<div dir="ltr">Hi Stefan,<div><br></div><div>Many thanks for the overview of options. I think for us, the last one (.osil files, and use the OS/Ipopt interface to run Ipopt) would be the feasible one, but writing a function that outputs the problem in that XML format is not something we can do right now. But it's good to know what we need to do if we want to go down that route!</div>
<div><br></div><div>Cheers,</div><div><br></div><div>Ramon.</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 23 June 2014 23:30, Stefan Vigerske <span dir="ltr"><<a href="mailto:stefan@math.hu-berlin.de" target="_blank">stefan@math.hu-berlin.de</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
no, you need AMPL to produce a file in .nl format.<br>
And AMPL needs AMPL .mod files as input, which SCIP cannot write either.<br>
<br>
You could let SCIP write your PIP as .gms file, and then use GAMS to convert it to a .mod file. Or you can Ipopt via GAMS.<br>
But all this requires a GAMS license.<br>
<br>
If you write your .pip files by some program anyway, then you could probably modify it to write .mod files, too. Then with AMPL you could convert these into .nl files.<br>
Or you could write .osil files, and use the OS/Ipopt interface to run Ipopt. That would be an all-open-source way to do it.<br>
<br>
Stefan<div><div class="h5"><br>
<br>
On 06/24/2014 12:20 AM, Ramón Casero Cañas wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
Dear all,<br>
<br>
Sorry for the sligh off-topic. I'd like to compare SCIP to ipopt solving a<br>
problem. I see that SCIP v 3.1.0 can save to formats<br>
<br>
file reader extension description<br>
----------- --------- -----------<br>
ccgreader ccg file writer for column connectivity graph<br>
file format<br>
cipreader cip file reader for CIP (Constraint Integer<br>
Program) format<br>
fznreader fzn file reader for FlatZinc format<br>
gmsreader gms file writer for MI(NL)(SOC)Ps in GAMS file<br>
format<br>
lpreader lp file reader for MIPs in IBM CPLEX's LP<br>
file format<br>
mpsreader mps file reader for MIQPs in IBM's<br>
Mathematical Programming System format<br>
opbreader opb file reader for pseudo-Boolean problem in<br>
opb format<br>
pipreader pip file reader for polynomial mixed-integer<br>
programs in PIP format<br>
ppmreader ppm file writer for portable pixmap file<br>
format (PPM), open with common graphic viewer programs (e.g. xview)<br>
pbmreader pbm file writer for portable bitmap file<br>
format (PBM), open with common graphic viewer programs (e.g. xview)<br>
rlpreader rlp file reader for MIPs in IBM CPLEX's RLP<br>
file format<br>
wboreader wbo file reader for pseudoboolean wbo file<br>
format<br>
<br>
but not to .nl, which is the format that the ipopt binary can load. Is<br>
there a way to produce an .nl file from the .pip file that I use to load<br>
the problem into SCIP?<br>
<br>
Best regards,<br>
<br>
Ramon.<br>
<br>
<br>
<br></div></div>
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</blockquote>
<br>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr">Dr. Ramón Casero Cañas<br><br>Institute of Biomedical Engineering<br>Department of Engineering Science, University of Oxford<br>Old Road Campus Research Building, Headington <br>
Oxford <br>OX3 7DQ<br>UK<br><br>tlf +44 (0) 1865 617716<br>twitter @Ramon_Casero<br>web <a href="http://www.cs.ox.ac.uk/people/Ramon.CaseroCanas/" target="_blank">http://www.cs.ox.ac.uk/people/Ramon.CaseroCanas/</a><br>
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