Doing a basic cantilever bending problem to test my code which results in the linear system Au = b.
- Using DMDA for the domain and KSPSetComputeOperators - Solving it using various methods in petsc gets similar (within 1%) solutions - Even using -pc_type lu - Using KSPGetOperators and KSPGetRhs to export to matlab Exporting the matrix and and the rhs, importing them into matlab and solving with backslash gives a solution which matches the Euler-Bernoulli beam model much closer (0.4% error vs 9.6%). Calculating the residual of petsc's solution using matlab ( norm(A*u-b)/norm(b)) I get 0.3 having solved with -pc_type lu. Is there a way I could have accidentally made petsc solve a different problem to Ax=b? I've been looking at this code for a while now (days) and can't seem to figure out what is wrong.
