[petsc-users] MUMPS Stuck

[Matthew Knepley]

On Thu, Dec 13, 2012 at 1:20 PM, Nachiket Gokhale <gokhalen at gmail.com> wrote:
> I am trying to solve a complex matrix equation which was assembled using
> MatCompositeMerge using MUMPS and LU preconditioner. It seems to  me that
> the solve is stuck in the factorization phase. It is taking 20 mins or so,
> using 16 processes.  A problem of the same size using reals instead of
> complex was solved previously in approximately a minute using 4 processes.
> Mumps output of -mat_mumps_icntl_4 1  at the end of this email.  Does anyone
> have any ideas about what the problem maybe ?

Complex arithmetic is much more expensive, and you can lose some of
the optimizations
made in the code. I think you have to wait longer than this. Also, you
should try attaching
the debugger to a process to see whether it is computing or waiting.

   Matt

> Thanks,
>
> -Nachiket
>
>
>
> Entering ZMUMPS driver with JOB, N, NZ =   1      122370              0
>
>  ZMUMPS 4.10.0
> L U Solver for unsymmetric matrices
> Type of parallelism: Working host
>
>  ****** ANALYSIS STEP ********
>
>  ** Max-trans not allowed because matrix is distributed
>  ... Structural symmetry (in percent)=  100
>  Density: NBdense, Average, Median   =    0   42   26
>  Ordering based on METIS
>  A root of estimated size         2736  has been selected for Scalapack.
>
> Leaving analysis phase with  ...
> INFOG(1)                                       =               0
> INFOG(2)                                       =               0
>  -- (20) Number of entries in factors (estim.) =       563723522
>  --  (3) Storage of factors  (REAL, estimated) =       565185337
>  --  (4) Storage of factors  (INT , estimated) =         3537003
>  --  (5) Maximum frontal size      (estimated) =           15239
>  --  (6) Number of nodes in the tree           =            7914
>  -- (32) Type of analysis effectively used     =               1
>  --  (7) Ordering option effectively used      =               5
> ICNTL(6) Maximum transversal option            =               0
> ICNTL(7) Pivot order option                    =               7
> Percentage of memory relaxation (effective)    =              35
> Number of level 2 nodes                        =              35
> Number of split nodes                          =               8
> RINFOG(1) Operations during elimination (estim)=   4.877D+12
> Distributed matrix entry format (ICNTL(18))    =               3
>  ** Rank of proc needing largest memory in IC facto        :         0
>  ** Estimated corresponding MBYTES for IC facto            :      3661
>  ** Estimated avg. MBYTES per work. proc at facto (IC)     :      2018
>  ** TOTAL     space in MBYTES for IC factorization         :     32289
>  ** Rank of proc needing largest memory for OOC facto      :         0
>  ** Estimated corresponding MBYTES for OOC facto           :      3462
>  ** Estimated avg. MBYTES per work. proc at facto (OOC)    :      1787
>  ** TOTAL     space in MBYTES for OOC factorization        :     28599
> Entering ZMUMPS driver with JOB, N, NZ =   2      122370        5211070
>
>  ****** FACTORIZATION STEP ********
>
>
>  GLOBAL STATISTICS PRIOR NUMERICAL FACTORIZATION ...
>  NUMBER OF WORKING PROCESSES              =          16
>  OUT-OF-CORE OPTION (ICNTL(22))           =           0
>  REAL SPACE FOR FACTORS                   =   565185337
>  INTEGER SPACE FOR FACTORS                =     3537003
>  MAXIMUM FRONTAL SIZE (ESTIMATED)         =       15239
>  NUMBER OF NODES IN THE TREE              =        7914
>  Convergence error after scaling for ONE-NORM (option 7/8)   = 0.79D+00
>  Maximum effective relaxed size of S              =   199523439
>  Average effective relaxed size of S              =    98303057
>
>  REDISTRIB: TOTAL DATA LOCAL/SENT         =      657185    14022665
>  GLOBAL TIME FOR MATRIX DISTRIBUTION       =      0.4805
>  ** Memory relaxation parameter ( ICNTL(14)  )            :        35
>  ** Rank of processor needing largest memory in facto     :         0
>  ** Space in MBYTES used by this processor for facto      :      3661
>  ** Avg. Space in MBYTES per working proc during facto    :      2018
>



--
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