:orphan:
# TSComputeIHessianProductFunctionUU
Runs the user-defined vector-Hessian-vector product function for Fuu. 
## Synopsis
```
#include "petscts.h"  
PetscErrorCode TSComputeIHessianProductFunctionUU(TS ts, PetscReal t, Vec U, Vec *Vl, Vec Vr, Vec *VHV)
```
Collective


## Input Parameters

- ***ts   -*** The `TS` context obtained from `TSCreate()`
- ***t -*** the time
- ***U -*** the solution at which to compute the Hessian product
- ***Vl -*** the array of input vectors to be multiplied with the Hessian from the left
- ***Vr -*** the input vector to be multiplied with the Hessian from the right



## Output Parameter

- ***VhV -*** the array of output vectors that store the Hessian product





## Note
`TSComputeIHessianProductFunctionUU()` is typically used for sensitivity implementation,
so most users would not generally call this routine themselves.


## See Also
 [](ch_ts), `TSSetIHessianProduct()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/interface/sensitivity/tssen.c.html#TSComputeIHessianProductFunctionUU">src/ts/interface/sensitivity/tssen.c</A>


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


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