<div dir="ltr"><div>Hi John,<br><br></div>This is great! Is there a way to pass this rule through the CBC CLI for use in relaxations?<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 25, 2015 at 3:23 PM, John Forrest <span dir="ltr"><<a href="mailto:john.forrest@fastercoin.com" target="_blank">john.forrest@fastercoin.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">At the last INFORMS I learnt about a very interesting idea on pivot selection for degenerate problems. Using donated code, this is now in Clp trunk. The idea is to do a bit more work to identify which variables are likely to lead to a degenerate move and avoid them.<br>
<br>
I would be grateful if you can give me feedback - or the authors who so generously contributed the code which I tinkered with.<br>
<br>
The easiest way to use the stand-alone version of Clp to test if this helps your problem is to add<br>
<br>
-psi 0.5 (for example) - 1.0 has no effect , 0.1 has much more.<br>
<br>
If you do<br>
<br>
clp<br>
psi??<br>
<br>
you will get a bit more information.<br>
<br>
The references are -<br>
<br>
Towhidi, M., Desrosiers, J., Soumis, F., 2014. The positive edge criterion within COIN-OR’s CLP. Computers & Operations Research 49, 41–46.<br>
Omer, J., Towhidi, M., Soumis, F., 2015. The positive edge pricing rule for the dual simplex. Computers & Operations Research, <a href="http://dx.doi.org/10.1016/j.cor.2015.03.009" rel="noreferrer" target="_blank">http://dx.doi.org/10.1016/j.cor.2015.03.009</a><br>
<br>
<br>
Enjoy<span class="HOEnZb"><font color="#888888"><br>
<br>
John Forrest<br>
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</font></span></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr">Matthew Gidden, Ph.D.<br>Postdoctoral Associate, Nuclear Engineering<div>The University of Wisconsin -- Madison<br>Ph. 225.892.3192<br></div></div></div></div></div>
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