<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 19 Oct 2022, at 4:32 PM, TARDIEU Nicolas <<a href="mailto:nicolas.tardieu@edf.fr" class="">nicolas.tardieu@edf.fr</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta charset="UTF-8" class=""><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Dear Pierre,</div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;"><br class=""></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Thank you very much for your answer. I have the same explanation as you for the code I sent. </div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div class="elementToProof" style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">But what I would like to do is the following : I have the full matrix A with fields u, p and t (which are interlaced in the real application). I want to extract B=A(u+p, u+p). *Then* I would like to extract the (u, u) block from B - let us call it B_uu.</div><div class="elementToProof" style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">In fact, B_uu=A_uu but I really need to do the extraction from B.</div><div class="elementToProof" style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">And I am missing something since I have to play with different numberings when switching the IS from A to B.</div><div id="Signature" class=""><div class=""><div name="divtagdefaultwrapper" style="font-family: Calibri, Arial, Helvetica, sans-serif; margin: 0px;" class=""></div><div name="divtagdefaultwrapper" style="font-family: Calibri, Arial, Helvetica, sans-serif; margin: 0px;" class=""><div style="margin: 0px;" class=""><font size="3" face="Calibri,sans-serif" class=""><br class=""></font></div><div style="margin: 0px;" class=""><font size="3" face="Calibri,sans-serif" class="">Is it clear enough ???? </font></div></div></div></div></div></div></blockquote><div><br class=""></div><div>That’s cristal clear.</div><div>If the fields are interlaced, that’s actually easier to do, because you preserve the distribution, and there is less data movement.</div><div>I’ll try to fix your code in the case where the fields are interlaced if now one gives you another answer in the meantime.</div><div><br class=""></div><div>Thanks,</div><div>Pierre</div><br class=""><blockquote type="cite" class=""><div class=""><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div id="Signature" class=""><div class=""><div name="divtagdefaultwrapper" style="font-family: Calibri, Arial, Helvetica, sans-serif; margin: 0px;" class=""><font size="3" class=""></font><div style="margin: 0px;" class=""><font size="3" face="Calibri,sans-serif" class="">Regards,<span class="Apple-converted-space"> </span></font></div><font size="3" class=""></font><div style="margin: 0px;" class=""><font face="Calibri,sans-serif" class=""><font size="3" class="">Nicolas<br class=""><span style="font-size: 11pt;" class="">--</span></font><br class=""></font><font size="2" face="Arial,sans-serif" color="#ff8100" class=""><span style="font-size: 9pt;" class=""><b class="">Nicolas Tardieu</b></span></font><br class=""><div style="margin: 0px;" class=""><font size="2" face="Calibri,sans-serif" class=""><span style="font-size: 11pt;" class=""><font size="1" face="Arial,sans-serif" color="#ff8100" class=""><span style="font-size: 8pt;" class=""><b class="">Ing PhD Computational Mechanics</b></span></font><font size="1" face="Arial,sans-serif" color="#ff8100" class=""><span style="font-size: 8pt;" class=""><b class=""><br class=""></b></span></font></span></font></div><div style="margin: 0px;" class=""><font size="2" face="Calibri,sans-serif" class=""><span style="font-size: 11pt;" class=""><font size="1" face="Arial,sans-serif" color="#0062e1" class=""><span lang="en-US" style="font-size: 8pt;" class="">EDF - R&D Dpt ERMES</span></font><font size="1" face="Helv,sans-serif" color="#0062e1" class=""><span lang="en-US" style="font-size: 2pt;" class=""><br class=""></span></font></span></font></div><div style="margin: 0px;" class=""><span style="font-family: Arial, sans-serif; font-size: 8pt; color: rgb(0, 98, 225); background-color: rgba(0, 0, 0, 0);" class="">PARIS-SACLAY, FRANCE</span></div></div></div></div></div></div><div id="appendonsend" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""></div><hr tabindex="-1" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline-block; width: 1146.59375px;" class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class=""></span><div id="divRplyFwdMsg" dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><font face="Calibri, sans-serif" style="font-size: 11pt;" class=""><b class="">De :</b><span class="Apple-converted-space"> </span><a href="mailto:pierre@joliv.et" class="">pierre@joliv.et</a> <<a href="mailto:pierre@joliv.et" class="">pierre@joliv.et</a>><br class=""><b class="">Envoyé :</b><span class="Apple-converted-space"> </span>mercredi 19 octobre 2022 14:51<br class=""><b class="">À :</b><span class="Apple-converted-space"> </span>TARDIEU Nicolas <<a href="mailto:nicolas.tardieu@edf.fr" class="">nicolas.tardieu@edf.fr</a>><br class=""><b class="">Cc :</b><span class="Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov" class="">petsc-users@mcs.anl.gov</a> <<a href="mailto:petsc-users@mcs.anl.gov" class="">petsc-users@mcs.anl.gov</a>><br class=""><b class="">Objet :</b><span class="Apple-converted-space"> </span>Re: [petsc-users] Trouble with ISEmbed</font><div class=""> </div></div><div class="BodyFragment" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><font size="2" class=""><span style="font-size: 11pt;" class=""><div class="PlainText">On two processes, you have a different distribution for u and u+p.<br class="">IS Object: 2 MPI processes<br class=""> type: general<br class="">[0] Number of indices in set 5<br class="">[0] 0 0<br class="">[0] 1 1<br class="">[0] 2 2<br class="">[0] 3 3<br class="">[0] 4 4<br class="">[1] Number of indices in set 5<br class="">[1] 0 5<br class="">[1] 1 6<br class="">[1] 2 7<br class="">[1] 3 8<br class="">[1] 4 9<br class="">IS Object: 2 MPI processes<br class=""> type: general<br class="">[0] Number of indices in set 8<br class="">[0] 0 0<br class="">[0] 1 1<br class="">[0] 2 2<br class="">[0] 3 3<br class="">[0] 4 4<br class="">[0] 5 5<br class="">[0] 6 6<br class="">[0] 7 7<br class="">[1] Number of indices in set 7<br class="">[1] 0 8<br class="">[1] 1 9<br class="">[1] 2 10<br class="">[1] 3 11<br class="">[1] 4 12<br class="">[1] 5 13<br class="">[1] 6 14<br class="">ISEmbed() only works on local indices, so when you embed u into u+p, on the second process, you miss the row/column indices 5, 6, 7 of B = A(u+p, u+p).<br class="">Thus, you end up with a matrix of dimension size(u) - 3 = 10 - 3 = 7, with just the row/column indices 8 and 9 being selected by the second process.<br class="">What is it that you want to do exactly? Play with ISEmbed(), or get A(u, u) without using A but B instead?<br class=""><br class="">Thanks,<br class="">Pierre<br class=""><br class="">> On 19 Oct 2022, at 12:00 PM, TARDIEU Nicolas via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov" class="">petsc-users@mcs.anl.gov</a>> wrote:<br class="">><span class="Apple-converted-space"> </span><br class="">> Dear PETSc Team,<br class="">><span class="Apple-converted-space"> </span><br class="">> I am trying to use IS embeding in parallel.<span class="Apple-converted-space"> </span><br class="">> In order to (try to) understand how it works, I have built a simple example, attached to this email.<br class="">><span class="Apple-converted-space"> </span><br class="">> I consider a 20X20 matrix. The dof (u, p, t) in global numbering are the following :<span class="Apple-converted-space"> </span><br class="">> u: 0..9 p: 10..14 t: 15..19<br class="">><span class="Apple-converted-space"> </span><br class="">> I have defined 4 IS to describe the dof u, p, t and the agglomeration of u and p, called up.<br class="">> I first extract the submatrix matrix(up,up), then I would like to extract from it the (u,u) block.<br class="">><span class="Apple-converted-space"> </span><br class="">> The example runs OK in sequential but I do not obtain the (u,u) block on 2 processes.<br class="">><span class="Apple-converted-space"> </span><br class="">> I have a mistake in the build of the sub-IS but I cannot find it for days.<br class="">><span class="Apple-converted-space"> </span><br class="">> Best regards,<br class="">> Nicolas<br class="">> --<br class="">> Nicolas Tardieu<br class="">> Ing PhD Computational Mechanics<br class="">> EDF - R&D Dpt ERMES<br class="">> PARIS-SACLAY, FRANCE<br class="">><span class="Apple-converted-space"> </span><br class="">> Ce message et toutes les pièces jointes (ci-après le 'Message') sont établis à l'intention exclusive des destinataires et les informations qui y figurent sont strictement confidentielles. 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