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# KSPSetConvergedNegativeCurvature
Allows to declare convergence and return `KSP_CONVERGED_NEG_CURVE` when negative curvature is detected 
## Synopsis
```
#include "petscksp.h" 
PetscErrorCode KSPSetConvergedNegativeCurvature(KSP ksp, PetscBool flg)
```
Collective


## Input Parameters

- ***ksp   -*** iterative context
- ***flg   -*** the Boolean value



## Options Database Key

- ***-ksp_converged_neg_curve <bool> -*** Declare convergence if negative curvature is detected





## Notes
This is currently used only by a subset of the Krylov solvers, namely `KSPCG`, `KSPSTCG`, `KSPQCG`, `KSPGLTR`, `KSPNASH`, and `KSPMINRES`.


## See Also
 [](ch_ksp), `KSP`, `KSPConvergedReason`, `KSPGetConvergedNegativeCurvature()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/ksp/ksp/interface/iterativ.c.html#KSPSetConvergedNegativeCurvature">src/ksp/ksp/interface/iterativ.c</A>


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


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