:orphan:
# DMComputeError
Computes the error assuming the user has provided the exact solution functions 
## Synopsis
```
#include "petscdm.h"          
#include "petscdmlabel.h"     
#include "petscds.h"     
PetscErrorCode DMComputeError(DM dm, Vec sol, PetscReal errors[], Vec *errorVec)
```
Collective


## Input Parameters

- ***dm     -*** The `DM`
- ***sol    -*** The solution vector



## Input/Output Parameter

- ***errors -*** An array of length Nf, the number of fields, or `NULL` for no output; on output
contains the error in each field



## Output Parameter

- ***errorVec -*** A vector to hold the cellwise error (may be `NULL`)





## Note
The exact solutions come from the `PetscDS` object, and the time comes from `DMGetOutputSequenceNumber()`.


## See Also
 [](ch_dmbase), `DM`, `DMMonitorSet()`, `DMGetRegionNumDS()`, `PetscDSGetExactSolution()`, `DMGetOutputSequenceNumber()`

## Level
developer

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/dm/interface/dm.c.html#DMComputeError">src/dm/interface/dm.c</A>


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[Index of all DM routines](index.md)  
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