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

[Jed Brown]

On Thu, Feb 28, 2013 at 12:58 PM, Amneet Bhalla <mail2amneet at gmail.com>wrote:

>
> Hi Jed,
>
> I have registered MatShell that operates on VecNest (which is composed of
> shell vectors) with KSP.
> When I am solving sytem of equations using this KSP, I am getting some
> errors. The sequence of
> events from gdb are:
>
> #0  0x0000000000000000 in ?? ()
>
> #1  0x00000000009856fd in VecGetArrayRead (x=0x3422a30, a=0x7fff8b8c6620)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/include/petsc-private/vecimpl.h:350
>
> #2  0x000000000098f57f in VecGetArray_Nest (X=0x34291d0, x=0x7fff8b8c6720)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/vec/vec/impls/nest/vecnest.c:719
>
> #3  0x0000000000a3f3df in VecGetArrayRead (x=0x34291d0, a=0x7fff8b8c6720)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/include/petsc-private/vecimpl.h:350
>

This is calling VecValidValues() checks for vec->ops->getarray. Since
VecGetArray_Nest() is implemented, it calls the routine. I'm inclined to
add a vec->ops->validvalues() and _not_ try to hack it in terms of
VecGetArray().


> #4  0x0000000000a51c83 in MatMult (mat=0x32c34f0, x=0x336a1c0, y=0x34291d0)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/mat/interface/matrix.c:2092
>
> #5  0x00000000012b2a78 in KSPInitialResidual (ksp=0x334bcb0,
> vsoln=0x336a1c0,
>     vt1=0x34291d0, vt2=0x343c150, vres=0x344f220, vb=0x337d810)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/interface/itres.c:54
>
> #6  0x0000000000da2eaa in KSPSolve_GMRES (ksp=0x334bcb0)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/impls/gmres/gmres.c:230
>
> #7  0x0000000000d1ad6b in KSPSolve (ksp=0x334bcb0, b=0x337d810,
> x=0x336a1c0)
>     at
> /home/amneet/SOFTWARES/LIBRARIESIBAMR/PETSc-3.3-Lite/src/ksp/ksp/interface/itfunc.c:446
>
> #8  0x00000000006b8a08 in IBTK::PETScBlockKrylovLinearSolver::solveSystem (
>     this=0x3249380, x=0x32f3e20, b=0x330c6d0)
>     at PETScBlockKrylovLinearSolver.C:384
>
> #9  0x00000000005777e3 in main (argc=6, argv=0x7fff8b8ca988) at main.C:274
>
> In frame 4, the user defined matrix-vector multiplication is successful (
> I printed out a statement).
> This would imply in the routine MatVecMult(Mat A, Vec x, Vec y), Vec y
> would be a duplicated
> vector. This in turn would mean that user-defined routine to duplicate
> vectors MatGetVecs(Mat A, Vec *left, Vec* right)
> should have been called. But this is not happening. It is in this routine,
> that I am setting
>
> *left->ops->getarray = PETSC_NULL;
>
> Any thoughts on what might be going on?
>
> Thanks,
> Amneet
>
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