[petsc-users] petsc KLU

[Romain Thomas]

Hi,
Thank you for your answer.
My problem is a bit more complex. During the simulation (“real time”), I need to upgrade at each time step the matrix A and the MatassemblyBegin and MatassemblyEnd take time and so, in order to avoid these functions, I don’t use ksp or pc. I prefer to use the functions MatLUFactorNumeric, MatLUFactorSymbolic and MatLUFactor. And so, I want to know if there is similar functions for KLU. (I tried for Cholesky and, iLU and it works well).
Best regards,
Romain


From: Matthew Knepley [mailto:knepley at gmail.com]
Sent: vrijdag 14 augustus 2015 16:41
To: Romain Thomas
Cc: petsc-users at mcs.anl.gov
Subject: Re: [petsc-users] petsc KLU

On Fri, Aug 14, 2015 at 9:23 AM, Romain Thomas <R.Thomas at tudelft.nl<mailto:R.Thomas at tudelft.nl>> wrote:
Dear PETSc users,

I would like to know if I can replace the following functions

MatLUFactorNumeric(Mat fact,Mat mat,const MatFactorInfo *info)
MatLUFactorSymbolic(Mat fact,Mat mat,IS row,IS col,const MatFactorInfo *info)
MatLUFactor(Mat mat,IS row,IS col,const MatFactorInfo *info)

by

MatLUFactorNumeric_KLU(Mat F,Mat A,const MatFactorInfo *info)
MatLUFactorSymbolic_KLU(Mat F,Mat A,IS r,IS c,const MatFactorInfo *info)
MatGetFactor_seqaij_klu(Mat A,MatFactorType ftype,Mat *F)

in my code for the simulation of electrical power systems? (I installed the package SuiteSparse)

Why would you do that? It already works with the former code. In fact, you should really just use

  KSPCreate(comm, &ksp)
  KSPSetOperator(ksp, A, A);
  KSPSetFromOptions(ksp);
  KSPSolve(ksp, b, x);

and then give the options

  -ksp_type preonly -pc_type lu -pc_mat_factor_package suitesparse

This is no advantage to using the Factor language since subsequent calls to
KSPSolve() will not refactor.

   Matt

Thank you,
Best regards,
Romain



--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener
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