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# KSPGetTolerances
Gets the relative, absolute, divergence, and maximum iteration tolerances used by the default `KSP` convergence tests. 
## Synopsis
```
#include "petscksp.h" 
#include "petscmat.h" 
PetscErrorCode KSPGetTolerances(KSP ksp, PetscReal *rtol, PetscReal *abstol, PetscReal *dtol, PetscInt *maxits)
```
Not Collective


## Input Parameter

- ***ksp -*** the Krylov subspace context



## Output Parameters

- ***rtol -*** the relative convergence tolerance
- ***abstol -*** the absolute convergence tolerance
- ***dtol -*** the divergence tolerance
- ***maxits -*** maximum number of iterations



## Notes
The user can specify `NULL` for any parameter that is not needed.



maximum, iterations


## See Also
 [](ch_ksp), `KSPSetTolerances()`, `KSP`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/interface/itfunc.c.html#KSPGetTolerances">src/ksp/ksp/interface/itfunc.c</A>


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


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