# TAOBQNLS
Bounded Quasi-Newton Line Search method for nonlinear minimization with bound constraints. This method approximates the action of the inverse-Hessian with a limited memory quasi-Newton formula. The quasi-Newton matrix and its options are accessible via the prefix `-tao_bqnls_` 
## Option Database Keys

- ***-tao_bnk_max_cg_its -*** maximum number of bounded conjugate-gradient iterations taken in each Newton loop
- ***-tao_bnk_as_type -*** active-set estimation method ("none", "bertsekas")
- ***-tao_bnk_epsilon -*** (developer) tolerance for small pred/actual ratios that trigger automatic step acceptance
- ***-tao_bnk_as_tol -*** (developer) initial tolerance used in estimating bounded active variables (-as_type bertsekas)
- ***-tao_bnk_as_step -*** (developer) trial step length used in estimating bounded active variables (-as_type bertsekas)




## See Also
 `TAOBNK`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/bound/impls/bqnls/bqnls.c.html#TAOBQNLS">src/tao/bound/impls/bqnls/bqnls.c</A>

## Examples
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ts/tutorials/ex20opt_p.c.html">src/ts/tutorials/ex20opt_p.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/burgers_spectral.c.html">src/tao/unconstrained/tutorials/burgers_spectral.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/rosenbrock3.c.html">src/tao/unconstrained/tutorials/rosenbrock3.c.html</A><BR>
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/unconstrained/tutorials/spectraladjointassimilation.c.html">src/tao/unconstrained/tutorials/spectraladjointassimilation.c.html</A><BR>


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


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