petsc-3.7.3 2016-07-24
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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 on Vec

### Input Parameter

| 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

VecNorm(), VecStrideGather(), VecStrideScatter(), VecStrideMin(), VecStrideMax()

Level:advanced
Location: src/vec/vec/utils/vinv.c
Index of all Vec routines
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Index of all manual pages