<br><font size=2 face="sans-serif">Joerg,</font>
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<br><font size=2 face="sans-serif">I have committed the change to CglProbing
to fix your problem.</font>
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<br><font size=2 face="sans-serif">John Forrest</font>
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<td width=40%><font size=1 face="sans-serif"><b>"Joerg Herbers"
<Joerg.Herbers@inform-ac.com></b> </font>
<br><font size=1 face="sans-serif">Sent by: coin-discuss-bounces@list.coin-or.org</font>
<p><font size=1 face="sans-serif">06/07/2006 05:36 PM</font>
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<div align=center><font size=1 face="sans-serif">Please respond to<br>
Discussions about open source software for Operations Research
<coin-discuss@list.coin-or.org></font></div></table>
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<div align=right><font size=1 face="sans-serif">To</font></div>
<td><font size=1 face="sans-serif"><coin-discuss@list.coin-or.org></font>
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<div align=right><font size=1 face="sans-serif">cc</font></div>
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<div align=right><font size=1 face="sans-serif">Subject</font></div>
<td><font size=1 face="sans-serif">[Coin-discuss] Probing problem</font></table>
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<br><tt><font size=2>I've got problems using CglProbing in preprocessing
(via CglPreProcess) on an IP formulation with general integer variables.<br>
<br>
In the formulation, a variable has lb=1 and ub=DBL_MAX. Since solval=1
in CglProbing.cpp (l. 2424), the "down" and "up" variables
are set to 1.0 and 2.0, respectively (l. 2432-2435). Consequently, "movement"
is set to 1.0-DBL_MAX (l. 2462). When the first alternative is tested in
probing (l. 2497), colUpper is set to colUpper-movement=DBL_MAX+(1.0-DBL_MAX).
This should give 1.0 - but it actually results in 0.0, leading to infeasibility
and incorrect results of probing.<br>
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Is there a general recommendation of not using DBL_MAX as a marker for
an open upper bound? Or could we make CglProbing "DBL_MAX-safe"?<br>
<br>
Thanks in advance,<br>
Joerg<br>
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-- <br>
<br>
Dr. Jörg Herbers<br>
Airport Systems Division<br>
INFORM GmbH, Pascalstraße 23, 52076 Aachen, Germany<br>
Telefon: (+49) 2408 9456-24, Fax: (+49) 2408 9456-25<br>
E-Mail: joerg.herbers@inform-ac.com, Web: http://www.inform-ac.com <br>
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