UMFPACK out of memory

[francois pacull]

Thank you Matt for your quick reply.

I will try to use MUMPS soon. About UMFPACK, the OS used is a 64-bit 
Linux one. Also, we do have 64-bit pointers from what I understand; the 
following lines are from the PETSc configure.log file:

#ifndef PETSC_SIZEOF_VOID_P
#define PETSC_SIZEOF_VOID_P 8
#endif

And here is the umfpack_UMF_report_info from the subdomain that crashed:


UMFPACK V5.4.0 (May 20, 2009), Info:
    matrix entry defined as:          double
    Int (generic integer) defined as: int
    BLAS library used: Fortran BLAS.  size of BLAS integer: 4
    MATLAB:                           no.
    CPU timer:                        POSIX times ( ) routine.
    number of rows in matrix A:       79002
    number of columns in matrix A:    79002
    entries in matrix A:              12030970
    memory usage reported in:         8-byte Units
    size of int:                      4 bytes
    size of UF_long:                  8 bytes
    size of pointer:                  8 bytes
    size of numerical entry:          8 bytes

    strategy used:                    unsymmetric
    ordering used:                    colamd on A
    modify Q during factorization:    yes
    prefer diagonal pivoting:         no
    pivots with zero Markowitz cost:               0
    submatrix S after removing zero-cost pivots:
        number of "dense" rows:                    0
        number of "dense" columns:                 0
        number of empty rows:                      0
        number of empty columns                    0
        submatrix S square and diagonal preserved
    symbolic factorization defragmentations:       0
    symbolic memory usage (Units):                 27435792
    symbolic memory usage (MBytes):                209.3
    Symbolic size (Units):                         177636
    Symbolic size (MBytes):                        1
    symbolic factorization CPU time (sec):         4.95
    symbolic factorization wallclock time(sec):    4.95

    symbolic/numeric factorization:      upper bound               
actual      %
    variable-sized part of Numeric object:
        initial size (Units)                31236744                    
-      -
        peak size (Units)                  597607658                    
-      -
        final size (Units)                 550474688                    
-      -
    Numeric final size (Units)             550988250                    
-      -
    Numeric final size (MBytes)               4203.7                    
-      -
    peak memory usage (Units)              598718594                    
-      -
    peak memory usage (MBytes)                4567.9                    
-      -
    numeric factorization flops          1.63141e+12                    
-      -
    nz in L (incl diagonal)                171352664                    
-      -
    nz in U (incl diagonal)                346187947                    
-      -
    nz in L+U (incl diagonal)              517461609                    
-      -
    largest front (# entries)               15783705                    
-      -
    largest # rows in front                     2815                    
-      -
    largest # columns in front                  5607                    
-      -


UMFPACK V5.4.0 (May 20, 2009): ERROR: out of memory

Thanks again,
francois.



Matthew Knepley a écrit :
> On Tue, Oct 27, 2009 at 10:12 AM, francois pacull <fpacull at fluorem.com 
> <mailto:fpacull at fluorem.com>> wrote:
>
>     Dear PETSc team,
>
>     I have a few questions... During the resolution of a linear system
>     in parallel, I am trying to apply a local LU solver to each of the
>     SEQaij diagonal blocks of a MPIaij matrix partitioned with PARMETIS.
>
>     - I started with MUMPS but it seems that it only works with
>     unpartitioned aij matrices, is it really the case? Or could we use
>     MUMPS to build an additive Schwarz preconditioner for example?
>
>
> You can use MUMPS for the subproblem solver.
>  
>
>     - Then I tried UMFPACK. This works fine when the diagonal blocks
>     (and the memory required to store the factors) are small but
>     crashes when they are a little bit larger. For example with a
>     "numeric final size" of 4203.7 MBytes,  I got the following
>     message "ERROR: out of memory" while there was plenty of memory
>     left in the computer. I tried either with the UMFPACK version 5.2,
>     downloaded by PETSc, or with a manually installed version 5.4,
>     linked to PETSc. Is this a behavior from UMFPACK that you already
>     experienced?
>
>
> Send all the error output. However, in oder to address more than 4G, 
> you will need 64-bit pointers.
>
>     - Since UMFPACK seemed to have a memory limit around 4096 MB,  I
>     tried to install a PETSc version with the option
>     "--with-64-bit-indices", however none of the partitioning packages
>     could be compiled with this option
>     (parmetis,chaco,jostle,party,scotch). Is there a way to compile
>     PETSc with 64 bit indices AND a partitioning package?
>
>
> Not that I know of.
>  
>
>     - Finally, I tried to modify the PETSc source code umfpack.c so
>     that it would deal with 64 bit indices, but I only ended up so far
>     with a segmentation violation message at the execution... Is it
>     the only way I could use UMPACK with large sparse matrices?
>
>
> Why not just upgrade to a 64-bit OS if you want to address so much 
> memory on a single machine?
>
>   Matt
>  
>
>     Thank you,
>     Regards,
>     francois pacull.
>
>
>
>
> -- 
> 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