| % Computation of the Dirichlet-to-Neumann map as a matrix acting | |
| % in trigonometric basis. Omega is the unit disc. | |
| % | |
| % We actually precompute the Neumann-to-Dirichlet map using FEM, | |
| % and then find DN map by inverting the ND map and adding | |
| % appropriate mapping of constant functions. | |
| % | |
| % We compute in addition the DN map related to the constant | |
| % conductivity 1 (analytically) | |
| % and save both DN matrices to file data/ex2DN.mat. | |
| % | |
| % Routine ND_comp.m must be run before this file. | |
| % | |
| % Samuli Siltanen June 2012 | |
| % Load precomputed data | |
| load data/ND NtoD Nvec Ntrig | |
| % Invert the ND matrix to get DN matrix in trigonometric basis apart | |
| % from constant functions. | |
| DN = inv(NtoD); | |
| % Add appropriate zero row and zero column | |
| DN = [DN(:,1:Ntrig),zeros(2*Ntrig,1),DN(:,Ntrig+1:end)]; | |
| DN = [DN(1:Ntrig,:);zeros(1,2*Ntrig+1);DN(Ntrig+1:end,:)]; | |
| % Compute DN map of unit conductivity (analytically) | |
| DN1 = abs(diag([-Ntrig:Ntrig])); | |
| % Save result to file | |
| save data/ex2DN DN DN1 Ntrig | |