<font face="arial,helvetica,sans-serif">Some options may accelerate (or slowdown) a lot. Heuristics usually have a huge impact on the solution time. Try including<br><br>cbc air04.mps.gz passF 100 solve<br><br>Also, if you to not need the optimality proof you can disable cuts<br>
</font><br><font face="arial,helvetica,sans-serif"><font face="arial,helvetica,sans-serif">cbc air04.mps.gz passF 100 </font></font><font face="arial,helvetica,sans-serif"><font face="arial,helvetica,sans-serif"><font face="arial,helvetica,sans-serif">cuts off</font> solve</font><br>
<br>[]'s<br></font><br><div class="gmail_quote">On Fri, Oct 5, 2012 at 5:20 AM, Christos <span dir="ltr"><<a href="mailto:chtsolak@gmail.com" target="_blank">chtsolak@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Thank you for your suggestion, i will
check it and let you know. <br>
<br>
But i think the problem is elsewhere.<br>
When i solve the same problem with gams via cbc solver it takes
30-60 seconds, and not 60 minutes! <br>
Why?<div><div class="h5"><br>
<br>
On 4/10/2012 17:57, Haroldo Santos wrote:<br>
</div></div></div><div><div class="h5">
<blockquote type="cite">On Thu, Oct 4, 2012 at 6:41 AM, Christos <span dir="ltr"><<a href="mailto:chtsolak@gmail.com" target="_blank">chtsolak@gmail.com</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> I am asking you because
i have a big problem. With very small alteration in data
operation time goes from 9' to 65' !!!<br>
</div>
</blockquote>
<div>This is expected when solving Integer Programs if you are
willing to proof the optimality.<br>
One thing you can do to exit more quickly, if you do not need
the optimal solution (a good one may be enough), is to force
the solver to quit after finding some solutions with the
maxSolutions paramater.<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> <br>
Any recommendations on the way i solve the model? <br>
Do you think that the above times are normal for such a
model?
<div>
<div><br>
<div><br>
<br>
-------- Original Message --------
<table border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<th align="RIGHT" nowrap valign="BASELINE">Subject: </th>
<td>please help</td>
</tr>
<tr>
<th align="RIGHT" nowrap valign="BASELINE">Date: </th>
<td>Wed, 03 Oct 2012 13:13:03 +0300</td>
</tr>
<tr>
<th align="RIGHT" nowrap valign="BASELINE">From: </th>
<td>Christos <a href="mailto:chtsolak@gmail.com" target="_blank"><chtsolak@gmail.com></a></td>
</tr>
<tr>
<th align="RIGHT" nowrap valign="BASELINE">To: </th>
<td><a href="mailto:cbc@list.coin-or.org" target="_blank">cbc@list.coin-or.org</a> <a href="mailto:cbc@list.coin-or.org" target="_blank"><cbc@list.coin-or.org></a></td>
</tr>
</tbody>
</table>
<br>
<br>
Hi all,<br>
<br>
i am a student in the final phase of the Milp model
which i want to solve.<br>
<br>
So, i have a milp model<br>
columns: 46614<br>
integers: 12540 (binary)<br>
rows: 40842<br>
nonzeros:117823<br>
<br>
I tried these simple methods <br>
1.<br>
<i><small>solver1.loadProblem(numcols, numrows, start,
index, value, collb, colub, obj, rowlb, rowub);<br>
solver1.initialSolve();<br>
solver1.branchAndBound() ;</small></i><br>
2.<br>
<i><small>solver1.loadProblem(numcols, numrows, start,
index, value, collb, colub, obj, rowlb, rowub);<br>
CbcModel model(solver1);<br>
CbcMain0(model);<br>
const char * argv2[]={"DAS","-solve","-quit"}; </small></i>->
<u>i don't know what this do.</u><i><small><br>
CbcMain1(3,argv2,model); <br>
<br>
</small></i><small><big>Since i am an amateur, can
you help me?<br>
What method should i use to solve the model? 1,2
or something else?<br>
Any recommendations?<br>
<br>
The 1st takes an hour and stops.<br>
The 2nd takes either 8' or 35' depending on the
data.<br>
<br>
Your help is much appreciated.<span><font color="#888888"><br>
<br>
Christos</font></span></big></small><br>
<br>
</div>
<br>
</div>
</div>
</div>
<br>
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</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
=============================================================<br>
Haroldo Gambini Santos<br>
Computing Department - Universidade Federal de Ouro Preto - UFOP<br>
email: haroldo [at ] <a href="http://iceb.ufop.br" target="_blank">iceb.ufop.br</a><br>
home/research page: <a href="http://www.decom.ufop.br/haroldo/" target="_blank">www.decom.ufop.br/haroldo/</a><br>
<br>
"Computer science is no more about computers than astronomy <br>
is about telescopes." Edsger Dijkstra<br>
<br>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br><br clear="all"><br>-- <br>=============================================================<br>Haroldo Gambini Santos<br>Computing Department - Universidade Federal de Ouro Preto - UFOP<br>email: haroldo [at ] <a href="http://iceb.ufop.br" target="_blank">iceb.ufop.br</a><br>
home/research page: <a href="http://www.decom.ufop.br/haroldo/" target="_blank">www.decom.ufop.br/haroldo/</a><br> <br>"Computer science is no more about computers than astronomy <br>is about telescopes." Edsger Dijkstra<br>
<br>