<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div><br></div> I apologize; please ignore my answer below. Use MatCreateShell() as indicated by Jed.<div><br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Dec 20, 2023, at 2:14 PM, Barry Smith <bsmith@petsc.dev> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><blockquote type="cite" style="font-family: Helvetica; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;">On Dec 20, 2023, at 11:44 AM, Yi Hu <y.hu@mpie.de> wrote:<br><br>Dear Jed,<br><br>Thanks for your reply. I have an analytical one to implement.<br><br>Best, Yi<br><br>-----Original Message-----<br>From: Jed Brown <jed@jedbrown.org><span class="Apple-converted-space"> </span><br>Sent: Wednesday, December 20, 2023 5:40 PM<br>To: Yi Hu <y.hu@mpie.de>; petsc-users@mcs.anl.gov<br>Subject: Re: [petsc-users] fortran interface to snes matrix-free jacobian<br><br>Are you wanting an analytic matrix-free operator or one created for you based on finite differencing? If the latter, just use -snes_mf or -snes_mf_operator.<br><br>https://petsc.org/release/manual/snes/#jacobian-evaluation<br><br>Yi Hu <y.hu@mpie.de> writes:<br><br><blockquote type="cite">Dear PETSc team,<br><br>My solution scheme relies on a matrix-free jacobian in the SNES solver. I saw the useful C interface like MatCreateSNESMF(), DMSNESCreateJacobianMF(). I am wondering if you have the fortran equivalence?<br></blockquote></blockquote><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"> You can use DMSNESCreateJacobianMF() (MatCreateSNESMF is not appropriate when you are providing the operation).</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><blockquote type="cite" style="font-family: Helvetica; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><blockquote type="cite"><br>I think for my problem in the main program I need to do DMDASNESsetJacobianLocal(DM, INSERT_VALUES, myJacobian, ctx, err_petsc). Then in myJacobian() subroutine I have to create the operator from DMSNESCreateJacobianMF(), and register my own MATOP_MULT from MatShellSetOperation(). Am I correct?<br></blockquote></blockquote><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;">Not exactly. Do not use DMDASNESsetJacobianLocal() use DMSNESCreateJacobianMF() to create a Mat J where you create the SNES and use SNESSetJacobian() and pass the J matrix in along with myJacobian().</span><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; 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;"><blockquote type="cite" style="font-family: Helvetica; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><blockquote type="cite"><br>Are these fortran subroutines available? I saw an example in ts module<span class="Apple-converted-space"> </span><br>as ex22f_mf.F90 which behaves similar as what I would like to do. Because I would like to use ngmres, I then need to stay in the SNES.<br><br>Thanks for your help.<br><br>Best wishes,<br>Yi<br><br>-------------------------------------------------<br>Stay up to date and follow us on LinkedIn, Twitter and YouTube.<br><br>Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Straße 1<br>D-40237 Düsseldorf<br><br>Handelsregister B 2533<br>Amtsgericht Düsseldorf<br><br>Geschäftsführung<br>Prof. Dr. Gerhard Dehm<br>Prof. Dr. Jörg Neugebauer<br>Prof. Dr. Dierk Raabe<br>Dr. Kai de Weldige<br><br>Ust.-Id.-Nr.: DE 11 93 58 514<br>Steuernummer: 105 5891 1000<br><br><br>Please consider that invitations and e-mails of our institute are only<span class="Apple-converted-space"> </span><br>valid if they end with …@mpie.de.<br>If you are not sure of the validity please contact rco@mpie.de<br><br>Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails<span class="Apple-converted-space"> </span><br>aus unserem Haus nur mit der Endung …@mpie.de gültig sind.<br>In Zweifelsfällen wenden Sie sich bitte an rco@mpie.de<br>-------------------------------------------------<br></blockquote><br><br>-------------------------------------------------<br>Stay up to date and follow us on LinkedIn, Twitter and YouTube.<br><br>Max-Planck-Institut für Eisenforschung GmbH<br>Max-Planck-Straße 1<br>D-40237 Düsseldorf<br><br>Handelsregister B 2533<span class="Apple-converted-space"> </span><br>Amtsgericht Düsseldorf<br><br>Geschäftsführung<br>Prof. Dr. Gerhard Dehm<br>Prof. Dr. Jörg Neugebauer<br>Prof. Dr. Dierk Raabe<br>Dr. Kai de Weldige<br><br>Ust.-Id.-Nr.: DE 11 93 58 514<span class="Apple-converted-space"> </span><br>Steuernummer: 105 5891 1000<br><br><br>Please consider that invitations and e-mails of our institute are<span class="Apple-converted-space"> </span><br>only valid if they end with …@mpie.de.<span class="Apple-converted-space"> </span><br>If you are not sure of the validity please contact rco@mpie.de<br><br>Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails<br>aus unserem Haus nur mit der Endung …@mpie.de gültig sind.<span class="Apple-converted-space"> </span><br>In Zweifelsfällen wenden Sie sich bitte an rco@mpie.de<br>-------------------------------------------------</blockquote></div></blockquote></div><br></div></body></html>