<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sun, May 21, 2017 at 11:11 AM, Franck Houssen <span dir="ltr"><<a href="mailto:franck.houssen@inria.fr" target="_blank">franck.houssen@inria.fr</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-family:times new roman,new york,times,serif;font-size:12pt;color:#000000"><div>When using <a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCShellSetApply.html," target="_blank">http://www.mcs.anl.gov/petsc/<wbr>petsc-current/docs/<wbr>manualpages/PC/<wbr>PCShellSetApply.html,</a> do I have the guaranty that xout from "<a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Sys/PetscErrorCode.html#PetscErrorCode" target="_blank">PetscErrorCode</a> apply (<a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PC.html#PC" target="_blank">PC</a> pc,<a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/Vec.html#Vec" target="_blank">Vec</a> xin,<a href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Vec/Vec.html#Vec" target="_blank">Vec</a> xout)" has always been previously filled with zeros ?<br></div><div>I may have to fill xout by blocks (I would += several possibly overlapping blocks: I need to make sure xout is first filled with zero to get the correct result).<span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888"><div><span style="font-size:12pt"></span></div></font></span></div></div></blockquote><div><br></div><div>No, we do not initialize the output vector. Yo ucan call VecSet(xout, 0.0);</div><div><br></div><div>  Thanks,</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"><div><div style="font-family:times new roman,new york,times,serif;font-size:12pt;color:#000000"><span class="HOEnZb"><font color="#888888"><div><span style="font-size:12pt">Franck</span><br></div></font></span></div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><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>-- Norbert Wiener</div><div class="gmail_signature" data-smartmail="gmail_signature"><br></div><div class="gmail_signature" data-smartmail="gmail_signature"><a href="http://www.caam.rice.edu/~mk51/">http://www.caam.rice.edu/~mk51/</a><br></div></div></div>
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