[petsc-users] Trouble with solving 5x5 system... Ay=x on 2 or more processors

[Gaurish Telang]

Hi,

I am trying to solve a linear system where Ay=x and A is a 5x5 matrix stored
in a binary file called 'square' and x=[1;1;1;1;1]

I am trying to display the matrix A, and the vectors x(rhs)  and y(soln) in
that order to standard output.

On running my code on a single processor the answer returned is accurate.
But on using 2 processors I get weird error messages PART of which says

[0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error Message
------------------------------------
[1]PETSC ERROR: Nonconforming object sizes!
[1]PETSC ERROR: Mat mat,Vec x: global dim 5 10!

Also somehow the vector x gets displayed TWICE when run on two processes.  A
however gets displayed ONCE (as it should!!)


I am attaching the output I get when I run on 1 process and the when I run
the same code on 2 processes.
please let me know where I could be going wrong.

(1)

This is what I get on running on ONE process:  (Here system is solved
successfully)

gaurish108 at gaurish108-laptop:~/Desktop$ $PETSC_DIR/$PETSC_ARCH/bin/mpiexec
-n 1 ./ex4 -f square

1.5761308167754828e-01 1.4188633862721534e-01 6.5574069915658684e-01
7.5774013057833345e-01 7.0604608801960878e-01
9.7059278176061570e-01 4.2176128262627499e-01 3.5711678574189554e-02
7.4313246812491618e-01 3.1832846377420676e-02
9.5716694824294557e-01 9.1573552518906709e-01 8.4912930586877711e-01
3.9222701953416816e-01 2.7692298496088996e-01
4.8537564872284122e-01 7.9220732955955442e-01 9.3399324775755055e-01
6.5547789017755664e-01 4.6171390631153941e-02
8.0028046888880011e-01 9.5949242639290300e-01 6.7873515485777347e-01
1.7118668781156177e-01 9.7131781235847536e-02
Process [0]
1
1
1
1
1
KSPGetIterationNumber 5
 KSPGetResidualNorm 0.000000
Process [0]
-0.810214
2.33178
-1.31131
1.09323
1.17322
gaurish108 at gaurish108-laptop:~/Desktop$

%--------------------------------------------------------------------
This is what I get on running on TWO processes:

(2)

gaurish108 at gaurish108-laptop:~/Desktop$ $PETSC_DIR/$PETSC_ARCH/bin/mpiexec
-n 2 ./ex4 -f square
1.5761308167754828e-01 1.4188633862721534e-01 6.5574069915658684e-01
7.5774013057833345e-01 7.0604608801960878e-01
9.7059278176061570e-01 4.2176128262627499e-01 3.5711678574189554e-02
7.4313246812491618e-01 3.1832846377420676e-02
9.5716694824294557e-01 9.1573552518906709e-01 8.4912930586877711e-01
3.9222701953416816e-01 2.7692298496088996e-01
4.8537564872284122e-01 7.9220732955955442e-01 9.3399324775755055e-01
6.5547789017755664e-01 4.6171390631153941e-02
8.0028046888880011e-01 9.5949242639290300e-01 6.7873515485777347e-01
1.7118668781156177e-01 9.7131781235847536e-02
Process [0]
1
1
1
1
1
Process [1]
1
1
1
1
1
[0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error Message
------------------------------------
[1]PETSC ERROR: Nonconforming object sizes!
[1]PETSC ERROR: Mat mat,Vec x: global dim 5 10!
[1]PETSC ERROR:
------------------------------------------------------------------------
[1]PETSC ERROR: Petsc Release Version 3.1.0, Patch 5, Mon Sep 27 11:51:54
CDT 2010
[1]PETSC ERROR: See docs/changes/index.html for recent updates.
[1]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
[1]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR: Nonconforming object sizes!
[0]PETSC ERROR: Mat mat,Vec x: global dim 5 10!
[0]PETSC ERROR: See docs/index.html for manual pages.
[1]PETSC ERROR:
------------------------------------------------------------------------
[1]PETSC ERROR: ./ex4 on a linux-gnu named gaurish108-laptop by gaurish108
Mon Jan 17 23:49:18 2011
[1]PETSC ERROR: Libraries linked from
/home/gaurish108/Desktop/ResearchMeetings/SUPERPETS/petsc-3.1-p5/linux-gnu-c-debug/lib
[1]PETSC ERROR: Configure run at Sat Nov 13 20:34:38 2010
[1]PETSC ERROR: Configure options --with-cc=gcc --with-fc=gfortran
--download-f-blas-lapack=1 --download-mpich=1 --download-superlu_dist=1
--download-parmetis=1 --with-superlu_dist=1 --with-parmetis=1
[1]PETSC ERROR:
------------------------------------------------------------------------
[1]PETSC ERROR: MatMultTranspose() line 1947 in src/mat/interface/matrix.c
[1]PETSC ERROR: KSPSolve_CGNE() line 103 in src/ksp/ksp/impls/cg/cgne/cgne.c
[1]PETSC ERROR: KSPSolve() line 396 in src/ksp/ksp/interface/itfunc.c
[1]PETSC ERROR: main() line 78 in src/mat/examples/tutorials/ex4.c
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 1[cli_1]:
aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 60) - process 1
[0]0:Return code = 0, signaled with Interrupt
[0]1:Return code = 60
gaurish108 at gaurish108-laptop:~/Desktop$
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