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<div class="moz-cite-prefix">Hi Diego,<br>
<br>
did you implement the CONSCHECK callback of your constraint
handler and does it correctly check that the summation of the
variables is integral? If not, SCIP will check the root initial LP
solution for feasibility and if your constraint handler does not
complain, this solution will be accepted, such that the problem is
already solved before branching could be invoked.<br>
<br>
Best,<br>
Gerald<br>
<br>
On 10.03.2016 11:28, <a class="moz-txt-link-abbreviated" href="mailto:dponce@us.es">dponce@us.es</a> wrote:<br>
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<p>Hello Gerald,</p>
<p>thank you for your answer. After some work I have more
questions.</p>
<p>I have removed the branching rule pluging and now it is
substitued by the enfolp callback within the contraint handler
pluging. However, <strong>the enfolp is never invoqued</strong>.</p>
<p>I would like to remark that in my problem I have defined <strong>ALL
the variables as continuous</strong> (there is no binary nor
integer variable) since the only discrete entity that we have
are that the sumation of some of these variables are 0-1.
Neverthelees I do not want to define artificial variables as the
sum of pairs.</p>
<p>I've read next thread of questions and asnwers about some
similar situation (enfolp seemed to be not invoqued) but it is
not clear how her problem was solved.</p>
<p><a moz-do-not-send="true"
href="http://listserv.zib.de/pipermail/scip/2013-April/001433.html">http://listserv.zib.de/pipermail/scip/2013-April/001433.html</a></p>
<p>1. Having the problem as a pure LP (with all continuous
variables), will the constraint handler be invoqued?</p>
<p>2. I have thought that I could add some dummy binary variables
independent from the problem that will be forzed to branch only
at the end (by means of the appropriate priority of my
constraint handler) at the very end of each branching of the
tree, but it seems too ARTIFICIAL. Can the branching be done in
a neater way?</p>
<p>3. Am I missing something?</p>
<p><br>
To put the right information, the properties of the constraint
handler in my implementation are set to:</p>
<div> </div>
<p>#define CONSHDLR_ENFOPRIORITY 99999 <br>
#define CONSHDLR_CHECKPRIORITY -1 <br>
#define CONSHDLR_EAGERFREQ 1 <br>
#define CONSHDLR_NEEDSCONS FALSE</p>
<p>Best.</p>
<p>Diego.</p>
<p>El 07/03/2016 11:26, Gerald Gamrath escribió:</p>
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<div class="moz-cite-prefix">Hi Diego,<br>
<br>
branching is done as part of the enforcement of LP (or pseudo)
solutions. The enforcement callback of the integrality
constraint handler calls the branching rules by decreasing
priority. But any other constraint handler with active
constraints can also do branching.<br>
<br>
Thus, you can implement your own constraint handler which
checks whether you need to do branching in the CONSENFOLP
callback. You should add one constraint of this handler which
stores the data needed to check feasibility.<br>
<br>
Note that the enforcement callbacks of constraint handler are
called in decreasing priority until one did perform a
branching. So you could even mix branching on integer
variables with other branching by your own constraint handler.
If your constraint handler has a positive priority, it will
always be called before the integer variable branching,
otherwise afterwards. In your case, however, I would recommend
to just define your variables as continuous.<br>
<br>
Best,<br>
Gerald<br>
<br>
On 04.03.2016 17:23, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated" href="mailto:dponce@us.es">dponce@us.es</a>
wrote:</div>
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#1010ff 2px solid; margin: 0">
<p>Hello list,</p>
<p>I have to develope a Ryan and Foster Branching similar to
the binpacking one. The difference is that when I finish my
branching I cannot assure integrality on the variables. But
I don't have to, since I'm able to build a solution for my
problem easily.</p>
<p>It is possible to force the problem to go to the branching
when I define my variables as continuous? If not, is there a
way to just use my branching and no the default branching?</p>
<p>Best.</p>
<p>Diego.</p>
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