[petsc-users] MUMPS icntl for petsc4py

[Quentin Chevalier]

Many thanks Jose, it works beautifully !

I'm at a loss as to why, but thanks for the quick fix !

Quentin



Quentin CHEVALIER – IA parcours recherche

LadHyX - Ecole polytechnique

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On Sun, 22 Jan 2023 at 10:58, Jose E. Roman <jroman at dsic.upv.es> wrote:
>
> You have to call ST.getOperator() as is done in this C example:
> https://slepc.upv.es/documentation/current/src/eps/tutorials/ex43.c.html
>
> Jose
>
>
> > El 22 ene 2023, a las 10:40, Quentin Chevalier <quentin.chevalier at polytechnique.edu> escribió:
> >
> > Hello PETSc users,
> >
> > I'm getting an INFOG(1)=-9 and INFO(2)=27 error on an eigenvalue code based on dolfinx run in a docker container. Based on https://mumps-solver.org/doc/userguide_5.5.1.pdf, I figured the fix would be to increase ICNTL(14).
> >
> > I'm coding in python through the petsc4py/slepc4py wrapper. I found a Mat.setMumpsIcntl method but I can't seem to place it properly and always obtain another error : "Operation done in wrong order and the like".
> >
> > Here's the code snippet that is failing :
> > # Solver
> > EPS = SLEPc.EPS().create(COMM_WORLD)
> > EPS.setOperators(-A,M) # Solve Ax=sigma*Mx
> > EPS.setProblemType(SLEPc.EPS.ProblemType.PGNHEP) # Specify that A is not hermitian, but M is semi-definite
> > EPS.setWhichEigenpairs(EPS.Which.TARGET_MAGNITUDE) # Find eigenvalues close to sigma
> > EPS.setTarget(sigma)
> > EPS.setDimensions(2,10) # Find k eigenvalues only with max number of Lanczos vectors
> > EPS.setTolerances(1e-9,100) # Set absolute tolerance and number of iterations
> > # Spectral transform
> > ST = EPS.getST(); ST.setType('sinvert')
> > # Krylov subspace
> > KSP = ST.getKSP()
> > KSP.setTolerances(rtol=1e-6, atol=1e-9, max_it=100)
> > # Krylov subspace
> > KSP.setType('preonly')
> > # Preconditioner
> > PC = KSP.getPC(); PC.setType('lu')
> > PC.setFactorSolverType('mumps')
> > KSP.setFromOptions()
> > EPS.setFromOptions()
> > PC.getFactorMatrix().setMumpsIcntl(14,50)
> > print(f"Solver launch for sig={sigma:.1f}...",flush=True)
> > EPS.solve()
> > n=EPS.getConverged()
> >
> > For context, matrix A is complex, size 500k x 500k but AIJ sparse, and I'm running this code on 36 nodes.
> >
> > I'd appreciate any insight on how to fix this issue, it's not clear to me what the order of operations should be. Funnily enough, it's very shift-dependent.
> >
> > Cheers,
> >
> > Quentin
>