not enough memory?!

Zhifeng Sheng z.sheng at
Fri Nov 2 07:54:28 CDT 2007

Dear all

I have a problem for memory management.

I implemented 3d FEM code and at this moment SeqSBAIJ is used to store 
the system matrix, then I used CG method and ICC(k) preconditioner.

The test configuration is not very big, I succeeded in constructing the 
system matrix and construct the preconditioner. But when I need to setup 
the KSP solver, I got the error message below ( I also dumped some 
information about solver and system matrix):

KSP Object:
  type: cg
  maximum iterations=10000, initial guess is zero
  tolerances:  relative=1e-09, absolute=1e-50, divergence=10000
  left preconditioning
PC Object:
  type: icc
    ICC: 2 levels of fill
    ICC: factor fill ratio allocated 1
  linear system matrix = precond matrix:
  Matrix Object:
    type=seqsbaij, rows=435450, cols=435450
    total: nonzeros=9470450, allocated nonzeros=21772580
        block size is 1
[0]PETSC ERROR: --------------------- Error Message 
[0]PETSC ERROR: Out of memory. This could be due to allocating
[0]PETSC ERROR: too large an object or bleeding by not properly
[0]PETSC ERROR: destroying unneeded objects.
[0]PETSC ERROR: Memory allocated 375435120 Memory used by process 428597248
[0]PETSC ERROR: Try running with -malloc_dump or -malloc_log for info.
[0]PETSC ERROR: Memory requested 3108507040!
[0]PETSC ERROR: Petsc Release Version 2.3.2, Patch 10, Wed Mar 28 
19:13:22 CDT 2007 HG revision: d7298c71db7f5e767f359ae35d33cab3bed44428
[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: bin/main on a linux-gnu named callisto by zhifeng Fri 
Nov  2 13:26:39 2007
[0]PETSC ERROR: Libraries linked from 
[0]PETSC ERROR: Configure run at Wed Aug  8 13:46:26 2007
[0]PETSC ERROR: Configure options --with-cc=gcc --with-fc=g77 
--download-f-blas-lapack=1 --download-mpich=1 
--prefix=/u/01/01/zhifeng/install --with-shared=0
[0]PETSC ERROR: PetscMallocAlign() line 61 in src/sys/memory/mal.c
[0]PETSC ERROR: PetscTrMallocDefault() line 194 in src/sys/memory/mtr.c
[0]PETSC ERROR: PetscFreeSpaceGet() line 14 in src/mat/utils/freespace.c
[0]PETSC ERROR: MatICCFactorSymbolic_SeqSBAIJ() line 1648 in 
[0]PETSC ERROR: MatICCFactorSymbolic() line 4611 in 
[0]PETSC ERROR: PCSetup_ICC() line 117 in src/ksp/pc/impls/factor/icc/icc.c
[0]PETSC ERROR: PCSetUp() line 801 in src/ksp/pc/interface/precon.c
[0]PETSC ERROR: KSPSetUp() line 234 in src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: KSPSolve() line 338 in src/ksp/ksp/interface/itfunc.c
=====================the solver convergence info======================
Convergence in 0 iterations.
writing solution to file temp_H.vtk ...
number of unknowns >>435450
finishing the numeric solver ...
LSFIM hybrid method for four domain problem
deallocating memory of domain class ...

I debug the code, and the error is dumped by the funciton KSPSetUp() 
which should not take so much memory, but still 3108507040 memory was 
requested .... I really could not figure out where I need them...

Any help will be appreciated.

Thank you all
Best regards

More information about the petsc-users mailing list