PetscMalloc petsc-3.0.0-p4

[Matthew Knepley]

More specifically, you have overflowed exactly to 0, thus PetscMalloc()
returns without
an error code, as it says in the docs.

  Matt

On Mon, Mar 23, 2009 at 7:47 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

> [anlextwls097-161:~/Documents/RandD-100] barrysmith% python
>
> >>> npixel = 256*256*5
> >>> print npixel
> 327,680
> >>> print npixel*npixel
> 107,374,182,400
>
>
> The problem is that your n is too big to fit into a PetscInt hence bad
> stuff happens.
> This is a fatal flaw of C, it doesn't generation exceptions for integer
> overflow.
>
> If you want to have sizes this big you need to config/configure.py PETSc
> with
> --with-64-bit-indices then PETSc uses 64 bit integers for PETSc and things
> will fit.
> Of course, likely you still won't have enough memory to allocate such a big
> dense matrix.
>
>  Barry
>
>
>
> On Mar 23, 2009, at 6:41 PM, David Fuentes wrote:
>
>
>>
>> running on ubuntu 8.04.
>>
>> the following code should reproduce the problem.
>>
>>
>>
>> static char help[] = "MatCreateSeqDense\n\n";
>>
>> #include "petscpc.h"
>>
>> #undef __FUNCT__
>> #define __FUNCT__ "main"
>> int main(int argc,char **args)
>> {
>>  Mat            mat;
>>  PetscErrorCode ierr;
>>  PetscInt       npixel = 256*256*5;
>>  PetscInt       n= npixel * npixel;
>>
>>  PetscInitialize(&argc,&args,(char *)0,help);
>>
>>
>>  /* Create and assemble matrix */
>>  ierr =
>> MatCreateSeqDense(PETSC_COMM_SELF,n,n,PETSC_NULL,&mat);CHKERRQ(ierr);
>>  ierr = MatSetValue(mat,1,1,1.0,INSERT_VALUES);CHKERRQ(ierr);
>>  ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
>>  ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
>>
>>  /* Free data structures */
>>  ierr = MatDestroy(mat);CHKERRQ(ierr);
>>  ierr = PetscFinalize();CHKERRQ(ierr);
>>  return 0;
>> }
>>
>>
>>
>> below is my error message.
>>
>>
>>
>>
>>
>> [0]PETSC ERROR: --------------------- Error Message
>> ------------------------------------
>> [0]PETSC ERROR: Argument out of range!
>> [0]PETSC ERROR: Row too large: row 1 max -1!
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR: Petsc Release Version 3.0.0, Patch 4, Fri Mar  6
>> 14:46:08 CST 2009
>> [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: ./ex4 on a intel-10. named setebos.ices.utexas.edu by
>> fuentes Mon Mar 23 18:39:32 2009
>> [0]PETSC ERROR: Libraries linked from
>>
>> /org/groups/oden/LIBRARIES/PETSC/petsc-3.0.0-p4/intel-10.1-mpich2-1.0.7-cxx-dbg/lib
>> [0]PETSC ERROR: Configure run at Fri Mar 20 20:39:04 2009
>> [0]PETSC ERROR: Configure options
>> --with-mpi-dir=/org/groups/oden/LIBRARIES/MPI/mpich2-1.0.7-intel-10.1
>> --with-clanguage=C++ --with-shared=1
>> --with-blas-lapack-dir=/opt/intel/mkl/10.0.3.020 --download-mumps=1
>> --download-parmetis=1 --download-scalapack=1 --download-blacs=1
>> --download-plapack=1 --download-superlu_dist=1
>> [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> [0]PETSC ERROR: MatSetValues_SeqDense() line 672 in
>> src/mat/impls/dense/seq/dense.c
>> [0]PETSC ERROR: MatSetValues() line 921 in src/mat/interface/matrix.c
>> [0]PETSC ERROR: main() line 21 in src/ksp/pc/examples/tests/ex4.c
>> application called MPI_Abort(MPI_COMM_WORLD, 63) - process 0[unset]:
>> aborting job:
>> application called MPI_Abort(MPI_COMM_WORLD, 63) - process 0
>>
>>
>>
>>
>>
>>
>> df
>>
>>
>>
>>
>> On Mon, 23 Mar 2009, Lisandro Dalcin wrote:
>>
>>  1) Which system are you running on?
>>>
>>> 2) are you completely sure BOTH things happens, I mean... that malloc
>>> returns null AND the error code is zero?
>>>
>>>
>>> On Mon, Mar 23, 2009 at 7:49 PM, David Fuentes <fuentesdt at gmail.com>
>>> wrote:
>>>
>>>> In 3.0.0-p4
>>>>
>>>> PetscMalloc doesn't seem to return an error code if the requested memory
>>>> wasn't allocated ? Is this correct ?
>>>>
>>>> I'm trying to allocate a dense matrix for which there was not enough
>>>> memory
>>>> and PetscMalloc is returning a null pointer but no errorcode to
>>>> catch. which is causing seg faults later.
>>>>
>>>>
>>>>
>>>> thanks,
>>>> df
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Lisandro Dalcín
>>> ---------------
>>> Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
>>> Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
>>> Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
>>> PTLC - Güemes 3450, (3000) Santa Fe, Argentina
>>> Tel/Fax: +54-(0)342-451.1594
>>>
>>>
>


-- 
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
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