:orphan:
# PCGetDiagonalScale
Indicates if the preconditioner applies an additional left and right scaling as needed by certain time-stepping codes. 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode PCGetDiagonalScale(PC pc, PetscBool *flag)
```
Logically Collective


## Input Parameter

- ***pc -*** the preconditioner context



## Output Parameter

- ***flag -*** `PETSC_TRUE` if it applies the scaling





## Note
If this returns `PETSC_TRUE` then the system solved via the Krylov method is
```none
      D M A D^{-1} y = D M b  for left preconditioning or
      D A M D^{-1} z = D b for right preconditioning
```



## See Also
 `PC`, `PCCreate()`, `PCSetUp()`, `PCDiagonalScaleLeft()`, `PCDiagonalScaleRight()`, `PCSetDiagonalScale()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/interface/precon.c.html#PCGetDiagonalScale">src/ksp/pc/interface/precon.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ksp/pc/interface/precon.c)


[Index of all PC routines](index.md)  
[Table of Contents for all manual pages](/manualpages/index.md)  
[Index of all manual pages](/manualpages/singleindex.md)