# TaoSetInitialTrustRegionRadius
Sets the initial trust region radius. 
## Synopsis
```
#include "petsctao.h" 
PetscErrorCode TaoSetInitialTrustRegionRadius(Tao tao, PetscReal radius)
```
Logically Collective


## Input Parameters

- ***tao -*** a Tao optimization solver
- ***radius -*** the trust region radius





## Options Database Key

- ***-tao_trust0 <t0> -*** sets initial trust region radius



## See Also
 `TaoGetTrustRegionRadius()`, `TaoSetTrustRegionTolerance()`, `TAONTR`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/interface/taosolver.c.html#TaoSetInitialTrustRegionRadius">src/tao/interface/taosolver.c</A>


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


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