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# TSGetCostHessianProducts

Returns the gradients from the `TSAdjointSolve()`

## Synopsis

    #include <petscts.h>
    PetscErrorCode TSGetCostHessianProducts(TS ts, PetscInt *numcost, Vec *lambda2[], Vec *mu2[], Vec *dir)

Not Collective, but vectors returned are parallel if `TS` is parallel

## Input Parameter

- ts - the `TS` context obtained from `TSCreate()`

## Output Parameters

- numcost - number of cost functions

- lambda2 - Hessian-vector product with respect to the initial condition variables, the dimension and parallel layout of these vectors is the same as the ODE solution vector

- mu2 - Hessian-vector product with respect to the parameters, the number of entries in these vectors is the same as the number of parameters

- dir - the direction vector that are multiplied with the Hessian of the cost functions

## See Also

TS: Scalable ODE and DAE Solvers, `TSAdjointSolve()`, `TSSetCostHessianProducts()`

## Level

intermediate

## Location

src/ts/interface/sensitivity/tssen.c

Index of all Sensitivity routines
Table of Contents for all manual pages
Index of all manual pages