<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> What code are you running? So we can run a reproducer.<div><br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Aug 26, 2025, at 4:21 AM, Aldo Bonfiglioli <aldo.bonfiglioli@unibas.it> wrote:</div><br class="Apple-interchange-newline"><div>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div><p>Hi there,</p><p>I am using -ts_type pseudo to find steady solutions of the
Euler/NS PDEs.</p><p>It looks like FormRHSFunction is called twice with the exactly
same value of the dependent variable (u)</p><p>before invoking TSRHSJacobianFn and then solving the linear
system with KSP (u is then updated)<br>
</p><div>
<br class="webkit-block-placeholder"></div><blockquote type="cite"><span style="font-family:monospace"><span style="background-color: rgb(255, 255, 255);">1 TS dt
0.141197 time 0.141197</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
FormRHSFunction; ||u|| = 60.489405479528003
463.15635675129079 62.813532026019146
5.9789502719351155 </span><span style="background-color: rgb(255, 255, 255);"> </span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
FormRHSFunction; ||u|| = 60.489405479528003
463.15635675129079</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">62.813532026019146</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">5.9789502719351155</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
TSRHSJacobianFn with ||u|| = 60.489405479528003
463.15635675129079 62.813532026019146
5.9789502719351155</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);">
Linear solve converged due to CONVERGED_RTOL iterations
9</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
FormRHSFunction; ||u|| = 60.489405476878737</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">463.15635675602186</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">62.813532031616965</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">5.9789502710519811</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);">2 TS dt
0.155917 time 0.297115</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
FormRHSFunction; ||u|| = 60.489405476878737</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">463.15635675602186</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">62.813532031616965</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">5.9789502710519811</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
FormRHSFunction; ||u|| = 60.489405476878737</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">463.15635675602186</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">62.813532031616965</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">5.9789502710519811</span><span style="background-color: rgb(255, 255, 255);">
</span><br>
<span style="background-color: rgb(255, 255, 255);"> Calling
TSRHSJacobianFn with ||u|| = 60.489405476878737</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">463.15635675602186</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">62.813532031616965</span><span style="background-color: rgb(255, 255, 255);"> </span><span style="background-color: rgb(255, 255, 255);">5.9789502710519811</span><br>
<span style="background-color: rgb(255, 255, 255);">
</span><br>
</span></blockquote>
Why is it so? Am I possibly misusing (or missing) some options? <br><div><br class="webkit-block-placeholder"></div><p>My .petscrc file is attached.</p><p>Thank you,</p><p>Aldo<br>
</p>
<pre class="moz-signature" cols="72">--
Dr. Aldo Bonfiglioli
Associate professor of Fluid Mechanics
Dipartimento di Ingegneria
Universita' della Basilicata
V.le dell'Ateneo Lucano, 10 85100 Potenza ITALY
tel:+39.0971.205203 fax:+39.0971.205215
web: <a class="moz-txt-link-freetext" href="https://urldefense.us/v3/__http://docenti.unibas.it/site/home/docente.html?m=002423__;!!G_uCfscf7eWS!ci_aySHdF2Qx_B-37IOzELFDtcQRthJ2NItK-JNbfXB0M2_21B_z97WIfjxZUyKCVRRhd1mzL6b-rnCed_i8LLA56JvFdz7JBrw$">http://docenti.unibas.it/site/home/docente.html?m=002423</a></pre>
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<span id="cid:5804AA16-9971-495B-9920-B3405A020891"><dotpetscrc.txt></span></div></blockquote></div><br></div></body></html>