[petsc-users] MATSOLVERSUPERLU_DIST not giving the correct solution

[Justin Dong]

Hi,

I'm trying to solve a linear system in parallel using SuperLU but for some
reason, it's not giving me the correct solution. I'm testing on a small
example so I can compare the sequential and parallel cases manually. I'm
absolutely sure that my routine for generating the matrix and right-hand
side in parallel is working correctly.

Running with 1 process and PCLU gives the correct solution. Running with 2
processes and using SUPERLU_DIST does not give the correct solution (I
tried with 1 process too but according to the superlu documentation, I
would need SUPERLU for sequential?). This is the code for solving the
system:

        /* solve the system */
KSPCreate(PETSC_COMM_WORLD, &ksp);
KSPSetOperators(ksp, Aglobal, Aglobal, DIFFERENT_NONZERO_PATTERN);
KSPSetType(ksp,KSPPREONLY);

KSPGetPC(ksp, &pc);

KSPSetTolerances(ksp, 1.e-13, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT);
PCFactorSetMatSolverPackage(pc, MATSOLVERSUPERLU_DIST);

KSPSolve(ksp, bglobal, bglobal);

Sincerely,
Justin
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