:orphan:
# SNESMonitorResidual
Monitors progress of the `SNES` solvers by calling `VecView()` for the residual at each iteration. 
## Synopsis
```
#include "petsc/private/snesimpl.h"   
PetscErrorCode SNESMonitorResidual(SNES snes, PetscInt its, PetscReal fgnorm, PetscViewerAndFormat *vf)
```
Collective


## Input Parameters

- ***snes -*** the `SNES` context
- ***its -*** iteration number
- ***fgnorm -*** 2-norm of residual
- ***dummy -*** a viewer



## Options Database Key

- ***-snes_monitor_residual [ascii binary draw][:filename][:viewer format] -*** plots residual (not its norm) at each iteration





## Note
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
 [](ch_snes), `SNES`, `SNESMonitorSet()`, `SNESMonitorDefault()`, `VecView()`, `SNESMonitor()`

## Level
intermediate

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/snes/interface/snesut.c.html#SNESMonitorResidual">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](/manualpages/index.md)  
[Index of all manual pages](/manualpages/singleindex.md)