:orphan:
# TaoKSPSetUseEW
Sets `SNES` use Eisenstat-Walker method for computing relative tolerance for linear solvers. 
## Synopsis
```
#include "petsctao.h" 
PetscErrorCode TaoKSPSetUseEW(Tao tao, PetscBool flag)
```
Logically Collective


## Input Parameters

- ***tao -*** Tao context
- ***flag -*** `PETSC_TRUE` or `PETSC_FALSE`





## Note
See `SNESKSPSetUseEW()` for customization details.


## Reference

- **** -*** S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an inexact Newton method", SISC 17 (1), pp.16-32, 1996.



## See Also
 [](ch_tao), `Tao`, `SNESKSPSetUseEW()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/interface/taosolver.c.html#TaoKSPSetUseEW">src/tao/interface/taosolver.c</A>


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


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