--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+multiblock/DiffOp.m	Thu Mar 03 20:03:06 2016 +0100
@@ -0,0 +1,121 @@
+classdef DiffOp < scheme.Scheme
+    properties
+        grid
+        order
+        diffOps
+        D
+        H
+    end
+
+    methods
+        function obj = DiffOp(doHand, grid, order, doParam)
+            %  doHand -- may either be a function handle or a cell array of
+            %            function handles for each grid. The function handle(s)
+            %            should be on the form do = doHand(grid, order, ...)
+            %            Additional parameters for each doHand may be provided in
+            %            the doParam input.
+            %    grid -- a multiblock grid
+            %   order -- integer specifying the order of accuracy
+            % doParam -- may either be a cell array or a cell array of cell arrays
+            %            for each block. If it is a cell array with length equal
+            %            to the number of blocks then each element is sent to the
+            %            corresponding function handle as extra parameters:
+            %            doHand(..., doParam{i}{:}) Otherwise doParam is sent as
+            %            extra parameters to all doHand: doHand(..., doParam{:})
+            default_arg('doParam', [])
+
+            [getHand, getParam] = parseInput(doHand, grid, doParam);
+
+            nBlocks = grid.nBlocks();
+
+            obj.order = order;
+
+            % Create the diffOps for each block
+            obj.diffOps = cell(1, nBlocks);
+            for i = 1:nBlocks
+                h = getHand(i);
+                p = getParam(i);
+                obj.diffOps{i} = h(grid.grid{i}, order, p{:});
+            end
+
+
+            % Build the norm matrix
+            H = cell(nBlocks, nBlocks);
+            for i = 1:nBlocks
+                H{i,i} = obj.diffOps{i}.H;
+            end
+            obj.H = cell2sparse(H);
+
+
+            % Build the differentiation matrix
+            D = cell(nBlocks, nBlocks);
+            for i = 1:nBlocks
+                D{i,i} = obj.diffOps{i}.D;
+            end
+
+            for i = 1:nBlocks
+                for j = i:nBlocks
+                    intf = grid.connections{i,j};
+                    if isempty(intf)
+                        continue
+                    end
+
+                    [ii, ij] = obj.diffOps{i}.inteface_coupling(intf{1}, obj.diffOps{j}, intf{2});
+                    D{i,i} = D{i,i} + ii;
+                    D{i,j} = D{i,j} + ij;
+
+                    [jj, ji] = obj.diffOps{j}.inteface_coupling(intf{2}, obj.diffOps{i}, intf{1});
+                    D{j,j} = D{j,j} + jj;
+                    D{j,i} = D{j,i} + ji;
+                end
+            end
+            obj.D = cell2sparse(D);
+
+            % end
+
+            function [getHand, getParam] = parseInput(doHand, grid, doParam)
+                if ~isa(grid, 'multiblock.Grid')
+                    error('multiblock:DiffOp:DiffOp:InvalidGrid', 'Requires a multiblock grid.');
+                end
+
+                if iscell(doHand) && length(doHand) == grid.nBlocks()
+                    getHand = @(i)doHand{i};
+                elseif isa(doHand, 'function_handle')
+                    getHand = @(i)doHand;
+                else
+                    error('multiblock:DiffOp:DiffOp:InvalidGridDoHand', 'doHand must be a function handle or a cell array of length grid.nBlocks');
+                end
+
+                if isempty(doParam)
+                    getParam = @(i){};
+                elseif iscell(doParam) && length(doParam) == grid.nBlocks()
+                    getParam = @(i)doParam{i};
+                else
+                    getParam = @(i)doParam;
+                end
+            end
+        end
+
+        function ops = splitOp(obj, op)
+            % Splits a matrix operator into a cell-matrix of matrix operators for
+            % each grid.
+            ops = sparse2cell(op, obj.NNN);
+        end
+
+        function m = boundary_condition(obj,boundary,type,data)
+
+        end
+
+        function m = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+
+        end
+
+
+        function N = size(obj)
+            N = 0;
+            for i = 1:length(diffOps)
+                N = N + diffOps.size();
+            end
+        end
+    end
+end