# PCDiagonalScale

Indicates if the preconditioner applies an additional left and right scaling as needed by certain time-stepping codes.

### Synopsis

    #include "petscksp.h"
    PetscErrorCode PETSCKSP_DLLEXPORT PCDiagonalScale(PC pc,PetscTruth *flag)

Collective on PC

### Input Parameter

pc -the preconditioner context

### Output Parameter

flag -PETSC_TRUE if it applies the scaling

Notes: If this returns PETSC_TRUE then the system solved via the Krylov method is

              D M A D^{-1} y = D M b  for left preconditioning or

              D A M D^{-1} z = D b for right preconditioning

### Keywords

PC

### See Also

PCCreate(), PCSetUp(), PCDiagonalScaleLeft(), PCDiagonalScaleRight(), PCDiagonalScaleSet()

Level:developer
Location:src/ksp/pc/interface/precon.c
Index of all PC routines
Table of Contents for all manual pages
Index of all manual pages