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# KSPGMRESSetBreakdownTolerance
Sets tolerance for determining divergence breakdown in `KSPGMRES`. 
## Synopsis
```
#include "petscksp.h"  
PetscErrorCode KSPGMRESSetBreakdownTolerance(KSP ksp, PetscReal tol)
```
Logically Collective


## Input Parameters

- ***ksp -*** the Krylov space context
- ***tol -*** the tolerance



## Options Database Key

- ***-ksp_gmres_breakdown_tolerance <positive real value> -*** set tolerance for determining divergence breakdown





## Note
Divergence breakdown occurs when GMRES residual increases significantly during restart


## See Also
 [](ch_ksp), `KSPGMRES`, `KSPSetTolerances()`, `KSPGMRESSetHapTol()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/impls/gmres/gmres.c.html#KSPGMRESSetBreakdownTolerance">src/ksp/ksp/impls/gmres/gmres.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/impls/gmres/gmres.c.html#KSPGMRESSetBreakdownTolerance_GMRES">KSPGMRESSetBreakdownTolerance_GMRES in src/ksp/ksp/impls/gmres/gmres.c</A><BR>


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


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