:orphan:
# TaoIsObjectiveAndGradientDefined
Checks to see if the user has declared a joint objective/gradient routine.  Useful for determining when it is appropriate to call `TaoComputeObjective()` or `TaoComputeObjectiveAndGradient()` 
## Synopsis
```
#include "petsctao.h" 
PetscErrorCode TaoIsObjectiveAndGradientDefined(Tao tao, PetscBool *flg)
```
Not Collective


## Input Parameter

- ***tao -*** the `Tao` context



## Output Parameter

- ***flg -*** `PETSC_TRUE` if function routine is set by user, `PETSC_FALSE` otherwise





## See Also
 [](ch_tao), `TaoSetObjectiveAndGradient()`, `TaoIsObjectiveDefined()`, `TaoIsGradientDefined()`

## Level
developer

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


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


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