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Dear Ahmed,<br>
<br>
during presolving SCIP tries to replace bilinear terms containing
binary variables. E.g., one can linearize the product of a bounded
continuous and a binary variable, or replacing products of binary
variables by using an AND constraint.<br>
<br>
This happens in the presolveTryAddLinearReform() function in the
quadratic constraint handler:
<a class="moz-txt-link-freetext" href="http://scip.zib.de/doc/html_devel/cons__quadratic_8c.php#a8d01446423ab326dd8fe6a2f088de671">http://scip.zib.de/doc/html_devel/cons__quadratic_8c.php#a8d01446423ab326dd8fe6a2f088de671</a><br>
<br>
Now, to reformulate those products SCIP uses auxiliary constraints
and for those you can specify with the <u>binreforminitial </u>parameter
if the LP relaxations of those constraints should be in the initial
LP.<br>
<br>
When linearizing those bilinear products you might introduce very
large coefficients on the binary variables in the auxiliary
constraints. To avoid those big-M constraints SCIP checks if the
absolute value of the coefficient of the binary variable is larger
than (1/feasibility tolerance) * binreformmaxcoef.<br>
<br>
Hope this helps!<br>
<br>
<br>
Best,<br>
<br>
Benny<br>
<br>
<div class="moz-cite-prefix">On 26.12.2015 23:32, Ahmed Ibrahim
wrote:<br>
</div>
<blockquote
cite="mid:7BE9AA462EB7354CAA5256EB22A6A0DCB8ADF669@UMCE3EXMD01.ad.umanitoba.ca"
type="cite">
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<div style="direction: ltr;font-family: Tahoma;color:
#000000;font-size: 10pt;">Hi SCIP community,
<div>I was wondering if someone can provide a precise
explanation of the following parameters in quadratic
constraint handler:</div>
<div>
<ol>
<li><u>constraints/quadratic/binreformmaxcoef</u> </li>
<li><u>constraints/quadratic/binreforminitial</u></li>
</ol>
I've read the brief explanation for these two parameters in
<a class="moz-txt-link-rfc2396E" href="http://scip.zib.de/doc/html/PARAMETERS.php">"http://scip.zib.de/doc/html/PARAMETERS.php"</a><a
moz-do-not-send="true"
href="http://scip.zib.de/doc/html/PARAMETERS.php"
target="_blank" style="font-size: 10pt;">http://scip.zib.de/doc/html/PARAMETERS.php</a> however
the explanation didn't seem completely clear for me. </div>
<div><br>
</div>
<div>Regards,</div>
<div>Ahmed</div>
</div>
<br>
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<br>
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