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Dear James,<br>
<br>
if you only want to branch on this particular variable, it shouldn't
be necessary to get all branching candidates. You could write a
branching rule where you just check the bounds of your particular
variable (you can get it via SCIPfindVar()), in case they are equal,
you return SCIP_DIDNOTRUN to skip your branching rule and continue
with SCIP's own ones. Otherwise you directly call SCIPbranchVar() to
branch on your variable. <br>
<br>
If you wanted to use the SCIPgetPseudoBranchCands() callback (which,
as I said, shouldn't be necessary), you would get a list of all
possible candidates to iterate over and select one based on any
criterion of your choice. In your case, you could iterate over the
list and check whether any of the variables is named "x".<br>
<br>
Best,<br>
Tristan<br>
<br>
<div class="moz-cite-prefix">On 02/16/2017 04:13 PM, James Cussens
wrote:<br>
</div>
<blockquote
cite="mid:CALQgqO2SyUxCR+-JQ_vtm-N2Ea8Ys5DJfkqR9o-r5uUm_CCpuA@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Dear SCIPers,</div>
<div><br>
</div>
I have a problem which includes a particular integer variable
(call it x) which I always want to branch on even if it is
integral and other binary/integer variables are fractional - I
would only branch on any other variable if x were fixed. As for
how to branch on this variable, the BRANCHEXECPS approach
described here:
<div><a moz-do-not-send="true"
href="http://scip.zib.de/doc/html/BRANCH.php">http://scip.zib.de/doc/html/BRANCH.php</a></div>
<div>is exactly what I am looking for.<br>
<div><br>
</div>
<div>Giving this x variable maximal branching priority does
not work, since if (as is normally the case) there is an LP
solution with some fractional variables not including my x,
then x will not be branched on.</div>
<div><br>
</div>
<div>So it looks like I need to write my own (simple)
branching rule where the BRANCHEXECLP callback grabs
branching candidates using SCIPgetPseudoBranchCands rather
than SCIPgetLPBranchCands. However, looking at the code in
branch.c it appears that SCIPgetPseudoBranchCands returns
branching candidates without taking variable priority into
account.</div>
<div><br>
</div>
<div>Is that correct?</div>
<div><br>
</div>
<div>Best wishes,</div>
<div><br>
</div>
<div>James<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature">James Cussens<br>
Dept of Computer Science &<br>
York Centre for Complex Systems Analysis<br>
Room 326, The Hub, Deramore Lane Tel +44
(0)1904 325371<br>
University of York
Fax +44 (0)1904 500159<br>
York YO10 5GE, UK <a
moz-do-not-send="true"
href="http://www.cs.york.ac.uk/%7Ejc" target="_blank">http://www.cs.york.ac.uk/~jc</a><br>
<a moz-do-not-send="true"
href="http://www.york.ac.uk/docs/disclaimer/email.htm"
target="_blank">http://www.york.ac.uk/docs/disclaimer/email.htm</a></div>
</div>
</div>
</div>
<br>
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<br>
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</blockquote>
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