[petsc-users] Nonconforming object sizes with KSPSolve

[Mengda Wu]

Hi all,

   I am trying to use KSPLSQR to solve an overdetermined system. I am NOT
using MPI. I got an error "Nonconforming object sizes!" in KSPSolve. It is
very weird because this happens after the iterations are converged. Please
see the following messages.

==================================================================
159 KSP Residual norm 1.808481783605e-004
Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 159
[0]PETSC ERROR: --------------------- Error Message
----------------------------
--------
[0]PETSC ERROR: Nonconforming object sizes!
[0]PETSC ERROR: Mat mat,Vec y: global dim 4012 1452!
[0]PETSC ERROR:
----------------------------------------------------------------
--------
[0]PETSC ERROR: Petsc Release Version 3.3.0, Patch 6, Mon Feb 11 12:26:34
CST 20
13
[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: MCMeshSeg on a arch-mswi named pcs by wmd00 Fri Mar
08 18:50:53 2013
[0]PETSC ERROR: Libraries linked from
/cygdrive/d/Library/PETSc/petsc-3.3-p6/arc
h-mswin-c-opt/lib
[0]PETSC ERROR: Configure run at Thu Feb 14 19:42:41 2013
[0]PETSC ERROR: Configure options --with-cc=cl --with-fc=0 --with-cxx=cl
--with-
mpi=0 --with-debugging=0
--download-f2cblaslapack=/cygdrive/d/Library/PETSc/down
load/f2cblaslapack-3.4.1.q.tar.gz --with-sowing=0 --with-c2html=0
-CFLAGS="-MD -
wd4996" -CXXFLAGS="-MD -wd4996" --useThreads=0
[0]PETSC ERROR:
----------------------------------------------------------------
--------
[0]PETSC ERROR: MatMult() line 2082 in
src/mat/interface/D:\Library\PETSc\PETSC-
~2.3-P\src\mat\INTERF~1\matrix.c
[0]PETSC ERROR: KSPSolve() line 632 in
src/ksp/ksp/interface/D:\Library\PETSc\PE
TSC-~2.3-P\src\ksp\ksp\INTERF~1\itfunc.c
[0]PETSC ERROR: User provided function() line 1200 in
"unknowndirectory/"..\..\g
uiMeshSeg\MCMeshSeg.cpp

==================================================================

I created the matrix and vector with the following code:
int MatrixCreate(size_t row, size_t col, Vec& vecsol, Vec& vecrhs, Mat&
matA, KSP& ksp)
{
    if( !isMeshLoaded ) return 1;

    if( !isSolverInitialized ) SolverInitialize();

    PetscErrorCode ierr;

    ierr = VecCreateSeq(PETSC_COMM_SELF,col,&vecsol);CHKERRQ(ierr);
    ierr = VecCreateSeq(PETSC_COMM_SELF,row,&vecrhs);CHKERRQ(ierr);
    ierr =
MatCreateSeqAIJ(PETSC_COMM_SELF,row,col,10,PETSC_NULL,&matA);CHKERRQ(ierr);

    ierr = KSPCreate(PETSC_COMM_SELF,&ksp);CHKERRQ(ierr);

        ierr = KSPSetType(ksp,KSPLSQR);CHKERRQ(ierr);
        PC pc;
        ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
        ierr = PCSetType(pc,PCNONE);CHKERRQ(ierr);
        ierr =
KSPSetTolerances(ksp,1.0e-6,PETSC_DEFAULT,PETSC_DEFAULT,5000);CHKERRQ(ierr);

    ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);

    return 0;
}

And I solved the system using:
        ierr = KSPSetInitialGuessNonzero(ksp, PETSC_FALSE);CHKERRQ(ierr);
        ierr =
KSPSetOperators(ksp,matA,matA,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
        ierr = KSPSolve(ksp,vecrhs,vecsol);CHKERRQ(ierr);
        ierr = VecGetArray(vecsol,&avecsol);CHKERRQ(ierr);

Where is the problem?

Thanks,
Mengda
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