ILUDropTolerance is not compatible with Mat re-ordering??

Rui Wang ruiwang2 at
Thu May 7 20:19:33 CDT 2009

Dear All,

      I am trying very hard to use PCILUSetUseDropTolerance() together with PCILUSetMatOrdering(), but it does not work, no matter what kind of MatOrderingType (RCM, ND...) i choose. The message I got:

Note: The EXACT line numbers in the stack are not available,
      INSTEAD the line number of the start of the function
      is given.
[0] MatILUDTFactor_SeqAIJ line 66 src/mat/impls/aij/seq/aijfact.c
[0] MatILUDTFactor line 1362 src/mat/interface/matrix.c
[0] PCSetUp_ILU line 568 src/sles/pc/impls/ilu/ilu.c
[0] PCSetUp line 756 src/sles/pc/interface/precon.c
[0] SLESSolve line 466 src/sles/interface/sles.c
[0]PETSC ERROR: unknownfunction() line 0 in  unknown file
[0] MPI Abort by user Aborting program !
[0] Aborting program!
p0_32609:  p4_error: : 59

    I spent a lot of time on this and still cannot figure it out.

   Actually if I just use PCILUSetUseDropTolerance() itself, it works fine. Also,  if I choose other ILU methods such as level-based ILU, PCILUSetMatOrdering() works perfectly with them.

    I wonder how to use ILUDropTolerance together with the reordering technique (such as RCM)? or they are not compatible?
BTW, my PETSc version is 2.1.0. Is this because i am using this old version?

    Thanks a lot.

Rui Wang


Rui Wang
Ph.D. Candidate
Research Assistant and Predoctoral Fellow
Department of Electrical and Computer Engineering
University of Illinois at Urbana-Champaign

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