Re: not enough memory?!

[Zhifeng Sheng <z.sheng@xxxxxxxxxxxxxx>]

Hong Zhang wrote:

> k>>>
>
> > > >
> > So ... computation of the preconditioner is actually called by 
> > KSPSetUp() instead of PCGetFactoredMatrix(prec,&M)?
>
>
> Yes.
>
> > Could you please tell me when the system matrix be factorized 
> > (incompletely)? thank you.
>
>
> During a call of KSPSetUp().
>
> Hong
>
> > Zhifeng
Thank you for your reply, since the problem I have is ICC took too much 
memory, but I think I can fix it with reorderring the matrix.

My matrix is SeqSBAIJ and ICC is used as preconditioner, I think the 
default orderring is "natural", while I think nested-dissection is what 
I need.

However, when I choose nested dissection with - 
*pc_factor_mat_ordering_type nd, this is what comes out:

[0]PETSC ERROR: 
------------------------------------------------------------------------
[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, 
probably memory access out of range
[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[0]PETSC ERROR: or see 
http://www.mcs.anl.gov/petsc/petsc-as/documentation/troubleshooting.html#Signal[0]PETSC 
ERROR: or try http://valgrind.org on linux or man libgmalloc on Apple to 
find memory corruption errors
[0]PETSC ERROR: likely location of problem given in stack below
[0]PETSC ERROR: --------------------- Stack Frames 
------------------------------------
[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
[0]PETSC ERROR: INSTEAD the line number of the start of the function
[0]PETSC ERROR: is given.
[0]PETSC ERROR: [0] SPARSEPACKfndsep line 50 src/mat/order/fndsep.c
[0]PETSC ERROR: [0] SPARSEPACKgennd line 70 src/mat/order/gennd.c
[0]PETSC ERROR: [0] MatOrdering_ND line 18 src/mat/order/spnd.c
[0]PETSC ERROR: [0] MatGetOrdering line 187 src/mat/order/sorder.c
[0]PETSC ERROR: [0] PCSetup_ICC line 113 src/ksp/pc/impls/factor/icc/icc.c
[0]PETSC ERROR: [0] PCSetUp line 778 src/ksp/pc/interface/precon.c
[0]PETSC ERROR: [0] KSPSolve line 305 src/ksp/ksp/interface/itfunc.c
[0]PETSC ERROR: --------------------- Error Message 
------------------------------------
[0]PETSC ERROR: Signal received!
[0]PETSC ERROR: 
------------------------------------------------------------------------
[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: 
------------------------------------------------------------------------
[0]PETSC ERROR: bin/main on a linux-gnu named callisto by zhifeng Fri 
Nov 2 16:00:58 2007
[0]PETSC ERROR: Libraries linked from 
/u/01/01/zhifeng/install/lib/linux-gnu-c-debug
[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: 
------------------------------------------------------------------------
[0]PETSC ERROR: User provided function() line 0 in unknown directory 
unknown file
[unset]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0

PS: which reorderring schemas are symmetric?

Thanks alot

Best regards
Zhifeng Sheng
*