<div dir="ltr"><div dir="ltr"><div>Hello,</div><div><br></div><div>In the past I solved the same issue.</div><div>As Stephane points out, try to play with ODEOPTIONS.</div><div>In my case (disretized PDE), I get massive speed up by setting<pre style="font-family:Monospaced;font-style:normal"><span style="color:rgb(0,0,0)">%ODEOPTIONS</span><span style="color:rgb(74,85,219)">(</span><span style="color:rgb(188,143,143)">6</span><span style="color:rgb(74,85,219)">)</span> <span style="color:rgb(92,92,92)">=</span> <span style="color:rgb(188,143,143)">0</span></pre></div><div><div><div class="gmail_signature" data-smartmail="gmail_signature">and selecting a stiff solver.</div><div class="gmail_signature" data-smartmail="gmail_signature"><br></div><div class="gmail_signature" data-smartmail="gmail_signature">If I understand it correctly, you are using function interp1 when evaluating ODE function (many calls to interp1).<br></div><div class="gmail_signature" data-smartmail="gmail_signature">If it is this case, I propose to make a copy of Scilab interp1 function and clean unecessary commands.</div><div class="gmail_signature" data-smartmail="gmail_signature">I have also good experience with this aproach, but you are loosing flexibility and is a ad hoc function.<br></div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><br>Best regards</div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><br></div><div class="gmail_signature" data-smartmail="gmail_signature">J.K.</div><div class="gmail_signature" data-smartmail="gmail_signature"><br></div><div class="gmail_signature" data-smartmail="gmail_signature">PS: it is great to hear that ODE solvers will be updated to more recent versions.<br></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">št 2. 9. 2021 o 18:32 Stéphane Mottelet <<a href="mailto:stephane.mottelet@utc.fr">stephane.mottelet@utc.fr</a>> napísal(a):<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<div>Le 02/09/2021 à 18:03, CHEZE David
227480 a écrit :<br>
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<p class="MsoNormal">Dear all,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><span lang="EN-GB">In experimental work,
I’m comparing dynamic model of a thermal system with
measurements. I’m using function ode, “fix” solver
(continuous time, lowest accuracy requirement is applying in
my case at this stage) and Jacobian ( to try to speed up the
calculation but not sensitive as for now) to get the
solution of the equation, a single temperature node, at 240
times (time vector), default rtol=1.d-3 and atol=1.d-4. The
system inputs are available as vector of reals , size is 240
and inputs are passed to the ode function as inputs
functions by interpolating (interp1) the inputs vectors. It
is issuing correct temperature solutions but is very slow,
~40s for 240 times, while the variable inputs vector are
actually not varying a lot and thus I would expect very
short calculation time. <u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-GB">WIN10-64bits Intel i7
2,6GHz, Scilab 6.1.1<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-GB">Is there any tips to
speed up the calculation , advanced example documentation
about ODEOPTIONS or ode_optional_output ? I guess it’s the
same underlying code that is used in Xcos isn’t it ?</span></p>
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No. Xcos uses the (more up-to-date) SUNDIALS solvers, they will be
made available at the user level in the next months.
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<p class="MsoNormal"><span lang="EN-GB"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-GB">Thank you for advising,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial",sans-serif" lang="EN-GB"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:10pt;font-family:"Arial",sans-serif">David
</span><span><u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
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<pre cols="72">--
Stéphane Mottelet
Ingénieur de recherche
EA 4297 Transformations Intégrées de la Matière Renouvelable
Département Génie des Procédés Industriels
Sorbonne Universités - Université de Technologie de Compiègne
CS 60319, 60203 Compiègne cedex
Tel : +33(0)344234688
<a href="http://www.utc.fr/~mottelet" target="_blank">http://www.utc.fr/~mottelet</a>
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