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Dear Matheus,<br>
<br>
if you create your constraints as linear constraints, and not as
rows, you cannot add them with SCIPaddRowProbing, but should rather
use SCIPaddConsNode and provide the probing node as the node to add
the constraint to.<br>
<br>
I would recommend to have a look at the multi-aggregated branching
rule (src/scip/branch_multaggr.c), which does something very similar
to what you want to do.<br>
<br>
Best,<br>
Gerald<br>
<br>
<div class="moz-cite-prefix">On 21.03.2018 00:26, Matheus Ota wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAL0UnZ09oFiSgnAVC2E2Wy_i1-Td=MZrrPh8NeJYRVaqvNZORQ@mail.gmail.com">
<div dir="ltr">
<div>Hi,<br>
<br>
</div>
<div>Thanks for the fast reply! I followed what you said, but I
guess I'm doing something wrong, can you help me to figure it
out?<br>
<br>
</div>
<div>So first I enclosed the part of the code that I want to
compute the lower bounds in SCIPstartProbing(scip) and
SCIPendProbing(scip).<br>
<br>
</div>
<div>Then I call SCIPnewProbingNode(scip), create the
constraint1 and add it with SCIPaddRowProbing(scip,
constraint1). I then solve the probing node with
SCIPsolveProbingLP(scip, -1, &lperror, &cutoff), get
the lower bound with SCIPgetLPObjval(scip) and got back to the
parent with SCIPbacktrackProbing(scip, 1).<br>
<br>
</div>
<div>This same process is then repeated imposing constraint2 in
the problem.<br>
<br>
</div>
<div>Can you tell me if this is the right way to do it? The code
is not working as it was before adding the branching rule and
I'm having some difficulties in understanding how to use the
probing mode correctly.<br>
<br>
</div>
<div>Thanks again,<br>
</div>
<div>Matheus</div>
<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2018-03-20 5:52 GMT-03:00 Gregor Hendel
<span dir="ltr"><<a href="mailto:hendel@zib.de"
target="_blank" moz-do-not-send="true">hendel@zib.de</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Dear Matheus,<br>
<br>
this sounds like an application of the SCIP probing mode,
which allows to explore some tentative children before
branching. Please have a look at the documentation of the
probing mode:<br>
<br>
<a class="m_3923750445048037240moz-txt-link-freetext"
href="http://scip.zib.de/doc-5.0.1/html/group__PublicProbingMethods.php"
target="_blank" moz-do-not-send="true">http://scip.zib.de/doc-5.0.1/<wbr>html/group__<wbr>PublicProbingMethods.php</a><br>
<br>
Probing mode supports local constraints at the tentative
node, and solve the corresponding LP relaxation.<br>
<br>
You can then retrieve the LP solution objective using
SCIPgetLPObjval(), see also<br>
<br>
<a class="m_3923750445048037240moz-txt-link-freetext"
href="http://scip.zib.de/doc-5.0.1/html/group__PublicLPMethods.php"
target="_blank" moz-do-not-send="true">http://scip.zib.de/doc-5.0.1/<wbr>html/group__PublicLPMethods.<wbr>php</a><br>
<br>
for further information.<br>
<br>
Happy probing,<br>
Gregor
<div>
<div class="h5"><br>
<br>
<br>
<div class="m_3923750445048037240moz-cite-prefix">Am
19.03.2018 um 21:45 schrieb Matheus Ota:<br>
</div>
</div>
</div>
<blockquote type="cite">
<div>
<div class="h5">
<div dir="ltr">
<div>
<div>
<div>Hi,<br>
<br>
</div>
Im trying to use SCIP to implement a
Branch-Cut-and-Price for the VRP. For now Im
focusing only on the Branch-and-Cut part,
using the CVRPSEP package (<a
href="http://econ.au.dk/research/researcher-websites/jens-lysgaard/cvrpsep/"
target="_blank" moz-do-not-send="true">http://econ.au.dk/research/<wbr>researcher-websites/jens-<wbr>lysgaard/cvrpsep/</a>).
I already added the cuts and my program is
able to solve some simple instances, in order
to increase its performance I need to
implement custom branching rules. <br>
<br>
</div>
The branching rule works this way: it first
select a few subsets of the set of vertexes in
the graph and impose a few constraints on them.
It then computes the lower bound (solving the
relaxation) for each child node and uses these
values to choose the node to branch on. Could
you please give me some information about of how
I can get the lower bound on the branching rule
callback? Or maybe a better way of doing this or
something similar?<br>
<br>
</div>
<div>Thanks,<br>
</div>
<div>Matheus <br>
</div>
</div>
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