ILUDropTolerance is not compatible with Mat re-ordering??

[Barry Smith]

    PETSc has currently very little support for drop tolerance ILU.  
ILU is the bane of any decent mathematicians existence.

    There isn't support for a reordering.

    Hong is actually working on much better, more general and more  
complete ILUdt that should be ready in a couple of
months. (Yes, Hong has gone over to the dark side of mathematics :-)).

    Barry

On May 7, 2009, at 8:19 PM, Rui Wang wrote:

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