Performance degradation after upgrade to 3.0.0

[Billy Araújo]

Hi,

I have also verified that there has been a degradation of performance using the new 3.0 version:

This is my function calling PETSc:

  KSP ksp;
  PC pc;

  KSPCreate (PETSC_COMM_WORLD, &ksp);

  KSPSetOperators (ksp, *A, *A, DIFFERENT_NONZERO_PATTERN);

  KSPSetType (ksp, KSPFGMRES);

  KSPGetPC (ksp, &pc);

  PCSetType (pc, PrecondProc);

  KSPSetInitialGuessNonzero (ksp, PETSC_TRUE);

  KSPSetTolerances (ksp, 1E-50, maxtol, PETSC_DEFAULT, maxiter);

  KSPSetFromOptions (ksp);

  KSPSolve (ksp, *b, *x);

  KSPGetIterationNumber (ksp, iter);

  KSPGetResidualNorm (ksp, res);

  KSPDestroy (ksp);


with previous version 2.3.3-p6:

Number of iterations: 42 Residual: +7.073781E-13 Time: +8.615024E-03

now:

Number of iterations: 500 Residual: +2.746161E-05 Time: +1.026870E-01

It is reaching maximum number of iterations. The only thing I changed was:

MatSetOption (*A, MAT_SYMMETRIC);
 to 
MatSetOption (*A, MAT_SYMMETRIC, PETSC_TRUE);

I think I didn't change anything else.


Regards,

Billy.
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