Mercurial > repos > public > sbplib
diff +sbp/+util/minimalBoundaryOptimizedGrid.m @ 1285:6b68f939d023 feature/boundary_optimized_grids
Add utility functions for constructing the grids used by the boundary optimized D1Nonequidistant opsets
author | Vidar Stiernström <vidar.stiernstrom@it.uu.se> |
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date | Wed, 01 Jul 2020 11:15:57 +0200 |
parents | |
children | 38653d26225c |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/+sbp/+util/minimalBoundaryOptimizedGrid.m Wed Jul 01 11:15:57 2020 +0200 @@ -0,0 +1,49 @@ +function [x,h] = minimalBoundaryOptimizedGrid(L,N,order) + %%%% Non-equidistant grid points %%%%% + xb = boundaryPoints(order); + m = length(xb)-1; % Number of non-equidistant points + assert(N-2*(m+1)>=0,'Not enough grid points to contain the boundary region. Requires at least %d points.',2*(m+1)); + %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + %%%% 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) ]; + %%%%%%%%%%%%%%%%%%%%%%%%% +end + +function xb = boundaryPoints(order) + switch order + case 4 + x0 = 0.0000000000000e+00; + x1 = 7.7122987842562e-01; + xb = [x0 x1]'; + case 6 + x0 = 0.0000000000000e+00; + x1 = 4.0842950991998e-01; + x2 = 1.1968523189207e+00; + xb = [x0 x1 x2]'; + case 8 + x0 = 0.0000000000000e+00; + x1 = 4.9439570885261e-01; + x2 = 1.4051531374839e+00; + xb = [x0 x1 x2]'; + case 10 + x0 = 0.0000000000000e+00; + x1 = 5.8556160757529e-01; + x2 = 1.7473267488572e+00; + x3 = 3.0000000000000e+00; + xb = [x0 x1 x2 x3]'; + case 12 + x0 = 0.0000000000000e+00; + x1 = 4.6552112904489e-01; + x2 = 1.4647984306493e+00; + x3 = 2.7620429464763e+00; + x4 = 4.0000000000000e+00; + xb = [x0 x1 x2 x3 x4]'; + otherwise + error('Invalid operator order %d.',order); + end +end \ No newline at end of file