[petsc-dev] [petsc-users] MATNEST with shell matrices

[Amneet Bhalla]

Vijay I am running things on single processor.

Is my understanding of creation of temporary Vec vt1 right in previous
email? Also shouldn't all
temporary Vecs be generated via user-defined function for MatShell, where
one can get chance to adjust shell Vecs.

On Fri, Mar 1, 2013 at 6:31 PM, Vijay S. Mahadevan <vijay.m at gmail.com>wrote:

> Amneet, are you witnessing these errors in parallel alone, by any chance ?
>
> The reason I ask is because one of the tests using VecNest (with
> Get/Set SubVec = vec/examples/tests/ex41.c) fails in parallel and I
> have a patch to fix this (attached). The primary issue is that calls
> to SetSubVec create a mismatch in numbering of the IS maintained by
> the VecNest structure which gets propagated by VecDuplicate. This only
> happens in parallel though because the local numbering of the IS is
> what gets modified wrongly. It might be a separate unrelated issue to
> yours but cannot confirm for sure.
>
> Jed can you please review this patch. If it works, feel free to push
> after testing on ex41.c. I also have a variation of ex41 that is a
> little more rigorous but I can send that to you in a separate patch.
>
> Vijay
>
> On Fri, Mar 1, 2013 at 5:05 PM, Amneet Bhalla <mail2amneet at gmail.com>
> wrote:
> > Jed this is output from gdb:
> >
> > #0  0x0000000000000000 in ?? ()
> > #1  0x00000000009857fd in VecGetArrayRead (x=0x33ba0b0,
> a=0x7fff1f0cf100) at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/include/petsc-private/vecimpl.h:350
> > #2  0x000000000098f67f in VecGetArray_Nest (X=0x33c0850,
> x=0x7fff1f0cf200)
> > at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/vec/vec/impls/nest/vecnest.c:719
> > #3  0x0000000000a3f4df in VecGetArrayRead (x=0x33c0850,
> a=0x7fff1f0cf200) at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/include/petsc-private/vecimpl.h:350
> > #4  0x0000000000a51d83 in MatMult (mat=0x326e480, x=0x33150c0,
> y=0x33c0850)
> > at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/mat/interface/matrix.c:2092
> > #5  0x00000000012b2b78 in KSPInitialResidual (ksp=0x32f6bb0,
> > vsoln=0x33150c0, vt1=0x33c0850, vt2=0x33d3c60, vres=0x33e6d30,
> vb=0x3328710)
> > at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/interface/itres.c:54
> > #6  0x0000000000da2faa in KSPSolve_GMRES (ksp=0x32f6bb0) at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/impls/gmres/gmres.c:230
> > #7  0x0000000000d1ae6b in KSPSolve (ksp=0x32f6bb0, b=0x3328710,
> x=0x33150c0)
> > at
> >
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/interface/itfunc.c:446
> > #8  0x00000000006b8b0a in IBTK::PETScBlockKrylovLinearSolver::solveSystem
> > (this=0x31f4310, x=0x329ed20, b=0x32b75d0) at
> > PETScBlockKrylovLinearSolver.C:381
> > #9  0x00000000005777e3 in main (argc=5, argv=0x7fff1f0d3468) at
> main.C:274
> >
> > In frame 5, there is call to function
> >  PetscErrorCode  KSPInitialResidual(KSP ksp,Vec vsoln,Vec vt1,Vec vt2,Vec
> > vres,Vec vb)
> >
> > which calls the matrix-vector function in frame 4, i.e,
> > ierr = KSP_MatMult(ksp,Amat,vsoln,vt1);CHKERRQ(ierr);
> >
> > Now the error comes in frame 4, where there is call to
> > VecValidValues(y,3,PETSC_FALSE); y being vt1, a temporary left Vec to
> hold
> > value
> > of user-defined matrix vector product.
> >
> > I have passed a user-defined function to tell MatShell how to create
> > left/right Vec(s);
> > where I also set left/right->ops->getarray = PETSC_NULL. If vt1 was
> created
> > using
> > this routine, there would not have been any error related to
> > VecGetArrayRead routine
> > and should have printed some tracer printf statements. So my guess is
> that
> > this temporary
> > vector is created by directly calling VecDuplicate routine which sets
> >  vec->ops->getarray = VecGetArray_Nest by default.
> >
> >
> > On Fri, Mar 1, 2013 at 1:07 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
> >>>
> >>> Where should this routine be added and how should it look like for
> shell
> >>> vectors? I had assumed that
> >>> such changes should be done in user defined MatGetVecs routine. Clearly
> >>> this is not happening.
> >>
> >>
> >> Please explain.
> >
> >
> >
> >
> >
> > --
> > Amneet
> >
> >
> >
>



-- 
Amneet
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