Re: pc_factor_fill

[Waad Subber <w_subber@xxxxxxxxx>]

Thanks Barry

One more question please:

Should I get and set the fill factor  like this:

      call MatGetInfo(A,MAT_LOCAL,info,ierr)
      FACTFILL = info(MAT_INFO_fill_ratio_needed)
      call PCFactorSetFill(pc,FACTFILL,ierr)
      call ISSetPermutation(indexSet,IERR);CHKERRQ(IERR)
      call MatLUFactorSymbolic(A,indexSet,indexSet,FACTFILL,... 
      call MatLUFactorNumeric(A,FACTFILL,factorMat,IERR)

Thanks

Waad

Barry Smith <bsmith@xxxxxxxxxxx> wrote:

  PCFactorSetFill() after calling KSPSetPC()

   Barry

  If you are using multiple different KSP's you might look at KSPSetOptionsPrefix()

to allow using command line options to set different values for different solvers.

On Nov 22, 2007, at 5:46 AM, Waad Subber wrote:

Hello PETSc Users,

I have a serial code to solve multiple matrices. I am using LU factorization. When I run the code  with the (-info) option, it gives me different values for (pc_factor_fill) depending on the input matrix. I am wondering if I can set these values for the (pc_factor_fill) inside the code instead of running it with runtime option, for it is one code with multiple inputs.

Thanks a lot

Waad


For Matrix No.1

[5] MatLUFactorSymbolic_SeqAIJ(): Reallocs 3 Fill ratio:given 0 needed 2.96
[5] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 2.96 or use
[5] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,2.96);
[5] MatLUFactorSymbolic_SeqAIJ(): for best performance.

For Matrix No.2

[9] MatLUFactorSymbolic_SeqAIJ(): Reallocs 3 Fill ratio:given 0 needed 2.42069
[9] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 2.42069 or use
[9] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,2.42069);
[9] MatLUFactorSymbolic_SeqAIJ(): for best performance.

For Matrix No. n

[8] MatLUFactorSymbolic_SeqAIJ(): Reallocs 3 Fill ratio:given 0 needed 1.87742
[8] MatLUFactorSymbolic_SeqAIJ(): Run with -pc_factor_fill 1.87742 or use
[8] MatLUFactorSymbolic_SeqAIJ(): PCFactorSetFill(pc,1.87742);
[8] MatLUFactorSymbolic_SeqAIJ(): for best performance.

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