[petsc-users] Diagnosing Poisson Solver Behavior

[K. N. Ramachandran]

Hello Barry,

The full error message is

[0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[0]PETSC ERROR: Argument out of range
[0]PETSC ERROR: Inserting a new nonzero at (25,27) in the matrix
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.6.2, Oct, 02, 2015
[0]PETSC ERROR: /gpfs/work/(user name)/progs/PICC_Code/piccode on a
linux-debug named (host) by (user) Thu Oct 15 11:22:41 2015
[0]PETSC ERROR: Configure options --with-fc=mpif90 PETSC_ARCH=linux-debug
--with-debugging=1 --with-clanguage=cxx --with-cxx=mpicxx --with-cc=mpicc
--with-blas-lib="-L/usr/global/intel/mkl/11.0.0.079/lib/intel64 -lmkl_rt"
--with-lapack-lib="-L/usr/global/intel/mkl/11.0.0.079/lib/intel64 -lmkl_rt"
--with-shared-libraries --with-x=0 --download-hypre=1
[0]PETSC ERROR: #1 MatSetValues_SeqAIJ() line 484 in /gpfs/scratch/(user
name)/petsc-3.6.2/src/mat/impls/aij/seq/aij.c
[0]PETSC ERROR: #2 MatSetValues() line 1173 in /gpfs/scratch/(user
name)/petsc-3.6.2/src/mat/interface/matrix.c
[0]PETSC ERROR: #3 MatCopy_Basic() line 3722 in /gpfs/scratch/(user
name)/petsc-3.6.2/src/mat/interface/matrix.c
[0]PETSC ERROR: #4 MatCopy_SeqAIJ() line 2630 in /gpfs/scratch/(user
name)/petsc-3.6.2/src/mat/impls/aij/seq/aij.c
[0]PETSC ERROR: #5 MatCopy() line 3779 in /gpfs/scratch/(user
name)/petsc-3.6.2/src/mat/interface/matrix.c
48        MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);
(gdb) n
49        MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);


I tried a DMDACreate1D where I specify the dimension as n^3, where n is the
number of nodes on one side of the cube, but I still get the same error.
The error is generated at the MatCopy line as mentioned earlier.

In parallel you will not be able to reuse some old code to "compute the
> Finite difference discretization of a 3D regular grid" so you might
> consider just discarding that old code and using what PETSc provides for
> computing the "Finite difference discretization of a 3D regular grid."
>

Ah ok, I had meant to say Finite difference discretization of the Poisson
equation.

If my parallel code could generate the sparse matrices formats for the
portion owned by each ranks, would there be a convenient way to generate
the PETSc matrices to be part of the DM? I had noticed that
CreateMatSeqAIJWithArrays changes the location of the Mat pointer passed in
for ComputeMatrix, so the actual matrix in DM remains as all zeros, so my
final solution comes out as zeros too.


Thanking You,
K.N.Ramachandran
Ph: 814-441-4279
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