<font face="arial,helvetica,sans-serif"></font>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">
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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
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<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 class="h5"><br>
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<br>
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<td>please help</td>
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<td>Wed, 03 Oct 2012 13:13:03 +0300</td>
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<td>Christos <a href="mailto:chtsolak@gmail.com" target="_blank"><chtsolak@gmail.com></a></td>
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<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>
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<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>
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<br>
</div></div></div>
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<br></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>