:orphan:
# SNESSetTolerances
Sets `SNES` various parameters used in convergence tests. 
## Synopsis
```
#include "petscsnes.h"  
PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
```
Logically Collective


## Input Parameters

- ***snes -*** the `SNES` context
- ***abstol -*** absolute convergence tolerance
- ***rtol -*** relative convergence tolerance
- ***stol -*** convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
- ***maxit -*** maximum number of iterations, default 50.
- ***maxf -*** maximum number of function evaluations (-1 indicates no limit), default 1000



## Options Database Keys

- ***-snes_atol <abstol> -*** Sets abstol
- ***-snes_rtol <rtol> -*** Sets rtol
- ***-snes_stol <stol> -*** Sets stol
- ***-snes_max_it <maxit> -*** Sets maxit
- ***-snes_max_funcs <maxf> -*** Sets maxf





## See Also
 [](ch_snes), `SNESolve()`, `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/interface/snes.c.html#SNESSetTolerances">src/snes/interface/snes.c</A>


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