<div dir="ltr"><div>Dear all,</div><div><br></div>Thank you for your answers.<div>Do you know which options are required for a typical use case of GDSW in PCMG? However, I imagine that only structured DMDA meshes can be employed with it.</div><div><br></div><div>Best,</div><div>Edoardo</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">Il giorno mer 21 mag 2025 alle ore 16:52 Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div><br></div><div> Thanks for your interest in this type of algorithm.</div><div><br></div> As Pierre notes, the code is implemented only as a simple tutorial on one particular "exotic" wire basket-type algorithm. We don't recommend this implementation for more general algorithms or geometries. <div><br></div><div> The face dof represents some sort of "average" of the face solution, it is not a point value.</div><div><br></div><div> Barry</div><div><br id="m_-8772001589112487393lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On May 21, 2025, at 4:51 AM, Pierre Jolivet <<a href="mailto:pierre@joliv.et" target="_blank">pierre@joliv.et</a>> wrote:</div><br><div><div dir="auto"><div dir="ltr"></div><div dir="ltr"><br></div><div dir="ltr"><br><blockquote type="cite">On 21 May 2025, at 10:41 AM, Edoardo Centofanti <<a href="mailto:edoardo.centofanti01@universitadipavia.it" target="_blank">edoardo.centofanti01@universitadipavia.it</a>> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><div dir="ltr"><div>Dear all,</div><div><br></div><div>I have some questions about the PCEXOTIC preconditioner:</div><div><br></div><div>1- While the type "wirebasket" seems clear to me, I do not understand what is meant as "one dof per face" in the documentation referring to "face" type. Is it intended as the interpolation on the centre of the face or some mean value?</div><div><br></div><div>2- Is it possible to change the overlap between the subdomains?</div><div><br></div><div>3- Are there any plans of extending the implementation to unstructured grids (DMPlex-like)? The current one seems to rely heavily on DMDA</div><div><br></div><div>4- Running some preliminary tests on GPU with a code of mine that works on CPU, I got the following error:</div><div><br></div><div> ** On entry to cusparseSpMM_bufferSize(): dimension mismatch, matA.num_rows (15405) != matC.num_rows (44955) with opA = CUSPARSE_OPERATION_NON_TRANSPOSE</div><div><br></div><div>Is the preconditioner intended to run also on GPU or the error above comes from the fact that this feature has yet to be tested/fully implemented?</div><div><br></div></div></div></blockquote><div><br></div><div>This preconditioner is very old and the code is barely maintained.</div><div>There is a newer implementation of the GDSW preconditioner in PCMG, see <a href="https://urldefense.us/v3/__https://petsc.org/release/manualpages/PC/PCMGSetAdaptCoarseSpaceType/__;!!G_uCfscf7eWS!ZDnv3udGFNlZEC_MRfLAqwvcvCObnaAjMCeyaW__UaecBvN3MkXrzOPwJJUSHXo80-xOQdLNnSf_nLmUd7bZxg$" target="_blank">https://petsc.org/release/manualpages/PC/PCMGSetAdaptCoarseSpaceType/</a></div><div><br></div><div>Thanks,</div><div>Pierre</div><br><blockquote type="cite"><div dir="ltr"><div dir="ltr"><div>Thank you in advance,</div><div>Best,</div><div>Edoardo</div><div><br></div><div dir="ltr" class="gmail_signature"></div></div>
</div></blockquote></div></div></blockquote></div><br></div></div></blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><table style="color:rgb(25,28,43);font-family:Mulish,sans-serif;font-size:16px;direction:ltr;border-collapse:collapse"><tbody><tr><td style="font-size:0px;height:12px;line-height:0px"></td></tr><tr><td><table cellpadding="0" cellspacing="0" style="border-collapse:collapse;font-family:Arial;line-height:1.15;color:rgb(0,0,0)"><tbody><tr><td style="vertical-align:top;padding:0.01px 14px 0.01px 1px;width:65px;text-align:center"><img src="https://d36urhup7zbd7q.cloudfront.net/a/fb15e67f-e745-4930-b710-e6f89dfe45b0.png" height="83.61186717474143" width="65" style="width: 65px; vertical-align: middle; border-radius: 0px; height: 83.6119px;"></td><td valign="top" style="padding:0.01px 0.01px 0.01px 14px;vertical-align:top;border-left:1px solid rgb(189,189,189)"><table cellpadding="0" cellspacing="0" style="border-collapse:collapse"><tbody><tr><td style="line-height:1.2;padding:0.01px"><span style="text-transform:initial;letter-spacing:0px;line-height:1.2"><font color="#cc0000" size="2">Edoardo Centofanti</font></span><br><span style="text-transform:initial;line-height:1.2"><font color="#cc0000" size="1">Dipartimento di Matematica 'Felice Casorati'<br>Università degli Studi di Pavia</font></span></td></tr><tr><td><table cellpadding="0" cellspacing="0" style="border-collapse:collapse"><tbody><tr><td nowrap width="421" style="padding-top:14px;width:421px"><p style="margin:0.1px;line-height:1"><span style="font-size:11px;color:rgb(33,33,33)">Tel. 0382985608 | Ufficio A14 | <a href="https://urldefense.us/v3/__https://maps.google.com/?q=Via*20Ferrata*205,*2027100*20Pavia,*20Italy__;JSUlJSU!!G_uCfscf7eWS!Zmi6sdgeoCOMy1lkVGYn-ac5wvH3QEcOkYQ2VzdQgCqLY8nIVkX1oi_yt5S2vJDcF5BT8mmzOLmOUEK483D0v9_aZe01iy1b20hMoN_kNHg$" rel="nofollow noreferrer" style="color:rgb(17,85,204);text-decoration:unset" target="_blank"><span style="line-height:1.2;color:rgb(33,33,33)">Via Ferrata 5, 27100 Pavia, Italy</span></a></span></p></td></tr></tbody></table></td></tr></tbody></table></td></tr></tbody></table></td></tr></tbody></table></div></div>