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<div class="moz-cite-prefix">Yves,<br>
<br>
Will look into it. Any change can (and does on your problems)
change the accuracy - maybe on cuts derived from original
constraints plus cuts. <br>
<br>
But you have it the wrong way round. cutlength XX says throw away
all cuts with length > XX. The smaller XX, the more cuts will
be thrown away and so accuracy will be no worse. As to efficiency
- it could go either way. GMI cuts seem to be more accurate and
Lagrangean Gomory cuts should be more accurate.<br>
<br>
So for production purposes I would set cutlength 20.<br>
<br>
John<br>
<br>
On 19/12/14 15:01, Yves Touchard wrote:<br>
</div>
<blockquote cite="mid:54943DC8.20901@dxo.com" type="cite">
<meta http-equiv="Context-Type" content="text/html;
charset=ISO-8859-1">
John,<br>
<br>
I am sorry to disturb you (once more) about the cutlength value.<br>
<br>
From my understanding, increasing this value
decreases efficiency and increases accuracy.<br>
And decreasing this value, increases efficiency and decreases
accuracy.<br>
<br>
So, if i am not wrong, please, could you explain me the following
behaviour:<br>
[ <i>bin/cbc t_18.lp threads 104 cutlength </i><i>XX</i><i>
divesolves 301 ratio 0</i><i>.05</i><i> multiple 4 branch
printingOptions rows solution t_18..sol</i> ]<br>
[ <i>t18_lp file is there: </i><i><a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="https://www.dropbox.com/s/748azg1miloa3iw/t_18.lp?dl=0">https://www.dropbox.com/s/748azg1miloa3iw/t_18.lp?dl=0</a></i>
]<br>
<ul>
<li>With a XX cutlength value of 5, 10, 15, 20, 25, 29, 31, 35
and 50 the optimal solution is found.
</li>
<li>With a XX cutlength value of 30 and 45, the problem
is infeasible (but become feasible with a multiple value of
1).
</li>
</ul>
Regards,<br>
<br>
Yves<br>
<br>
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