0
+08f3ffe63f484d02abce8df4df61e826f568193f Heimisson2018
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/diracDiscr.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,130 @@
+
+function d = diracDiscr(x_s, x, m_order, s_order, H)
+    % n-dimensional delta function
+    % x_s: source point coordinate vector, e.g. [x, y] or [x, y, z].
+    % x: cell array of grid point column vectors for each dimension.
+    % m_order: Number of moment conditions
+    % s_order: Number of smoothness conditions
+    % H: cell array of 1D norm matrices
+
+    dim = length(x_s);
+    d_1D = cell(dim,1);
+
+    % If 1D, non-cell input is accepted
+    if dim == 1 && ~iscell(x)
+        d = diracDiscr1D(x_s, x, m_order, s_order, H);
+
+    else
+        for i = 1:dim
+            d_1D{i} = diracDiscr1D(x_s(i), x{i}, m_order, s_order, H{i});
+        end
+
+        d = d_1D{dim};
+        for i = dim-1: -1: 1
+            % Perform outer product, transpose, and then turn into column vector
+            d = (d_1D{i}*d')';
+            d = d(:);
+        end
+    end
+
+end
+
+
+% Helper function for 1D delta functions
+function ret = diracDiscr1D(x_0in , x , m_order, s_order, H)
+
+m = length(x);
+
+% Return zeros if x0 is outside grid
+if(x_0in < x(1) || x_0in > x(end) )
+
+    ret = zeros(size(x));
+
+else
+
+    fnorm = diag(H);
+    eta = abs(x-x_0in);
+    tot = m_order+s_order;
+    S = [];
+    M = [];
+
+    % Get interior grid spacing
+    middle = floor(m/2);
+    h = x(middle+1) - x(middle);
+
+    poss = find(tot*h/2 >= eta);
+
+    % Ensure that poss is not too long
+    if length(poss) == (tot + 2)
+        poss = poss(2:end-1);
+    elseif length(poss) == (tot + 1)
+        poss = poss(1:end-1);
+    end
+
+    % Use first tot grid points
+    if length(poss)<tot && x_0in < x(1) + ceil(tot/2)*h;
+        index=1:tot;
+        pol=(x(1:tot)-x(1))/(x(tot)-x(1));
+        x_0=(x_0in-x(1))/(x(tot)-x(1));
+        norm=fnorm(1:tot)/h;
+
+    % Use last tot grid points
+    elseif length(poss)<tot && x_0in > x(end) - ceil(tot/2)*h;
+        index = length(x)-tot+1:length(x);
+        pol = (x(end-tot+1:end)-x(end-tot+1))/(x(end)-x(end-tot+1));
+        norm = fnorm(end-tot+1:end)/h;
+        x_0 = (x_0in-x(end-tot+1))/(x(end)-x(end-tot+1));
+
+    % Interior, compensate for round-off errors.
+    elseif length(poss) < tot
+        if poss(end)<m
+            poss = [poss; poss(end)+1];
+        else
+            poss = [poss(1)-1; poss];
+        end
+        pol = (x(poss)-x(poss(1)))/(x(poss(end))-x(poss(1)));
+        x_0 = (x_0in-x(poss(1)))/(x(poss(end))-x(poss(1)));
+        norm = fnorm(poss)/h;
+        index = poss;
+
+    % Interior
+    else
+        pol = (x(poss)-x(poss(1)))/(x(poss(end))-x(poss(1)));
+        x_0 = (x_0in-x(poss(1)))/(x(poss(end))-x(poss(1)));
+        norm = fnorm(poss)/h;
+        index = poss;
+    end
+
+    h_pol = pol(2)-pol(1);
+    b = zeros(m_order+s_order,1);
+
+    for i = 1:m_order
+        b(i,1) = x_0^(i-1);
+    end
+
+    for i = 1:(m_order+s_order)
+        for j = 1:m_order
+            M(j,i) = pol(i)^(j-1)*h_pol*norm(i);
+        end
+    end
+
+    for i = 1:(m_order+s_order)
+        for j = 1:s_order
+            S(j,i) = (-1)^(i-1)*pol(i)^(j-1);
+        end
+    end
+
+    A = [M;S];
+
+    d = A\b;
+    ret = x*0;
+    ret(index) = d/h*h_pol;
+end
+
+end
+
+
+
+
+
+
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/diracDiscrTest.m	Wed Nov 28 17:35:19 2018 -0800
@@ -0,0 +1,595 @@
+function tests = diracDiscrTest()
+	    tests = functiontests(localfunctions);
+end
+
+function testLeftGP(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test left boundary grid points
+        x0s = xl + [0, h, 2*h];
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testLeftRandom(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test random points near left boundary
+        x0s = xl + 2*h*rand(1,10);
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testRightGP(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test right boundary grid points
+        x0s = xr-[0, h, 2*h];
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testRightRandom(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test random points near right boundary
+        x0s = xr - 2*h*rand(1,10);
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testInteriorGP(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test interior grid points
+        m_half = round(m/2);
+        x0s = xl + (m_half-1:m_half+1)*h;
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testInteriorRandom(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test random points in interior
+        x0s = (xl+2*h) + (xr-xl-4*h)*rand(1,20);
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+% x0 outside grid should yield 0 integral!
+function testX0OutsideGrid(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test points outisde grid
+        x0s = [xl-1.1*h, xr+1.1*h];
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - 0);
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testAllGP(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test all grid points
+        x0s = x;
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testHalfGP(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond);
+
+        % Test halfway between all grid points
+        x0s = 1/2*( x(2:end)+x(1:end-1) );
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(x);
+            for i = 1:length(x0s)
+                x0 = x0s(i);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H*fx;
+                err = abs(integral - f(x0));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+% function testAllGPStaggered(testCase)
+
+%     orders = [2, 4, 6];
+%     mom_conds = orders;
+
+%     for o = 1:length(orders)
+%         order = orders(o);
+%         mom_cond = mom_conds(o);
+%         [xl, xr, m, h, x, H, fs] = setupStaggered(order, mom_cond);
+
+%         % Test all grid points
+%         x0s = x;
+
+%         for j = 1:length(fs)
+%                 f = fs{j};
+%                 fx = f(x);
+%             for i = 1:length(x0s)
+%                 x0 = x0s(i);
+%                 delta = diracDiscr(x0, x, mom_cond, 0, H);
+%                 integral = delta'*H*fx;
+%                 err = abs(integral - f(x0));
+%                 testCase.verifyLessThan(err, 1e-12);
+%             end
+%         end
+%     end
+% end
+
+% function testHalfGPStaggered(testCase)
+
+%     orders = [2, 4, 6];
+%     mom_conds = orders;
+
+%     for o = 1:length(orders)
+%         order = orders(o);
+%         mom_cond = mom_conds(o);
+%         [xl, xr, m, h, x, H, fs] = setupStaggered(order, mom_cond);
+
+%         % Test halfway between all grid points
+%         x0s = 1/2*( x(2:end)+x(1:end-1) );
+
+%         for j = 1:length(fs)
+%                 f = fs{j};
+%                 fx = f(x);
+%             for i = 1:length(x0s)
+%                 x0 = x0s(i);
+%                 delta = diracDiscr(x0, x, mom_cond, 0, H);
+%                 integral = delta'*H*fx;
+%                 err = abs(integral - f(x0));
+%                 testCase.verifyLessThan(err, 1e-12);
+%             end
+%         end
+%     end
+% end
+
+% function testRandomStaggered(testCase)
+
+%     orders = [2, 4, 6];
+%     mom_conds = orders;
+
+%     for o = 1:length(orders)
+%         order = orders(o);
+%         mom_cond = mom_conds(o);
+%         [xl, xr, m, h, x, H, fs] = setupStaggered(order, mom_cond);
+
+%         % Test random points within grid boundaries
+%         x0s = xl + (xr-xl)*rand(1,300);
+
+%         for j = 1:length(fs)
+%                 f = fs{j};
+%                 fx = f(x);
+%             for i = 1:length(x0s)
+%                 x0 = x0s(i);
+%                 delta = diracDiscr(x0, x, mom_cond, 0, H);
+%                 integral = delta'*H*fx;
+%                 err = abs(integral - f(x0));
+%                 testCase.verifyLessThan(err, 1e-12);
+%             end
+%         end
+%     end
+% end
+
+%=============== 2D tests ==============================
+function testAllGP2D(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xlims, ylims, m, x, X, ~, H, fs] = setup2D(order, mom_cond);
+        H_global = kron(H{1}, H{2});
+
+        % Test all grid points
+        x0s = X;
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(X(:,1), X(:,2));
+            for i = 1:length(x0s)
+                x0 = x0s(i,:);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H_global*fx;
+                err = abs(integral - f(x0(1), x0(2)));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testAllRandom2D(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xlims, ylims, m, x, X, h, H, fs] = setup2D(order, mom_cond);
+        H_global = kron(H{1}, H{2});
+
+        xl = xlims{1};
+        xr = xlims{2};
+        yl = ylims{1};
+        yr = ylims{2};
+
+        % Test random points, even outside grid
+        Npoints = 100;
+        x0s = [(xl-3*h{1}) + (xr-xl+6*h{1})*rand(Npoints,1), ...
+               (yl-3*h{2}) + (yr-yl+6*h{2})*rand(Npoints,1) ];
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(X(:,1), X(:,2));
+            for i = 1:length(x0s)
+                x0 = x0s(i,:);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H_global*fx;
+
+                % Integral should be 0 if point is outside grid
+                if x0(1) < xl || x0(1) > xr || x0(2) < yl || x0(2) > yr
+                    err = abs(integral - 0);
+                else
+                    err = abs(integral - f(x0(1), x0(2)));
+                end
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+%=============== 3D tests ==============================
+function testAllGP3D(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xlims, ylims, zlims, m, x, X, h, H, fs] = setup3D(order, mom_cond);
+        H_global = kron(kron(H{1}, H{2}), H{3});
+
+        % Test all grid points
+        x0s = X;
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(X(:,1), X(:,2), X(:,3));
+            for i = 1:length(x0s)
+                x0 = x0s(i,:);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H_global*fx;
+                err = abs(integral - f(x0(1), x0(2), x0(3)));
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+function testAllRandom3D(testCase)
+
+    orders = [2, 4, 6];
+    mom_conds = orders;
+
+    for o = 1:length(orders)
+        order = orders(o);
+        mom_cond = mom_conds(o);
+        [xlims, ylims, zlims, m, x, X, h, H, fs] = setup3D(order, mom_cond);
+        H_global = kron(kron(H{1}, H{2}), H{3});
+
+        xl = xlims{1};
+        xr = xlims{2};
+        yl = ylims{1};
+        yr = ylims{2};
+        zl = zlims{1};
+        zr = zlims{2};
+
+        % Test random points, even outside grid
+        Npoints = 200;
+        x0s = [(xl-3*h{1}) + (xr-xl+6*h{1})*rand(Npoints,1), ...
+               (yl-3*h{2}) + (yr-yl+6*h{2})*rand(Npoints,1), ...
+               (zl-3*h{3}) + (zr-zl+6*h{3})*rand(Npoints,1) ];
+
+        for j = 1:length(fs)
+                f = fs{j};
+                fx = f(X(:,1), X(:,2), X(:,3));
+            for i = 1:length(x0s)
+                x0 = x0s(i,:);
+                delta = diracDiscr(x0, x, mom_cond, 0, H);
+                integral = delta'*H_global*fx;
+
+                % Integral should be 0 if point is outside grid
+                if x0(1) < xl || x0(1) > xr || x0(2) < yl || x0(2) > yr || x0(3) < zl || x0(3) > zr
+                    err = abs(integral - 0);
+                else
+                    err = abs(integral - f(x0(1), x0(2), x0(3)));
+                end
+                testCase.verifyLessThan(err, 1e-12);
+            end
+        end
+    end
+end
+
+
+% ======================================================
+% ============== Setup functions =======================
+% ======================================================
+function [xl, xr, m, h, x, H, fs] = setup1D(order, mom_cond)
+
+    % Grid
+    xl = -3;
+    xr = 900;
+    L = xr-xl;
+    m = 101;
+    h = (xr-xl)/(m-1);
+    g = grid.equidistant(m, {xl, xr});
+    x = g.points();
+
+    % Quadrature
+    ops = sbp.D2Standard(m, {xl, xr}, order);
+    H = ops.H;
+
+    % Moment conditions
+    fs = cell(mom_cond,1);
+    for p = 0:mom_cond-1
+        fs{p+1} = @(x) (x/L).^p;
+    end
+
+end
+
+function [xlims, ylims, m, x, X, h, H, fs] = setup2D(order, mom_cond)
+
+    % Grid
+    xlims = {-3, 20};
+    ylims = {-11,5};
+    Lx = xlims{2} - xlims{1};
+    Ly = ylims{2} - ylims{1};
+
+    m = [15, 16];
+    g = grid.equidistant(m, xlims, ylims);
+    X = g.points();
+    x = g.x;
+
+    % Quadrature
+    opsx = sbp.D2Standard(m(1), xlims, order);
+    opsy = sbp.D2Standard(m(2), ylims, order);
+    Hx = opsx.H;
+    Hy = opsy.H;
+    H = {Hx, Hy};
+
+    % Moment conditions
+    fs = cell(mom_cond,1);
+    for p = 0:mom_cond-1
+        fs{p+1} = @(x,y) (x/Lx + y/Ly).^p;
+    end
+
+    % Grid spacing in interior
+    mm = round(m/2);
+    hx = x{1}(mm(1)+1) - x{1}(mm(1));
+    hy = x{2}(mm(2)+1) - x{2}(mm(2));
+    h = {hx, hy};
+
+end
+
+function [xlims, ylims, zlims, m, x, X, h, H, fs] = setup3D(order, mom_cond)
+
+    % Grid
+    xlims = {-3, 20};
+    ylims = {-11,5};
+    zlims = {2,4};
+    Lx = xlims{2} - xlims{1};
+    Ly = ylims{2} - ylims{1};
+    Lz = zlims{2} - zlims{1};
+
+    m = [13, 14, 15];
+    g = grid.equidistant(m, xlims, ylims, zlims);
+    X = g.points();
+    x = g.x;
+
+    % Quadrature
+    opsx = sbp.D2Standard(m(1), xlims, order);
+    opsy = sbp.D2Standard(m(2), ylims, order);
+    opsz = sbp.D2Standard(m(3), zlims, order);
+    Hx = opsx.H;
+    Hy = opsy.H;
+    Hz = opsz.H;
+    H = {Hx, Hy, Hz};
+
+    % Moment conditions
+    fs = cell(mom_cond,1);
+    for p = 0:mom_cond-1
+        fs{p+1} = @(x,y,z) (x/Lx + y/Ly + z/Lz).^p;
+    end
+
+    % Grid spacing in interior
+    mm = round(m/2);
+    hx = x{1}(mm(1)+1) - x{1}(mm(1));
+    hy = x{2}(mm(2)+1) - x{2}(mm(2));
+    hz = x{3}(mm(3)+1) - x{3}(mm(3));
+    h = {hx, hy, hz};
+
+end
+
+function [xl, xr, m, h, x, H, fs] = setupStaggered(order, mom_cond)
+
+    % Grid
+    xl = -3;
+    xr = 900;
+    L = xr-xl;
+    m = 101;
+    [~, g_dual] = grid.primalDual1D(m, {xl, xr});
+    x = g_dual.points();
+    h = g_dual.h;
+
+    % Quadrature
+    ops = sbp.D1Staggered(m, {xl, xr}, order);
+    H = ops.H_dual;
+
+    % Moment conditions
+    fs = cell(mom_cond,1);
+    for p = 0:mom_cond-1
+        fs{p+1} = @(x) (x/L).^p;
+    end
+
+end