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Hi Lan,<br>
<br>
but in the Binpacking example, everything works as expected. Both
constraints added by ryanfoster-branching are inactive at first,
because they are added to the child nodes. They are only activated
when their nodes become active. <br>
<br>
<ol>
<li>Did you accidentally create your constraints with the "local"
flag set to FALSE?</li>
<li>Can you trace back when the constraint gets activated? You can
do this by printing a nice debug message from within the
SCIP_DECL_CONSACTIVE-callback of your constraint handler.<br>
</li>
</ol>
<br>
Best,<br>
Gregor<br>
<br>
<div class="moz-cite-prefix">Am 10.10.19 um 12:21 schrieb Ngô Lan:<br>
</div>
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<p>Hi Gregor,</p>
<p><br>
</p>
<p>Yeah the second question is about the main scip. So I saved
all the branching constraint to probdata after adding to main
scip and later in subscip, going through the vector of
branching constraints, checking which one is active using
SCIPconsIsActive and getting the dual of those that are
active. The issue here is that when I branch to 2 child nodes
and enter the first child node, it says the the constraint for
the other child node is also active in this node. I just
followed what you did in binpacking example: create cons, <span
style="font-family: Calibri, Helvetica, sans-serif,
EmojiFont, "Apple Color Emoji", "Segoe UI
Emoji", NotoColorEmoji, "Segoe UI Symbol",
"Android Emoji", EmojiSymbols; font-size: 16px;">
create child, </span>and add cons to child node. I think it
is pretty clear so that is why I don't really have any ideas
what can go wrong here. Any help is appreciated.</p>
<p><br>
</p>
<p>Thank you for your time.</p>
<p><br>
</p>
<p>Best,</p>
<p>Lan </p>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b> Gregor
Hendel <a class="moz-txt-link-rfc2396E" href="mailto:hendel@zib.de"><hendel@zib.de></a><br>
<b>Sent:</b> 10 October 2019 09:47:38<br>
<b>To:</b> Ngô Lan; <a class="moz-txt-link-abbreviated" href="mailto:Scip@zib.de">Scip@zib.de</a><br>
<b>Subject:</b> Re: [SCIP] Using SCIPdisableCons in problem
creation stage</font>
<div> </div>
</div>
<div>Hello Lan,<br>
<br>
find the answers to your two questions inline.<br>
<br>
<div class="moz-cite-prefix">Am 10.10.19 um 01:40 schrieb Ngô
Lan:<br>
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cite="mid:fa2f98ba0ff44cf6a513f4b3d6621037@aalto.fi">
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<p>Hi Gregor,</p>
<p><br>
</p>
<p>Thank you for your reply. It works now. Would it be
possible to add the deleted constraints again to scip?
Ideally, when a node is entered again, I would like to
enable the constraint instead of creating a new one. My
code does not run yet so I haven't had chance to test it.</p>
</div>
</blockquote>
As long as you do not release the constraint pointers (using
SCIPreleaseCons()), SCIP will not physically delete the
constraint, but only remove it from the problem, so that you can
later add them again. An explanation of the capture/release
mechanism for variables can be found here <a
class="moz-txt-link-freetext"
href="https://scip.zib.de/doc/html/OBJ.php"
moz-do-not-send="true">
https://scip.zib.de/doc/html/OBJ.php</a>, the explanation also
applies to constraints.<br>
<blockquote type="cite"
cite="mid:fa2f98ba0ff44cf6a513f4b3d6621037@aalto.fi">
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<p> </p>
<p><br>
</p>
<p>I also have another problem with the child nodes. So for
branching, I created a linear branching constraint and a
marker constraint from my constraints handler and added
them into a child node (sticking at node is true).
However, in subscip when I check in which branch I am at
using <span>SCIPconsIsActive, I get true even for the
constraints that were not created in this node. Do you
have any idea where things might go wrong?</span></p>
</div>
</blockquote>
As far as I understand your approach, all constraints of the
subscip should be active, because at every node (of the main
solving process), you free the transformed problem of the
subscip and then you add exactly those constraints that reflect
your current branching decision. Are you using SCIPconsIsActive
on the main solving process constraints, or on the subscip
constraints? For the main SCIP, I expect that all branching
constraints (there might be several ones along the path from the
root) are active, and the rest is not active.<br>
<br>
Kind regards,<br>
Gregor<br>
<br>
<blockquote type="cite"
cite="mid:fa2f98ba0ff44cf6a513f4b3d6621037@aalto.fi">
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style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;"
dir="ltr">
<p><span><br>
</span></p>
<p><span>Best,</span></p>
<p><span>Lan</span></p>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Scip
<a class="moz-txt-link-rfc2396E"
href="mailto:scip-bounces@zib.de" moz-do-not-send="true"><scip-bounces@zib.de></a>
on behalf of Gregor Hendel
<a class="moz-txt-link-rfc2396E"
href="mailto:hendel@zib.de" moz-do-not-send="true"><hendel@zib.de></a><br>
<b>Sent:</b> 09 October 2019 10:32:17<br>
<b>To:</b> <a class="moz-txt-link-abbreviated"
href="mailto:scip@zib.de" moz-do-not-send="true">scip@zib.de</a><br>
<b>Subject:</b> Re: [SCIP] Using SCIPdisableCons in
problem creation stage</font>
<div> </div>
</div>
<div>Good morning Lan,<br>
<br>
how about using SCIPdelCons() instead of SCIPdisableCons()?<br>
<br>
Let me know if that works for you,<br>
Gregor<br>
<br>
<div class="moz-cite-prefix">Am 09.10.19 um 01:03 schrieb
Ngô Lan:<br>
</div>
<blockquote type="cite"
cite="mid:0976bd261e9e485ca86dc452ba46b70a@aalto.fi">
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Helvetica, sans-serif, EmojiFont, "Apple Color
Emoji", "Segoe UI Emoji", NotoColorEmoji,
"Segoe UI Symbol", "Android Emoji",
EmojiSymbols;">
<p>Hi all,</p>
<p><br>
</p>
<p>I am solving a project scheduling problem using
branch-price-cut and I am having an issue with <span>SCIPdisableCons
function. So after each pricing iteration, I will
not release the subscip but only free the
transformed problem using SCIPfreetransform and
modify the objective function of the subscip in the
next iteration. During branching, in CONSACTIVE, I
will create an additional constraint for the
subproblem depending on the branching decision and
in CONSDEACTIVE, I will disable the related
constraint using <span>SCIPdisableCons. However, I
got the error: <span>cannot call method
<SCIPdisableCons> in problem creation
stage. Do you know another function that can
work? Or what should I do differently?</span></span></span></p>
<p><span><span><span><br>
</span></span></span></p>
<p><span><span><span>Thank you for your time,</span></span></span></p>
<p><br>
</p>
<p>Best,</p>
<p>Lan</p>
</div>
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