# SNESMonitorJacUpdateSpectrum
Monitors the spectrun of the change in the Jacobian from the last Jacobian evaluation 
## Synopsis
```
#include "petsc/private/snesimpl.h"   
PetscErrorCode SNESMonitorJacUpdateSpectrum(SNES snes, PetscInt it, PetscReal fnorm, PetscViewerAndFormat *vf)
```
Collective on snes


## Input Parameters

- ***snes -*** the `SNES` context
- ***its -*** iteration number
- ***fgnorm -*** 2-norm of residual
- ***vf -*** viewer and format structure



## Option Database Key

- ***-snes_monitor_jacupdate_spectrum -*** activates this monitor



## Notes
This routine prints the eigenvalues of the difference in the Jacobians

This is not called directly by users, rather one calls `SNESMonitorSet()`, with this function as an argument, to cause the monitor
to be used during the `SNES` solve.




## See Also
 `SNESMonitorSet()`, `SNESMonitorSolution()`, `SNESMonitorRange()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/interface/snesut.c.html#SNESMonitorJacUpdateSpectrum">src/snes/interface/snesut.c</A>


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


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