PETSc version 3.17.4
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# PCSetUseAmat

Sets a flag to indicate that when the preconditioner needs to apply (part of) the operator during the preconditioning process it applies the Amat provided to TSSetRHSJacobian(), TSSetIJacobian(), SNESSetJacobian(), KSPSetOperators() or PCSetOperators() not the Pmat.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode  PCSetUseAmat(PC pc,PetscBool flg)

Logically Collective on PC

### Input Parameters

| pc | - the preconditioner context
| flg | - PETSC_TRUE to use the Amat, PETSC_FALSE to use the Pmat (default is false)

### Options Database Key

| -pc_use_amat <true,false> | - use the amat to apply the operator

### Notes

For the common case in which the linear system matrix and the matrix used to construct the preconditioner are identical, this routine is does nothing.

### See Also

PCGetUseAmat(), PCBJACOBI, PGMG, PCFIELDSPLIT, PCCOMPOSITE

### Level

intermediate

### Location

src/ksp/pc/interface/precon.c
Index of all PC routines
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