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# VecStrideNormAll
Computes the norms of subvectors of a vector defined by a starting point and a stride. 
## Synopsis
```
#include "petscvec.h" 
PetscErrorCode VecStrideNormAll(Vec v, NormType ntype, PetscReal nrm[])
```
Collective


## Input Parameters

- ***v -*** the vector
- ***ntype -*** type of norm, one of `NORM_1`, `NORM_2`, `NORM_INFINITY`



## Output Parameter

- ***nrm -*** the norms





## Notes
One must call `VecSetBlockSize()` before this routine to set the stride
information, or use a vector created from a multicomponent `DMDA`.

If x is the array representing the vector x then this computes the norm
of the array (x[start],x[start+stride],x[start+2*stride], ....) for each start < stride

The dimension of nrm must be the same as the vector block size

This will only work if the desire subvector is a stride subvector


## See Also
 `Vec`, `VecNorm()`, `VecStrideGather()`, `VecStrideScatter()`, `VecStrideMin()`, `VecStrideMax()`

## Level
advanced

## Location
<A HREF="PETSC_DOC_OUT_ROOT_PLACEHOLDER/src/vec/vec/utils/vinv.c.html#VecStrideNormAll">src/vec/vec/utils/vinv.c</A>


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[Edit on GitLab](https://gitlab.com/petsc/petsc/-/edit/release/src/vec/vec/utils/vinv.c)


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