# SNESNewtonTRDCPostCheck
Called after the step has been determined in `SNESNEWTONTRDC` but before the function evaluation at that step 
## Synopsis
```
#include "petscsnes.h"   
static PetscErrorCode SNESNewtonTRDCPostCheck(SNES snes, Vec X, Vec Y, Vec W, PetscBool *changed_Y, PetscBool *changed_W)
```
Logically Collective


## Input Parameters

- ***snes -*** the solver
- ***X -*** The last solution
- ***Y -*** The full step direction
- ***W -*** The updated solution, W = X - Y



## Output Parameters

- ***changed_Y -*** indicator if step has been changed
- ***changed_W -*** Indicator if the new candidate solution W has been changed.



## Note
If Y is changed then W is recomputed as X - Y




## See Also
 `SNESNEWTONTRDC`, `SNESNEWTONTRDC`, `SNESNewtonTRDCSetPostCheck()`, `SNESNewtonTRDCGetPostCheck()`, `SNESNewtonTRDCPreCheck()

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/impls/ntrdc/ntrdc.c.html#SNESNewtonTRDCPostCheck">src/snes/impls/ntrdc/ntrdc.c</A>


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


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