[petsc-users] Ask for help in tracking down bugs - setting #threads for pardiso block LU solver

[Voinov, Boris]

Hello,

Could you please help me to figure out what's wrong with the way I'm trying to make mkl pardiso use the number of threads more than one while setting it as a sub PC solver for ASM preconditioner.
Here is how I do this
Loop over block PCs {
  PCSetType(subPc, PCLU);             set subPC type
  PCFactorSetMatSolverType(subPc, MATSOLVERMKL_PARDISO);       set solver for LU
  SetPardisoParams("pardiso");      set mkl related options including -mat_mkl_pardiso_65 equal to the desired #threads; return code after PetscOptionsSetValue is ok, so I presume the option is set correctly.
  PCSetFromOptions(subPc);
}

Then what I see under the debugger
PCSetUp after a series of calls gets to MatLUFactorSymbolic_AIJMKL_PARDISO which in turn calls MatSetFromOptions_MKL_PARDISO(F, A) and there
in these lines it seems to ignore what I've set for -mat_mkl_pardiso_65 and sets #threads to the default 1
PetscCall(PetscOptionsInt("-mat_mkl_pardiso_65", "Suggested number of threads to use within PARDISO", "None", threads, &threads, &flg));
if (flg) PetscSetMKL_PARDISOThreads((int)threads);

This is about petsc-3.20.
PS when I do this in a standalone code which reads a matrix and solves the linear system and set -mat_mkl_pardiso_65 in the command line it's all right but I need the number of threads to be set in other way in my code.

Thank you and best regards,
Boris

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