KSPFlexibleModifyPCKSP — PETSc 3.25.2 documentation

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# KSPFlexibleModifyPCKSP

modifies the attributes of the `PCKSP` preconditioner, see Flexible Krylov Methods.

## Synopsis

    #include "petscksp.h"
    PetscErrorCode KSPFlexibleModifyPCKSP(KSP ksp, PetscInt total_its, PetscInt loc_its, PetscReal res_norm, PetscCtx ctx)

## Input Parameters

- ksp - the ksp context being used.

- total_its - the total number of `KSP` iterations that have occurred.

- loc_its - the number of `KSP` iterations since last restart.

- res_norm - the current residual norm.

- ctx - context, unused in this routine

## Notes

You can use this as a template for writing a custom modification callback. See the source code for the change it makes.

You can provide this to a `KSP` with `KSPFlexibleSetModifyPC()`

## See Also

KSP: Linear System Solvers, Flexible Krylov Methods, `KSPFGMRES`, `KSPFCG`, `KSPPIPEFCG`, `KSPGCR`, `KSPPIPEGCR`, `KSPFlexibleModifyPCFn`, `KSPFlexibleSetModifyPC()`

## Level

intermediate

## Location

src/ksp/ksp/impls/gmres/fgmres/modpcf.c

Index of all KSP routines
Table of Contents for all manual pages
Index of all manual pages