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Dear Stuart,<br>
<br>
thanks for sharing your results!<br>
<br>
When modifying a central component like the LP solver it is often
unpredictable what might change with regard to SCIP's performance.
There are a few differences between the two interfaces (e.g.
persistent scaling), although they run exactly the same solver under
the hood. Maybe you could send me some details (problem instances,
settings, log files) about your findings so that I can have a closer
look.<br>
<br>
I would also like to address your previous question concerning CLP
and SoPlex.<br>
<br>
While CLP is a very efficient and advanced LP solver as demonstrated
in the Mittelmann benchmarks, it's important to keep in mind that
this is comparing pure LP performance. SoPlex is lacking some
presolving techniques to get a better performance there. Within SCIP
though, you can see that SoPlex is performing a lot better and is
even quite close to the speed of SCIP using CPLEX.<br>
There is simply a lot of performance variability involved when
dealing with such complex codes and my suggestion to you would be to
try different settings or solvers from time to time - and please let
us know when SCIP/SoPlex is especially under- or over-performing :-)<br>
<br>
Happy SCIPing!<br>
Matthias<br>
<br>
<br>
<div class="moz-cite-prefix">On 02-Dec-17 23:58, Stuart Rogers
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAGd4rrHhp7ZmD7H0b3KUBosqObbdcLORcUvYYYOH_QQow6DvwQ@mail.gmail.com">
<div dir="ltr">I use SCIP through GAMS, for which soplex2 or
soplex can be used as the LP solver: <a
href="https://www.gams.com/latest/docs/S_SCIP.html#SCIP_OPTIONS"
moz-do-not-send="true">https://www.gams.com/latest/docs/S_SCIP.html#SCIP_OPTIONS</a>.
For GAMS SCIP, I believe soplex2 calls the new interface spx,
while soplex calls the older interface spx1. In my tests solving
a MINLP with GAMS SCIP, I find that SCIP converges more rapidly
when using soplex (which uses the older interface) compared to
soplex2 (which uses the newer interface). Can you explain this?
Thanks, Stuart</div>
<br>
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<pre class="moz-signature" cols="72">--
\__________________
Matthias Miltenberger
Zuse Institute Berlin
Takustr. 7, 14195 Berlin
<a class="moz-txt-link-abbreviated" href="http://www.zib.de/miltenberger">www.zib.de/miltenberger</a>
<a class="moz-txt-link-abbreviated" href="mailto:miltenberger@zib.de">miltenberger@zib.de</a>
+49 (30) 841 85 245 </pre>
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