:orphan:
# TaoEstimateActiveBounds
Generates index sets for variables at the lower and upper bounds, as well as fixed variables where lower and upper bounds equal each other. 
## Synopsis
```
#include "petsctao.h" 
PetscErrorCode TaoEstimateActiveBounds(Vec X, Vec XL, Vec XU, Vec G, Vec S, Vec W, PetscReal steplen, PetscReal *bound_tol, IS *active_lower, IS *active_upper, IS *active_fixed, IS *active, IS *inactive)
```

## Input Parameters

- ***X -*** solution vector
- ***XL -*** lower bound vector
- ***XU -*** upper bound vector
- ***G -*** unprojected gradient
- ***S -*** step direction with which the active bounds will be estimated
- ***W -*** work vector of type and size of X
- ***steplen -*** the step length at which the active bounds will be estimated (needs to be conservative)



## Output Parameters

- ***bound_tol -*** tolerance for the bound estimation
- ***active_lower -*** index set for active variables at the lower bound
- ***active_upper -*** index set for active variables at the upper bound
- ***active_fixed -*** index set for fixed variables
- ***active -*** index set for all active variables
- ***inactive -*** complementary index set for inactive variables



## Notes
This estimation is based on Bertsekas' method, with a built in diagonal scaling value of 1.0e-3.



## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/bound/utils/isutil.c.html#TaoEstimateActiveBounds">src/tao/bound/utils/isutil.c</A>


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


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