[petsc-users] problem with MatShellGetContext

[Nicolas Pozin]

Thank you! 

----- Mail original -----

> De: "Matthew Knepley" <knepley at gmail.com>
> À: "Nicolas Pozin" <nicolas.pozin at inria.fr>
> Cc: "PETSc" <petsc-users at mcs.anl.gov>
> Envoyé: Mercredi 5 Août 2015 13:38:20
> Objet: Re: [petsc-users] problem with MatShellGetContext

> On Wed, Aug 5, 2015 at 4:15 AM, Nicolas Pozin < nicolas.pozin at inria.fr >
> wrote:

> > Hello,
> 

> > I'm trying to solve a system with a matrix free operator and through
> > conjugate gradient method.
> 
> > To make ideas clear, I set up the following simple example (I am using
> > petsc-3.6) and I get this error message :
> 

> Yes, you are passing a C++ function userMult, so the compiler sticks "this"
> in as the first argument. We do not
> recommend this kind of wrapping.

> Thanks,

> Matt

> > "
> 
> > [0]PETSC ERROR: --------------------- Error Message
> > ------------------------------------
> 
> > [0]PETSC ERROR: Invalid argument!
> 
> > [0]PETSC ERROR: Wrong type of object: Parameter # 1!
> 
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> 
> > [0]PETSC ERROR: Petsc Release Version 3.4.3, Oct, 15, 2013
> 
> > [0]PETSC ERROR: See docs/changes/index.html for recent updates.
> 
> > [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
> 
> > [0]PETSC ERROR: See docs/index.html for manual pages.
> 
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> 
> > [0]PETSC ERROR: ./test on a ubuntu_release named pl-59080 by npozin Wed Aug
> > 5
> > 10:55:26 2015
> 
> > [0]PETSC ERROR: Libraries linked from
> > /home/npozin/Felisce_libraries/petsc_3.4.3/ubuntu_release/lib
> 
> > [0]PETSC ERROR: Configure run at Wed Jul 22 16:18:36 2015
> 
> > [0]PETSC ERROR: Configure options PETSC_ARCH=ubuntu_release --with-cxx=g++
> > --with-fc=gfortran --with-cc=gcc --with-x=0 --download-openmpi
> > --download-f-blas-lapack --download-superlu --download-superlu_dist
> > --with-superlu_dist=1 --download-metis --download-mumps --download-parmetis
> > --with-superlu_dist=1 --download-boost --with-boost=1 --download-scalapack
> > with-external-packages-dir=/home/npozin/Felisce_libraries/petsc_3.4.3/packages
> 
> > [0]PETSC ERROR:
> > ------------------------------------------------------------------------
> 
> > [0]PETSC ERROR: MatShellGetContext() line 202 in
> > /home/npozin/Felisce_libraries/petsc_3.4.3/src/mat/impls/shell/shell.c
> 
> > End userMult
> 
> > [0]PETSC ERROR: MatMult() line 2179 in
> > /home/npozin/Felisce_libraries/petsc_3.4.3/src/mat/interface/matrix.c
> 
> > [0]PETSC ERROR: KSP_MatMult() line 204 in
> > /home/npozin/Felisce_libraries/petsc_3.4.3/include/petsc-private/kspimpl.h
> 
> > [0]PETSC ERROR: KSPSolve_CG() line 219 in
> > /home/npozin/Felisce_libraries/petsc_3.4.3/src/ksp/ksp/impls/cg/cg.c
> 
> > [0]PETSC ERROR: KSPSolve() line 441 in
> > /home/npozin/Felisce_libraries/petsc_3.4.3/src/ksp/ksp/interface/itfunc.c
> 
> > "
> 

> > I don't understand where the problem comes from with the matrix argument of
> > MatShellGetContext.
> 
> > Any idea on what I do wrong?
> 

> > Thanks a lot,
> 
> > Nicolas
> 

> > #include <iostream>
> 
> > #include <petscksp.h>
> 

> > using namespace std;
> 

> > typedef struct {
> 
> > int val;
> 
> > } MyCtx;
> 

> > class ShellClass {
> 
> > Mat matShell;
> 
> > KSP ksp;
> 
> > PC pc;
> 
> > Vec x;
> 
> > Vec b;
> 

> > public:
> 
> > void userMult(Mat Amat, Vec x, Vec y) {
> 
> > cout << "Inside userMult" << endl;
> 

> > MyCtx *ctx;
> 
> > MatShellGetContext(Amat, (void *) ctx);
> 

> > cout << "End userMult" << endl;
> 
> > }
> 

> > void solveShell() {
> 
> > // context
> 
> > MyCtx *ctx = new MyCtx;
> 
> > ctx->val = 42;
> 

> > // pc
> 
> > PCCreate(PETSC_COMM_WORLD, &pc);
> 
> > PCSetType(pc, PCNONE);
> 

> > // ksp
> 
> > KSPCreate(PETSC_COMM_WORLD, &ksp);
> 
> > KSPSetType(ksp, KSPCG);
> 
> > KSPSetPC(ksp, pc);
> 
> > KSPSetFromOptions(ksp);
> 

> > // matshell
> 
> > int m = 10;
> 
> > int n = 10;
> 
> > MatCreateShell(PETSC_COMM_WORLD, m, n, PETSC_DETERMINE, PETSC_DETERMINE,
> > ctx,
> > &matShell);
> 
> > MatShellSetOperation(matShell, MATOP_MULT,
> > (void(*)(void))&ShellClass::userMult);
> 

> > // create vectors
> 
> > MatCreateVecs(matShell, &x, 0);
> 
> > VecDuplicate(x, &b);
> 
> > VecSet(b, 1.);
> 

> > // set operators
> 
> > KSPSetOperators(ksp, matShell, matShell);
> 

> > // solve (call to userMult)
> 
> > KSPSolve(ksp, b, x);
> 
> > }
> 
> > };
> 

> > int main(int argc, char** argv) {
> 
> > PetscInitialize(&argc, &argv, NULL, NULL);
> 

> > ShellClass foo;
> 
> > foo.solveShell();
> 

> > PetscFinalize();
> 
> > return 0;
> 
> > }
> 

> --
> What most experimenters take for granted before they begin their experiments
> is infinitely more interesting than any results to which their experiments
> lead.
> -- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150805/5edd0b7b/attachment.html>