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# KSPGetComputeSingularValues
Gets the flag indicating whether the extreme singular values will be calculated via a Lanczos or Arnoldi process as the linear system is solved. 
## Synopsis
```
#include "petscksp.h" 
#include "petscmat.h" 
PetscErrorCode KSPGetComputeSingularValues(KSP ksp, PetscBool *flg)
```
Not Collective


## Input Parameter

- ***ksp -*** iterative context obtained from `KSPCreate()`



## Output Parameter

- ***flg -*** `PETSC_TRUE` or `PETSC_FALSE`



## Options Database Key

- ***-ksp_monitor_singular_value -*** Activates `KSPSetComputeSingularValues()`



## Notes
Currently this option is not valid for all iterative methods.

Many users may just want to use the monitoring routine
`KSPMonitorSingularValue()` (which can be set with option -ksp_monitor_singular_value)
to print the singular values at each iteration of the linear solve.




## See Also
 [](ch_ksp), `KSPComputeExtremeSingularValues()`, `KSPMonitorSingularValue()`, `KSP`

## Level
advanced

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


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