<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Franck,<div class=""><br class=""></div><div class="">PETSc takes care of doing the matrix-vector multiplication properly using MatIS. As Matt said, the layout of the vectors is the usual parallel layout.</div><div class="">The local sizes of the MatIS matrix (i.e. the local size of the left and right vectors used in MatMult) are not the sizes of the local subdomain matrices in MatIS.</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On May 21, 2017, at 6:47 PM, Matthew Knepley <<a href="mailto:knepley@gmail.com" class="">knepley@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_extra"><div class="gmail_quote">On Sun, May 21, 2017 at 11:26 AM, Franck Houssen <span dir="ltr" class=""><<a href="mailto:franck.houssen@inria.fr" target="_blank" class="">franck.houssen@inria.fr</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class=""><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;" class=""><div class="">Using PETSc MatIS, how to matmult a global IS matrix and a global vector ? Example is attached : I don't get what I expect that is a vector such that proc0 = [1, 2] and proc1 = [2, 1]</div></div></div></blockquote><div class=""><br class=""></div><div class="">1) I think the global size of your matrix is wrong. You seem to want 3, not 4</div><div class=""><br class=""></div><div class="">2) Global vectors have a non-overlapping row partition. You might be thinking of local vectors</div><div class=""><br class=""></div><div class=""> Thanks,</div><div class=""><br class=""></div><div class=""> Matt</div><div class=""> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class=""><div style="font-family: 'times new roman', 'new york', times, serif; font-size: 12pt;" class=""><span class="HOEnZb"><font color="#888888" class=""><div class="">Franck<br class=""></div></font></span></div></div></blockquote></div><br class=""><br clear="all" class=""><div class=""><br class=""></div>-- <br class=""><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr" class=""><div class="gmail_signature" data-smartmail="gmail_signature">What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br class="">-- Norbert Wiener</div><div class="gmail_signature" data-smartmail="gmail_signature"><br class=""></div><div class="gmail_signature" data-smartmail="gmail_signature"><a href="http://www.caam.rice.edu/~mk51/" class="">http://www.caam.rice.edu/~mk51/</a><br class=""></div></div></div>
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