PETSc version 3.16.5
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# PCPARMS

Allows the use of the parallel Algebraic Recursive Multilevel Solvers available in the package pARMS

### Options Database Keys

| -pc_parms_global | - one of ras, schur, bj
| -pc_parms_local | - one of ilu0, iluk, ilut, arms
| -pc_parms_solve_tol | - set the tolerance for local solve
| -pc_parms_levels | - set the number of levels
| -pc_parms_nonsymmetric_perm | - set the use of nonsymmetric permutation
| -pc_parms_blocksize | - set the block size
| -pc_parms_ind_tol | - set the tolerance for independent sets
| -pc_parms_max_dim | - set the inner krylov dimension
| -pc_parms_max_it | - set the maximum number of inner iterations
| -pc_parms_inter_nonsymmetric_perm | - set the use of nonsymmetric permutation for interlevel blocks
| -pc_parms_inter_column_perm | - set the use of column permutation for interlevel blocks
| -pc_parms_inter_row_scaling | - set the use of row scaling for interlevel blocks
| -pc_parms_inter_column_scaling | - set the use of column scaling for interlevel blocks
| -pc_parms_last_nonsymmetric_perm | - set the use of nonsymmetric permutation for last level blocks
| -pc_parms_last_column_perm | - set the use of column permutation for last level blocks
| -pc_parms_last_row_scaling | - set the use of row scaling for last level blocks
| -pc_parms_last_column_scaling | - set the use of column scaling for last level blocks
| -pc_parms_lfil_ilu_arms | - set the amount of fill-in for ilut, iluk and arms
| -pc_parms_lfil_schur | - set the amount of fill-in for schur
| -pc_parms_lfil_ilut_L_U | - set the amount of fill-in for ILUT L and U
| -pc_parms_droptol_factors | - set the drop tolerance for L, U, L^{-1}F and EU^{-1}
| -pc_parms_droptol_schur_compl | - set the drop tolerance for schur complement at each level
| -pc_parms_droptol_last_schur | - set the drop tolerance for ILUT in last level schur complement

### IMPORTANT

Unless configured appropriately, this preconditioner performs an inexact solve as part of the preconditioner application. Therefore, it must be used in combination with flexible variants of iterative solvers, such as KSPFGMRES or KSPGCR.

### See Also

PCCreate(), PCSetType(), PCType (for list of available types), PC

### Level

intermediate

### Location

src/ksp/pc/impls/parms/parms.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages