On Fri, May 28, 2010 at 1:02 PM, Yujie <span dir="ltr"><<a href="mailto:recrusader@gmail.com">recrusader@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Dear PETSc Developers,<br>
<br>
I got the following information from VecScatterCreate() manpage.<br>
"<br>
PetscErrorCode VecScatterCreate(Vec xin,IS ix,Vec yin,IS iy,VecScatter *newctx)<br>
<br>
Collective on Vec<br>
<br>
Input Parameters<br>
xin - a vector that defines the shape (parallel data layout of the<br>
vector) of vectors from which we scatter<br>
yin - a vector that defines the shape (parallel data layout of the<br>
vector) of vectors to which we scatter<br>
ix - the indices of xin to scatter (if PETSC_NULL scatters all values)<br>
iy - the indices of yin to hold results (if PETSC_NULL fills entire<br>
vector yin)<br>
"<br>
My question is about "ix". If xin and yin are parallel Vec, how about ix?<br>
<br>
Is "ix" an IS only containing local index set or a parallel IS<br>
containing all the index set on all the processors (each local index<br>
set on its processor)? Thanks a lot.<br></blockquote><div><br></div><div>ix contains some indices for that process. The indices can be different on each process.</div><div>We take the union.</div><div><br></div><div> Matt</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Regards,<br>
<font color="#888888">Yujie<br>
</font></blockquote></div><br><br clear="all"><br>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>-- Norbert Wiener<br>