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# TSAlphaSetParams
sets the algorithmic parameters for `TSALPHA` 
## Synopsis
```
#include "petscts.h"   
PetscErrorCode TSAlphaSetParams(TS ts, PetscReal alpha_m, PetscReal alpha_f, PetscReal gamma)
```
Logically Collective


## Second-order accuracy can be obtained so long as
\gamma = 0.5 + alpha_m - alpha_f


## Unconditional stability requires
\alpha_m >= \alpha_f >= 0.5


## Backward Euler method is recovered with
\alpha_m = \alpha_f = gamma = 1


## Input Parameters

- ***ts -*** timestepping context
- ***alpha_m -*** algorithmic parameter
- ***alpha_f -*** algorithmic parameter
- ***gamma   -*** algorithmic parameter



## Options Database Keys

- ***-ts_alpha_alpha_m <alpha_m> -*** set alpha_m
- ***-ts_alpha_alpha_f <alpha_f> -*** set alpha_f
- ***-ts_alpha_gamma   <gamma> -*** set gamma





## Note
Use of this function is normally only required to hack `TSALPHA` to
use a modified integration scheme. Users should call
`TSAlphaSetRadius()` to set the desired spectral radius of the methods
(i.e. high-frequency damping) in order so select optimal values for
these parameters.


## See Also
 [](ch_ts), `TS`, `TSALPHA`, `TSAlphaSetRadius()`, `TSAlphaGetParams()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/alpha/alpha1.c.html#TSAlphaSetParams">src/ts/impls/implicit/alpha/alpha1.c</A>

## Implementations

<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/impls/implicit/alpha/alpha1.c.html#TSAlphaSetParams_Alpha">TSAlphaSetParams_Alpha in src/ts/impls/implicit/alpha/alpha1.c</A><BR>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/ts/impls/implicit/alpha/alpha1.c)


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