changeset 1286:4cb627c7fb90 feature/boundary_optimized_grids

Make D1Nonequidistant use the grid generation functions accurate/minimalBoundaryOptimizedGrid and remove grid generation from +implementations
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Wed, 01 Jul 2020 13:43:32 +0200
parents 6b68f939d023
children 38653d26225c
files +sbp/+implementations/d1_noneq_10.m +sbp/+implementations/d1_noneq_12.m +sbp/+implementations/d1_noneq_4.m +sbp/+implementations/d1_noneq_6.m +sbp/+implementations/d1_noneq_8.m +sbp/+implementations/d1_noneq_minimal_10.m +sbp/+implementations/d1_noneq_minimal_12.m +sbp/+implementations/d1_noneq_minimal_4.m +sbp/+implementations/d1_noneq_minimal_6.m +sbp/+implementations/d1_noneq_minimal_8.m +sbp/D1Nonequidistant.m
diffstat 11 files changed, 54 insertions(+), 516 deletions(-) [+]
line wrap: on
line diff
--- a/+sbp/+implementations/d1_noneq_10.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_10.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,48 +1,12 @@
-function [D1,H,x,h] = d1_noneq_10(N,L)
+function [D1,H] = d1_noneq_10(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<20)
     error('Operator requires at least 20 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 10;
-m = 5;
-order = 10;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  3.5902433622052e-01;
-x2 =  1.1436659188355e+00;
-x3 =  2.2144895894456e+00;
-x4 =  3.3682742337736e+00;
-x5 =  4.4309689056870e+00;
-x6 =  5.4309689056870e+00;
-x7 =  6.4309689056870e+00;
-x8 =  7.4309689056870e+00;
-x9 =  8.4309689056870e+00;
-x10 =  9.4309689056870e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -69,22 +33,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 10;
+d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_12.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_12.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,50 +1,12 @@
-function [D1,H,x,h] = d1_noneq_12(N,L)
+function [D1,H] = d1_noneq_12(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<24)
     error('Operator requires at least 24 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 12;
-m = 6;
-order = 12;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  3.6098032343909e-01;
-x2 =  1.1634317168086e+00;
-x3 =  2.2975905356987e+00;
-x4 =  3.6057529790929e+00;
-x5 =  4.8918275675510e+00;
-x6 =  6.0000000000000e+00;
-x7 =  7.0000000000000e+00;
-x8 =  8.0000000000000e+00;
-x9 =  9.0000000000000e+00;
-x10 =  1.0000000000000e+01;
-x11 =  1.1000000000000e+01;
-x12 =  1.2000000000000e+01;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -73,22 +35,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 12;
+d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_4.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_4.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,42 +1,12 @@
-function [D1,H,x,h] = d1_noneq_4(N,L)
+function [D1,H] = d1_noneq_4(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<8)
     error('Operator requires at least 8 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 4;
-m = 2;
-order = 4;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  6.8764546205559e-01;
-x2 =  1.8022115125776e+00;
-x3 =  2.8022115125776e+00;
-x4 =  3.8022115125776e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -57,22 +27,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 4;
+d = [1/12,-2/3,0,2/3,-1/12];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_6.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_6.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,44 +1,12 @@
-function [D1,H,x,h] = d1_noneq_6(N,L)
+function [D1,H] = d1_noneq_6(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<12)
     error('Operator requires at least 12 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 6;
-m = 3;
-order = 6;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  4.4090263368623e-01;
-x2 =  1.2855984345073e+00;
-x3 =  2.2638953951239e+00;
-x4 =  3.2638953951239e+00;
-x5 =  4.2638953951239e+00;
-x6 =  5.2638953951239e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -61,22 +29,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 6;
+d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_8.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_8.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,46 +1,12 @@
-function [D1,H,x,h] = d1_noneq_8(N,L)
+function [D1,H] = d1_noneq_8(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<16)
     error('Operator requires at least 16 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 8;
-m = 4;
-order = 8;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  3.8118550247622e-01;
-x2 =  1.1899550868338e+00;
-x3 =  2.2476300175641e+00;
-x4 =  3.3192851303204e+00;
-x5 =  4.3192851303204e+00;
-x6 =  5.3192851303204e+00;
-x7 =  6.3192851303204e+00;
-x8 =  7.3192851303204e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -65,22 +31,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 8;
+d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_minimal_10.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_minimal_10.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,46 +1,12 @@
-function [D1,H,x,h] = d1_noneq_minimal_10(N,L)
+function [D1,H] = d1_noneq_minimal_10(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<16)
     error('Operator requires at least 16 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 8;
-m = 3;
-order = 10;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  5.8556160757529e-01;
-x2 =  1.7473267488572e+00;
-x3 =  3.0000000000000e+00;
-x4 =  4.0000000000000e+00;
-x5 =  5.0000000000000e+00;
-x6 =  6.0000000000000e+00;
-x7 =  7.0000000000000e+00;
-x8 =  8.0000000000000e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -65,22 +31,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 10;
+d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_minimal_12.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_minimal_12.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,48 +1,12 @@
-function [D1,H,x,h] = d1_noneq_minimal_12(N,L)
+function [D1,H] = d1_noneq_minimal_12(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<20)
     error('Operator requires at least 20 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 10;
-m = 4;
-order = 12;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  4.6552112904489e-01;
-x2 =  1.4647984306493e+00;
-x3 =  2.7620429464763e+00;
-x4 =  4.0000000000000e+00;
-x5 =  5.0000000000000e+00;
-x6 =  6.0000000000000e+00;
-x7 =  7.0000000000000e+00;
-x8 =  8.0000000000000e+00;
-x9 =  9.0000000000000e+00;
-x10 =  1.0000000000000e+01;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -69,22 +33,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 12;
+d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_minimal_4.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_minimal_4.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,41 +1,12 @@
-function [D1,H,x,h] = d1_noneq_minimal_4(N,L)
+function [D1,H] = d1_noneq_minimal_4(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<6)
     error('Operator requires at least 6 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 3;
-m = 1;
-order = 4;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  7.7122987842562e-01;
-x2 =  1.7712298784256e+00;
-x3 =  2.7712298784256e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -55,22 +26,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 4;
+d = [1/12,-2/3,0,2/3,-1/12];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_minimal_6.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_minimal_6.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,43 +1,12 @@
-function [D1,H,x,h] = d1_noneq_minimal_6(N,L)
+function [D1,H] = d1_noneq_minimal_6(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<10)
     error('Operator requires at least 10 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 5;
-m = 2;
-order = 6;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  4.0842950991998e-01;
-x2 =  1.1968523189207e+00;
-x3 =  2.1968523189207e+00;
-x4 =  3.1968523189207e+00;
-x5 =  4.1968523189207e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -59,22 +28,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 6;
+d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/+implementations/d1_noneq_minimal_8.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/+implementations/d1_noneq_minimal_8.m	Wed Jul 01 13:43:32 2020 +0200
@@ -1,44 +1,12 @@
-function [D1,H,x,h] = d1_noneq_minimal_8(N,L)
+function [D1,H] = d1_noneq_minimal_8(N,h)
 
-% L: Domain length
 % N: Number of grid points
-if(nargin < 2)
-    L = 1;
-end
-
 if(N<12)
     error('Operator requires at least 12 grid points');
 end
 
 % BP: Number of boundary points
-% m:  Number of nonequidistant spacings
-% order: Accuracy of interior stencil
 BP = 6;
-m = 2;
-order = 8;
-
-%%%% Non-equidistant grid points %%%%%
-x0 =  0.0000000000000e+00;
-x1 =  4.9439570885261e-01;
-x2 =  1.4051531374839e+00;
-x3 =  2.4051531374839e+00;
-x4 =  3.4051531374839e+00;
-x5 =  4.4051531374839e+00;
-x6 =  5.4051531374839e+00;
-
-xb = sparse(m+1,1);
-for i = 0:m
-    xb(i+1) = eval(['x' num2str(i)]);
-end
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Compute h %%%%%%%%%%
-h = L/(2*xb(end) + N-1-2*m);
-%%%%%%%%%%%%%%%%%%%%%%%%%
-
-%%%% Define grid %%%%%%%%
-x = h*[xb; linspace(xb(end)+1,L/h-xb(end)-1,N-2*(m+1))'; L/h-flip(xb) ];
-%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Norm matrix %%%%%%%%
 P = sparse(BP,1);
@@ -61,22 +29,9 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%
 
 %%%% Q matrix %%%%%%%%%%%
-
 % interior stencil
-switch order
-    case 2
-        d = [-1/2,0,1/2];
-    case 4
-        d = [1/12,-2/3,0,2/3,-1/12];
-    case 6
-        d = [-1/60,3/20,-3/4,0,3/4,-3/20,1/60];
-    case 8
-        d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
-    case 10
-        d = [-1/1260,5/504,-5/84,5/21,-5/6,0,5/6,-5/21,5/84,-5/504,1/1260];
-    case 12
-        d = [1/5544,-1/385,1/56,-5/63,15/56,-6/7,0,6/7,-15/56,5/63,-1/56,1/385,-1/5544];
-end
+order = 8;
+d = [1/280,-4/105,1/5,-4/5,0,4/5,-1/5,4/105,-1/280];
 d = repmat(d,N,1);
 Q = spdiags(d,-order/2:order/2,N,N);
 
--- a/+sbp/D1Nonequidistant.m	Wed Jul 01 11:15:57 2020 +0200
+++ b/+sbp/D1Nonequidistant.m	Wed Jul 01 13:43:32 2020 +0200
@@ -27,50 +27,50 @@
             switch option
 
                 case {'Accurate','accurate','A'}
-
+                    [x,h] = sbp.util.accurateBoundaryOptimizedGrid(L,m,order);
                     if order == 4
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_4(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_4(m,h);
                     elseif order == 6
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_6(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_6(m,h);
                     elseif order == 8
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_8(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_8(m,h);
                     elseif order == 10
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_10(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_10(m,h);
                     elseif order == 12
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_12(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_12(m,h);
                     else
                         error('Invalid operator order %d.',order);
                     end
 
                 case {'Minimal','minimal','M'}
-
+                    [x,h] = sbp.util.minimalBoundaryOptimizedGrid(L,m,order);
                     if order == 4
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_minimal_4(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_minimal_4(m,h);
                     elseif order == 6
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_minimal_6(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_minimal_6(m,h);
                     elseif order == 8
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_minimal_8(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_minimal_8(m,h);
                     elseif order == 10
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_minimal_10(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_minimal_10(m,h);
                     elseif order == 12
-                        [obj.D1,obj.H,obj.x,obj.h] = ...
-                            sbp.implementations.d1_noneq_minimal_12(m,L);
+                        [obj.D1,obj.H] = ...
+                            sbp.implementations.d1_noneq_minimal_12(m,h);
                     else
                         error('Invalid operator order %d.',order);
                     end
 
             end
-
-            obj.x = obj.x + x_l;
+            obj.h = h;
+            obj.x = x + x_l;
 
             obj.e_l = sparse(m,1);
             obj.e_r = sparse(m,1);