:orphan:
# SNESNewtonTRFallbackType
type of fallback in case the solution of the trust-region subproblem is outside of the radius 
## Synopsis
```
typedef enum {
  SNES_TR_FALLBACK_NEWTON,
  SNES_TR_FALLBACK_CAUCHY,
  SNES_TR_FALLBACK_DOGLEG,
} SNESNewtonTRFallbackType;
```

## Values

- ***`SNES_TR_FALLBACK_NEWTON` -*** use scaled Newton step
- ***`SNES_TR_FALLBACK_CAUCHY` -*** use Cauchy direction
- ***`SNES_TR_FALLBACK_DOGLEG` -*** use dogleg method





## See Also
 [](ch_snes), `SNES`, `SNESNEWTONTR`, `SNESNEWTONTRDC`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/include/petscsnes.h.html#SNESNewtonTRFallbackType">include/petscsnes.h</A>


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[Index of all SNES routines](index.md)  
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