[petsc-users] VecStrideScatter question

[Jed Brown]

Tabrez Ali <stali at geology.wisc.edu> writes:

> Hello
>
> I have two parallel vectors (same layout) of different lengths, e.g.,
>
> V1=[u1 v1 w1 u2 v2 w2 u3 v3 w3]' and
> V2=[x1 x2 x3]'
>
> and I wish to add them in a way such that
>
> V3=[
> u1
> v1
> w1+x1
> u2
> v2
> w2+x2
> u3
> v3
> w3+x3
> ]
>
> Is VecStrideScatter appropriate for this? I tried
>
> call VecStrideScatter(V2,3,V1,Add_Values,ierr)
>
> but it seems to fail.

"seems to fail" is not helpful, but in any case, the indexing starts at
0 (so pass 2 instead of 3).