# TSSundialsSetTolerance
Sets the absolute and relative tolerance used by `TSSUNDIALS` for error control. 
## Synopsis
```
#include "petscts.h" 
PetscErrorCode TSSundialsSetTolerance(TS ts, PetscReal aabs, PetscReal rel)
```
Logically Collective


## Input Parameters

- ***ts  -*** the time-step context
- ***aabs -*** the absolute tolerance
- ***rel -*** the relative tolerance


See the CVODE/SUNDIALS users manual for exact details on these parameters. Essentially
these regulate the size of the error for a SINGLE timestep.




## See Also
 [](chapter_ts), `TSSundialsGetIterations()`, `TSSundialsSetType()`, `TSSundialsSetGMRESMaxl()`,
`TSSundialsSetLinearTolerance()`, `TSSundialsSetGramSchmidtType()`,
`TSSundialsGetIterations()`, `TSSundialsSetType()`,
`TSSundialsSetLinearTolerance()`, `TSSundialsSetTolerance()`, `TSSundialsGetPC()`,
`TSSetExactFinalTime()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/sundials/sundials.c.html#TSSundialsSetTolerance">src/ts/impls/implicit/sundials/sundials.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/sundials/sundials.c.html#TSSundialsSetTolerance_Sundials">TSSundialsSetTolerance_Sundials in src/ts/impls/implicit/sundials/sundials.c</A><BR>


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


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