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<div class="moz-cite-prefix">Dear Vladimir V. Voloshinov,<br>
<br>
On 14.03.25 16:36, Vladimir V. Voloshinov wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAH87Kps3Ub++HiW2xrTrGPnJ2pbG9GZW4LfH3f9erh+R3naSiw@mail.gmail.com">
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<div>Dear SCIP team,</div>
<div><span style="white-space:pre-wrap">we</span><span
style="white-space:pre-wrap"> have been </span><span
style="white-space:pre-wrap">successfully</span><span
style="white-space:pre-wrap"> </span><span
style="white-space:pre-wrap">using</span><span
style="white-space:pre-wrap"> </span><span
style="white-space:pre-wrap">SCIP & FiberSCIP & ParaSCIP</span><span
style="white-space:pre-wrap"> for a </span><span
style="white-space:pre-wrap">long</span><span
style="white-space:pre-wrap"> </span><span
style="white-space:pre-wrap">time</span><span
style="white-space:pre-wrap">.</span></div>
<div><span style="white-space:pre-wrap">But sometimes some problems arise...
</span></div>
<div>Recently we found that FiberSCIP works very very slowly
in deterministic mode.</div>
<div><span style="white-space:pre-wrap">Moreover, it looks like <b><i>Deterministic=TRUE</i></b> (in ug.set file) switches off multithreading and regardless of <b><i>-sth</i></b> setting total CPU load becomes the same as for the case <b><i>-sth=1</i></b>.</span></div>
<div>But performance becomes even worse than for one
threaded SCIP... See example below.</div>
<div><br>
</div>
<div>The question is: maybe there are some other ways to get
a deterministic behaviour of FiberSCIP keeping
performance? The question arose when we tried to compare
FiberSCIP performance and results on different computing
environments...</div>
</div>
</div>
</div>
</blockquote>
<br>
No, unfortunately. The deterministic mode was developed only to
debug FiberSCIP more efficiently. <br>
Please read the FiberSCIP paper: <br>
<a class="moz-txt-link-freetext" href="https://pubsonline.informs.org/doi/10.1287/ijoc.2017.0762">https://pubsonline.informs.org/doi/10.1287/ijoc.2017.0762</a><br>
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{page:WordSection1;}</style>And, it would not always be deterministic
with the current version of SCIP.<br>
<br>
Best regards,<br>
Yuji<br>
<br>
<blockquote type="cite"
cite="mid:CAH87Kps3Ub++HiW2xrTrGPnJ2pbG9GZW4LfH3f9erh+R3naSiw@mail.gmail.com">
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<div><br>
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<div>Below is an example of results for some NLP global
optimization problem without discrete variables but with
SOS2 constraints:</div>
<div><span style="font-family:arial,sans-serif">___________________________________________________________</span></div>
<div><span style="font-family:arial,sans-serif">Presolved
Problem :<br>
Variables : 145 (0 binary, 0 integer, 0 implicit
integer, 145 continuous)<br>
Constraints : 61<br>
Constraints : Number<br>
SOS2 : 15 <br>
linear : 30 <br>
nonlinear : 16 <br>
</span></div>
<div>--------------------------------------------------------------------------------------------------</div>
<div>It was solved with total 10% gap, <b><i>-sth=16</i></b>
and <b><i>Deterministic=FALSE</i></b> in 87 sec:</div>
<div>
<div><span style="font-family:arial,sans-serif">_____________________________________________________</span></div>
SCIP Status : solving was interrupted [given gap
reached]<br>
Total Time : 86.80<br>
</div>
<div>B&B Tree : nodes (total) : 202112<br>
Solution :<br>
Primal Bound : +3.10185241045302e-03<br>
Dual Bound : +2.98514588645749e-03<br>
Gap : 3.90958 %</div>
<div>----------------------------------------------------------------------------------------</div>
<div><br>
</div>
<div>But solving time with the same settings and <i><b>Deterministic=TRUE</b></i>
became almost 50 times bigger:</div>
<div><span style="font-family:arial,sans-serif">_____________________________________________________</span></div>
<div>
<div>SCIP Status : solving was interrupted [given
gap reached]<br>
Total Time : 4216.07<br>
B&B Tree : nodes (total) : 141474<br>
Solution :<br>
Primal Bound : +3.09812857597093e-03<br>
Dual Bound : +2.98180690970866e-03<br>
Gap : 3.90105 %<br>
----------------------------------------------------------------------------------------</div>
<div><br>
</div>
Sincerely yours,</div>
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<div>Vladimir V. Voloshinov,<br>
web: <a
href="https://scholar.google.ru/citations?hl=en&user=-m4QhNEAAAAJ&view_op=list_works&sortby=pubdate"
target="_blank" moz-do-not-send="true">GoogleScholar
profile</a></div>
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<pre wrap="" class="moz-quote-pre">_______________________________________________
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<a class="moz-txt-link-freetext" href="https://listserv.zib.de/mailman/listinfo/scip">https://listserv.zib.de/mailman/listinfo/scip</a>
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</blockquote>
<br>
<br>
<pre class="moz-signature" cols="0">--
--------------------------------------------------
Yuji Shinano
Zuse Institute Berlin
Takustrasse 7, 14195 Berlin-Dahlem, Germany
Phone:+49 30 84185-477, Fax:+49 30 84185-269</pre>
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