[petsc-users] PCSHELL does not support getting factor matrix

[Stefano Zampini]

Oh, I see the stack trace now. This requires to compute the inertia?

> On Nov 19, 2021, at 3:45 PM, Stefano Zampini <stefano.zampini at gmail.com> wrote:
> 
> Jose
> 
> Now that we have the PCMatApply interface, you could  switch to use that inside SLEPc. I guess you are using MatSolve, right?
> If not, the alternative is to have a PCFactorGetMatrix with creates on the fly an object that behaves like it. The problem is that we do not have a matching restore, and the new object created will be leaked.
> What do you think?
> 
> 
>> On Nov 19, 2021, at 12:41 PM, Jose E. Roman <jroman at dsic.upv.es> wrote:
>> 
>> It is trying to call PCFactorGetMatrix() on your PC, but this operation is not supported by PCSHELL and it is not possible to set it via PetscObjectComposeFunction(). PCSHELL uses the PCShellSet* interface, that is restricted to a limited number of operations.
>> 
>> Jose
>> 
>> 
>>> El 19 nov 2021, a las 6:30, Sam Guo <sam.guo at cd-adapco.com> escribió:
>>> 
>>> Dear PETSc dev team,
>>>  I am implementing SLEPc interval option using shell matrix as follows:
>>> 
>>> EPSGetST(eps, &st);
>>> STSetType(st, STSINVERT);
>>> STGetKSP(st, &ksp);
>>> KSPSetOperators(ksp, A, A);
>>> KSPSetType(ksp, KSPPREONLY);
>>> KSPGetPC(ksp, &pc);
>>> KSPGetPC(ksp, &pc)
>>> MatSetOption(A, MAT_SPD, PETSC_TRUE);
>>> PCSetType(pc, PCSHELL);
>>> PCShellSetContext(pc, &appCtx);
>>> PCShellSetApply(pc, applyPreconditioner);
>>> PetscObjectComposeFunction((PetscObject)pc,"PCFactorGetZeroPivot_C",PCFactorGetZeroPivot_C);
>>> 
>>> When I run it, I get the following error.  Any idea what I did wrong? Thanks a lot for your help.
>>> 
>>> [0]PETSC ERROR: No support for this operation for this object type
>>> [0]PETSC ERROR: PC type does not support getting factor matrix
>>> [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
>>> [0]PETSC ERROR: Petsc Release Version 3.11.3, Jun, 26, 2019 
>>> [0]PETSC ERROR: Unknown Name on a arch-starccmplus_serial_real named pl2usbvu0037pc.net.plm.eds.com by cd4hhv Thu Nov 18 21:11:45 2021
>>> Number of iterations of the method: 0
>>> [0]PETSC ERROR: Configure options --with-x=0 --with-fc=0 --with-debugging=1 --with-blaslapack-dir=/u/cd4hhv/dev2/mkl/2017.2-cda-001/linux/lib/intel64/../.. --with-mpi=0 -CFLAGS=-g -CXXFLAGS=-g --with-clean=1 --force --with-scalar-type=real
>>> [0]PETSC ERROR: #1 PCFactorGetMatrix() line 1332 in ../../../petsc/src/ksp/pc/interface/precon.c
>>> [0]PETSC ERROR: #2 EPSSliceGetInertia() line 340 in ../../../slepc/src/eps/impls/krylov/krylovschur/ks-slice.c
>>> [0]PETSC ERROR: #3 EPSSetUp_KrylovSchur_Slice() line 467 in ../../../slepc/src/eps/impls/krylov/krylovschur/ks-slice.c
>>> [0]PETSC ERROR: #4 EPSSetUp_KrylovSchur() line 146 in ../../../slepc/src/eps/impls/krylov/krylovschur/krylovschur.c
>>> [0]PETSC ERROR: #5 EPSSetUp() line 173 in ../../../slepc/src/eps/interface/epssetup.c
>>> Solution method: krylovschur
>>> [0]PETSC ERROR: #6 EPSSliceGetEPS() line 306 in ../../../slepc/src/eps/impls/krylov/krylovschur/ks-slice.c
>>> [0]PETSC ERROR: #7 EPSSetUp_KrylovSchur_Slice() line 416 in ../../../slepc/src/eps/impls/krylov/krylovschur/ks-slice.c
>>> [0]PETSC ERROR: #8 EPSSetUp_KrylovSchur() line 146 in ../../../slepc/src/eps/impls/krylov/krylovschur/krylovschur.c
>>> [0]PETSC ERROR: #9 EPSSetUp() line 173 in ../../../slepc/src/eps/interface/epssetup.c
>> 
>