<div dir="ltr">Matteo<div><br></div><div>eventually (and in some sense counterintuitively) the DM stores the information on the problem, not SNES. See the snippet below to make things more clear</div><div><br></div><div>SNESSetDM(snes1,dm)</div><div>SNESSetFunction(snes1,F)</div><div>SNESSolve(snes1) // Solves F(x)=0 <div><br></div><div>SNESSetDM(snes2,dm)</div><div>SNESSetFunction(snes2,G)</div><div>SNESSolve(snes2) // Solves G(x)=0 <div><br></div></div><div>SNESSolve(snes1) // Solves G(x), not F(x)!!</div><div><br></div><div>If you have a plex you can call DMClone(dm,dm2) and set a new section on dm2 to be used on snes2 (the mesh won't be duplicated, only the problem dependent part)</div><div>I guess you can follow the same approach with a DMDA, it should work. If not, you may need to call DMDuplicate on the DMDA.</div><div><br></div><div><br></div></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">Il giorno gio 6 nov 2025 alle ore 11:19 Matteo Semplice via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</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"><u></u>
<div>
<p>Dear Barry,</p>
<p> sorry for jumping into this.</p>
<p><br>
</p>
<p>I am wondering if your reply is related to DMDA or to DM in
general. I have at least one code where I do something similar to
what Samuele did in his sample code: create a DMPlex, create a
section on this DMPlex, create two SNES solving for Vecs defined
on that same section and attach to each of them a different
SNESFunction and SNESJacobian (one solves a predictor and the
other is a corrector). Everything seems fine, but I am wondering
if that code is somewhat weak and should be changed by DMCloning
the plex as you suggested to Samuele.</p>
<p><br>
</p>
<p>Thanks</p>
<p> Matteo</p>
<p><br>
</p>
<div>On 06/11/2025 07:49, Samuele Ferri
wrote:<br>
</div>
<blockquote type="cite">
<table border="0" cellspacing="0" cellpadding="0" width="100%" style="background:revert;color:revert;direction:revert;font-size:revert;height:revert;letter-spacing:revert;line-height:revert;margin:revert;opacity:revert;outline:revert;overflow:revert;padding:revert;text-align:revert;text-indent:revert;text-orientation:revert;text-overflow:revert;text-transform:revert;vertical-align:revert;white-space:revert;word-break:revert;word-spacing:revert;writing-mode:revert;zoom:revert;border:0px;display:table;width:100%;table-layout:fixed;float:none;border-spacing:0px" align="left">
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<td valign="middle" width="100%" bgcolor="#EAEAEA" cellpadding="7px 5px 7px 15px" color="#212121" style="background-image:revert;background-position:revert;background-size:revert;background-repeat:revert;background-origin:revert;background-clip:revert;border:revert;direction:revert;display:revert;height:revert;letter-spacing:revert;line-height:revert;margin:revert;opacity:revert;outline:revert;overflow:revert;table-layout:revert;text-indent:revert;text-orientation:revert;text-overflow:revert;text-transform:revert;vertical-align:revert;white-space:revert;word-break:revert;word-spacing:revert;writing-mode:revert;zoom:revert;width:100%;background-color:rgb(234,234,234);padding:7px 5px 7px 15px;font-family:wf_segoe-ui_normal,"Segoe UI","Segoe WP",Tahoma,Arial,sans-serif;font-size:12px;font-weight:normal;color:rgb(33,33,33);text-align:left">
<div style="background:revert;border:revert;color:revert;direction:revert;display:revert;font-size:revert;height:revert;letter-spacing:revert;line-height:revert;margin:revert;opacity:revert;outline:revert;overflow:revert;padding:revert;table-layout:revert;text-align:revert;text-indent:revert;text-orientation:revert;text-overflow:revert;text-transform:revert;vertical-align:revert;white-space:revert;width:revert;word-break:revert;word-spacing:revert;writing-mode:revert;zoom:revert">
<a href="mailto:sale987@live.com" target="_blank">sale987@live.com</a> sembra simile a un utente che in
precedenza ti ha inviato un messaggio di posta
elettronica, ma potrebbe non essere lo stesso.
<a href="https://urldefense.us/v3/__https://aka.ms/LearnAboutSenderIdentification__;!!G_uCfscf7eWS!d2x1h3Pt9OqhfeBcqW8pR0dbGy3bRw6bM-p0DxGAaY0CXWkqH3lpsuXiob9mOqfsy-aRVJXUig3819n2CWpYyFn4FDaTAWRxNDXZsA$" style="background:revert;color:revert;direction:revert;display:revert;font-size:revert;opacity:revert" target="_blank">
Scopri perché potrebbe trattarsi di un rischio</a> </div>
</td>
<td valign="middle" align="left" width="75px" bgcolor="#EAEAEA" cellpadding="7px 5px 7px 5px" color="#212121" style="background-image:revert;background-position:revert;background-size:revert;background-repeat:revert;background-origin:revert;background-clip:revert;border:revert;direction:revert;display:revert;height:revert;letter-spacing:revert;line-height:revert;margin:revert;opacity:revert;outline:revert;overflow:revert;table-layout:revert;text-indent:revert;text-orientation:revert;text-overflow:revert;text-transform:revert;vertical-align:revert;white-space:revert;word-break:revert;word-spacing:revert;writing-mode:revert;zoom:revert;width:75px;background-color:rgb(234,234,234);padding:7px 5px;font-family:wf_segoe-ui_normal,"Segoe UI","Segoe WP",Tahoma,Arial,sans-serif;font-size:12px;font-weight:normal;color:rgb(33,33,33);text-align:left"><br>
</td>
</tr>
</tbody>
</table>
<div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Dear Barry,</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
thank you for your reply. Now everything works fine.</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Best regards</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Samuele</div>
<hr style="display:inline-block;width:98%">
<div id="m_-685146062800039339divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>Da:</b> Barry Smith
<a href="mailto:bsmith@petsc.dev" target="_blank"><bsmith@petsc.dev></a><br>
<b>Inviato:</b> mercoledì 5 novembre 2025 15:47<br>
<b>A:</b> Samuele Ferri <a href="mailto:sale987@live.com" target="_blank"><sale987@live.com></a><br>
<b>Cc:</b> <a href="mailto:petsc-users@mcs.anl.gov" target="_blank">petsc-users@mcs.anl.gov</a>
<a href="mailto:petsc-users@mcs.anl.gov" target="_blank"><petsc-users@mcs.anl.gov></a><br>
<b>Oggetto:</b> Re: [petsc-users] Two SNES on the same DM
not working</font>
<div> </div>
</div>
<div>
<div><br>
</div>
This is not supported. Duplicate your DM.<br id="m_-685146062800039339x_lineBreakAtBeginningOfMessage">
<div><br>
<blockquote type="cite">
<div>On Nov 5, 2025, at 9:17 AM, Samuele Ferri
<a href="mailto:sale987@live.com" target="_blank"><sale987@live.com></a> wrote:</div>
<br>
<div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
Dear petsc users,</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
in petsc version 3.24, I'm trying to create two snes
over the same DM, but with different functions and
jacobians. Despite making different calls to
SNESSetFunction it happens the second snes uses the
same function of the first.</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
Can you help me finding the problem, please?</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
Here below there is a minimal working example showing
the issue:</div>
<div 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;text-decoration:none;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div style="font-family:Helvetica;font-size:18px;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;text-decoration:none">
<div style="line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
static char help[] = "Test SNES.\n";</div>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
#include <petscsys.h></div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
#include <petscdmda.h></div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
#include <petscsnes.h><br>
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscErrorCode Jac_1(SNES<span> </span><i>snes</i>,
Vec<span> </span><i>x</i>,
Mat<span> </span><i>J</i>,
Mat<span> </span><i>B</i>,
void *){</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionBegin;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("Jac 1\n");</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionReturn(PETSC_SUCCESS);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
}</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscErrorCode Function_1(SNES<span> </span><i>snes</i>,
Vec<span> </span><i>x</i>,
Vec<span> </span><i>f</i>,
void *){</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionBegin;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("Function 1\n");</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionReturn(PETSC_SUCCESS);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
}</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscErrorCode Jac_2(SNES<span> </span><i>snes</i>,
Vec<span> </span><i>x</i>,
Mat<span> </span><i>J</i>,
Mat<span> </span><i>B</i>,
void *){</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionBegin;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("Jac 2\n");</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionReturn(PETSC_SUCCESS);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
}</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscErrorCode Function_2(SNES<span> </span><i>snes</i>,
Vec<span> </span><i>x</i>,
Vec<span> </span><i>f</i>,
void *){</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionBegin;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("Function 2\n");</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionReturn(PETSC_SUCCESS);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
}<br>
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
int main(int<span> </span><i>argc</i>,
char **<i>argv</i>) {</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionBeginUser;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(PetscInitialize(&<i>argc</i>, &<i>argv</i>,
NULL, help));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
DM dm;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMDACreate1d(PETSC_COMM_WORLD,
DM_BOUNDARY_NONE, 100, 1, 1, NULL, &dm));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMSetFromOptions(dm));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMSetUp(dm));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
SNES snes1, snes2;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
Vec r1,r2;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
Mat J1, J2;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMCreateGlobalVector(dm, &r1));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMCreateGlobalVector(dm, &r2))</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMCreateMatrix(dm, &J1));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(DMCreateMatrix(dm, &J2));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESCreate(PETSC_COMM_WORLD,
&snes1));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESCreate(PETSC_COMM_WORLD,
&snes2));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetType(snes1, SNESNEWTONLS));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetType(snes2, SNESNEWTONLS));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetFromOptions(snes1));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetFromOptions(snes2));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetFunction(snes1, r1, Function_1,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetFunction(snes2, r2, Function_2,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetJacobian(snes1, J1, J1, Jac_1,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetJacobian(snes2, J2, J2, Jac_2,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetDM(snes1, dm));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSetDM(snes2, dm));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSolve(snes1, NULL, NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESSolve(snes2, NULL, NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("snes1 %p; snes2 %p\n", snes1, snes2);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
<br>
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
SNESFunctionFn *p;</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESGetFunction(snes1, NULL, &p,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("snes1: pointer %p, true function %p\n",
*p, Function_1);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(SNESGetFunction(snes2, NULL, &p,
NULL));</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
printf("snes2: pointer %p, true function %p\n",
*p, Function_2);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscCall(PetscFinalize());</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
PetscFunctionReturn(PETSC_SUCCESS);</div>
<div 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;text-decoration:none;line-height:22px;font-family:Calibri,Helvetica,sans-serif;font-size:12pt">
}</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<pre cols="72">--
Prof. Matteo Semplice
Università degli Studi dell’Insubria
Dipartimento di Scienza e Alta Tecnologia – DiSAT
Professore Associato
Via Valleggio, 11 – 22100 Como (CO) – Italia
tel.: +39 031 2386316</pre>
</div>
</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature">Stefano</div>