[petsc-users] PETSc equivalent to PGMRES

[Hong Zhang]

Scott:

> We have been using Yousef Saad's PGMRES with the ILUT pre-conditioner with
> drop tolerance of 0.01 and lfil of 100.
>
> What specific settings/calls are needed in PETSc to achieve the equivalent
> of this previous solution scheme?

Your can use superlu's ILUT through PETSc, for example,
src/ksp/ksp/examples/tutorials>./ex2 -pc_type ilu
-pc_factor_mat_solver_package superlu -mat_superlu_ilu_droptol 0.01
Norm of error 0.000544426 iterations 2

Running an example with '-help |grep superlu' lists all available options
  -mat_superlu_ilu_droptol <0.0001>: ILU_DropTol (None)
  -mat_superlu_ilu_filltol <0.01>: ILU_FillTol (None)
  -mat_superlu_ilu_fillfactor <10>: ILU_FillFactor (None)
  -mat_superlu_ilu_droprull <9>: ILU_DropRule (None)
  -mat_superlu_ilu_norm <2>: ILU_Norm (None)
  -mat_superlu_ilu_milu <0>: ILU_MILU (None)

Note: you must configure petsc with superlu. See
http://www.mcs.anl.gov/petsc/petsc-as/miscellaneous/external.html

Hong
>
> Scott Ormiston
>