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<div class="moz-cite-prefix">Yves,<br>
<br>
The intended use for cutlength was just for efficiency not for
accuracy. However your problems seem to pose more problems on
accuracy because you have general integer variables, continuous
variables and many <= or >= rows. The computations in
CglGomory allow for the slight relaxation of a cut rhs when there
are more variables in cut, BUT it did not look at the extra work
done for >= rows at bound - this can lead to cancellation due
to very small values, so the number of variables in cut does not
totally reflect the possible inaccuracy. Well .... anyway
something like that.<br>
<br>
I have updated CglGomory to try and reflect this. It does not
seem to do any harm in my tests, so I am checking the change into
trunk. If anyone notices significant degradation in their work,
then tell me and go back to previous way by defining
CGL_GOMORY_OLD_RELAX in your configure.<br>
<br>
John Forrest<br>
<br>
<br>
<br>
On 03/12/14 17:59, Yves Touchard wrote:<br>
</div>
<blockquote cite="mid:547F4F9E.2070406@dxo.com" type="cite">
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charset=windows-1252">
<font size="-1">Hello,<br>
<br>
<font size="-1"><font size="-1">There is a constraint file <font
size="-1">(<a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="https://www.dropbox.com/s/e1x1xilj4gr200u/timing1.lp?dl=0">https://www.dropbox.com/s/e1x1xilj4gr200u/timing1.lp?dl=0</a>)
which is not solved when cutl<font size="-1">ength is 40<font
size="-1">:</font></font></font></font></font><br>
<br>
<i>bin/cbc timing1.lp threads 104 ratio 0.05 cutlength 40
multiple 4 dives 301 branch printingOptions rows solution
timing1.sol</i><br>
<br>
<font size="-1">but has an optimal solution if cut<font
size="-1">length is 30:<br>
<br>
</font></font></font><i><font size="-1">bin/cbc timing1.lp
threads 104 ratio 0.05 cutlength
<font size="-1">3</font>0 multiple 4 dives 301 branch
printingOptions rows solution timing1.sol</font></i><br>
<br>
<small>Not sure to know which value is fine for my set of
problems.</small><br>
<br>
<small>Regards<br>
<br>
Yves<br>
<br>
[Tests done with Rev #2100 and #2099 of Cbc trunk]<br>
</small><br>
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