Sorry for the delay. Since this problem is an LP and does get pre-processed by SYMPHONY, it is simply passed through to the LP solver, which is Clp by default. This must be a bug in Clp. It seems to be related to some bugs reported on other mailing lists. I will check into it. I suppose it should be a simple fix.<br>
<br>Cheers,<br><br>Ted<br><br><div class="gmail_quote">On Thu, Jul 19, 2012 at 4:46 PM, Federico Larumbe <span dir="ltr"><<a href="mailto:federico.larumbe@polymtl.ca" target="_blank">federico.larumbe@polymtl.ca</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,
<div><br></div><div>I am testing Symphony with a simple example in AMPL format:</div><div><div><font face="'courier new', monospace"><br></font></div><div><font face="'courier new', monospace"><div>symphony -F file.mod -D file.dat</div>
</font></div><div><font face="'courier new', monospace"><br></font></div></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><span style="font-family:'courier new',monospace">-- file.mod ------</span><span style="font-family:'courier new',monospace">------------</span></div>
</div><div><div><font face="'courier new', monospace">var y >= 0;</font></div></div><div><div><font face="'courier new', monospace"><br></font></div></div><div><div><font face="'courier new', monospace">minimize ObjectiveFunction: y;</font></div>
</div><div><div><font face="'courier new', monospace"><br></font></div></div><div><div><font face="'courier new', monospace">subject to C1: y >= 1.0;</font></div></div><div><div><font face="'courier new', monospace">subject to C2: y <= 2.0;</font></div>
</div><div><div><font face="'courier new', monospace">subject to C3: y = 1.1;</font></div></div><div><div><font face="'courier new', monospace"><br></font></div></div><div><div><font face="'courier new', monospace">end;</font></div>
</div><div><span style="font-family:'courier new',monospace">------------------</span><span style="font-family:'courier new',monospace">------------</span></div><div><span style="font-family:'courier new',monospace"><br>
</span></div><div><div><span style="font-family:'courier new',monospace">-- file.dat ------</span><span style="font-family:'courier new',monospace">------------</span></div></div><div><span style="font-family:'courier new',monospace">data;</span></div>
<div><span style="font-family:'courier new',monospace">end;</span></div><div><div><span style="font-family:'courier new',monospace">------------------</span><span style="font-family:'courier new',monospace">------------</span></div>
</div></blockquote><div><span style="font-family:'courier new',monospace"><br></span></div><div><font face="arial, helvetica, sans-serif">The solution given by the program is 2.0 instead of 1.1 (see attached file). If I choose maximize, the solution is 1.0. If I remove C3, the problem is unbounded. Is there any option that I missing?</font></div>
<div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">I compiled Sympthony in SUSE Linux with gcc 4.5.1 with the following commands:</font></div><div><font face="arial, helvetica, sans-serif"><br>
</font></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><font face="'courier new', monospace">./configure --with-gmpl --enable-openm</font></div><div><font face="'courier new', monospace">make</font></div>
</blockquote><div><font face="arial, helvetica, sans-serif"><br></font></div><div><font face="arial, helvetica, sans-serif">Thanks a lot,</font></div><div><font face="arial, helvetica, sans-serif">Federico.</font></div><span class="HOEnZb"><font color="#888888"><div>
<br></div>-- <br>Federico Larumbe<br>École Polytechnique de Montréal<br>Montréal H3C 3A9<br><br>Group for Research in Decision Analysis (GERAD)<br>tel <a href="tel:%2B1%20514%203406053%20xt%206931" value="+15143406053" target="_blank">+1 514 3406053 xt 6931</a><br>
fax <a href="tel:%2B1%20514%203405665" value="+15143405665" target="_blank">+1 514 3405665</a><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Dr. Ted Ralphs<br>Associate Professor, Lehigh University<br>(610) 628-1280<br>ted 'at' lehigh 'dot' edu<br><a href="http://coral.ie.lehigh.edu/%7Eted" target="_blank">coral.ie.lehigh.edu/~ted</a><br>
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