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# PCEisenstatGetNoDiagonalScaling
Tells if the Eisenstat preconditioner not to do additional diagonal preconditioning. For matrices with a constant along the diagonal, this may save a small amount of work. 
## Synopsis
```
#include "petscpc.h" 
PetscErrorCode PCEisenstatGetNoDiagonalScaling(PC pc, PetscBool *flg)
```
Logically Collective


## Input Parameter

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



## Output Parameter

- ***flg -*** `PETSC_TRUE` means there is no diagonal scaling applied



## Options Database Key

- ***-pc_eisenstat_no_diagonal_scaling -*** Activates `PCEisenstatSetNoDiagonalScaling()`





## Note
If you use the KSPSetDiagonalScaling() or -ksp_diagonal_scale option then you will
likely want to use this routine since it will save you some unneeded flops.


## See Also
 , `PCEISENSTAT`, `PCEisenstatGetOmega()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/eisens/eisen.c.html#PCEisenstatGetNoDiagonalScaling">src/ksp/pc/impls/eisens/eisen.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/pc/impls/eisens/eisen.c.html#PCEisenstatGetNoDiagonalScaling_Eisenstat">PCEisenstatGetNoDiagonalScaling_Eisenstat in src/ksp/pc/impls/eisens/eisen.c</A><BR>


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


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