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<p>Hi Gregor,</p>
<p><br>
</p>
<p>For my problem, in each child node, I would add 2 constraints (1 linear and 1 from my own constraint handler as a marker constraint). When printing out in <span style="color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">SCIP_DECL_CONSACTIVE,
the right marker constraint is activated. For the linear constraint, I did create it as local constraint, save it in a vector in probdata and check it in my pricer but here when I used SCIPconsIsLocal, it returned False. I used also SCIPconsIsLocal directly
after I created the linear constraint but here I got True. Is there something SCIP does internally that affects the local attribute?</span></p>
<p><span style="color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;"><br>
</span></p>
<p><span style="color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">Best,</span></p>
<p><span style="color: rgb(33, 33, 33); font-family: wf_segoe-ui_normal, "Segoe UI", "Segoe WP", Tahoma, Arial, sans-serif, serif, EmojiFont; font-size: 15px;">Lan</span></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Gregor Hendel <hendel@zib.de><br>
<b>Sent:</b> 11 October 2019 15:26:51<br>
<b>To:</b> Ngô Lan<br>
<b>Cc:</b> scip@zib.de<br>
<b>Subject:</b> Re: [SCIP] Using SCIPdisableCons in problem creation stage</font>
<div> </div>
</div>
<div>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>
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<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>
</div>
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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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<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"><style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
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12pt; color: rgb(0, 0, 0); font-family: Calibri,
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>
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