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# TAOBQNKTL
Bounded Quasi-Newton-Krylov Trust-region with Line-search fallback, for nonlinear minimization with bound constraints. This method approximates the Hessian-vector product using a limited-memory quasi-Newton formula, and iteratively inverts the Hessian with a Krylov solver. The quasi-Newton matrix and its settings can be accessed via the prefix `-tao_bqnk_`. For options database, see `TAOBNK` 


## See Also
 `Tao`, `TaoType`, `TAOBNK`, `TAOBQNKTR`, `TAOBQNKLS`

## Level
beginner

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/tao/bound/impls/bqnk/bqnktl.c.html#TAOBQNKTL">src/tao/bound/impls/bqnk/bqnktl.c</A>


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