<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Dear Bahareh,<br>
<br>
do you also add the constraint via SCIPaddCons() or (better in your
case) SCIPaddConsNode()?<br>
<br>
Best,<br>
Gerald<br>
<br>
<div class="moz-cite-prefix">Am 30.03.2015 um 07:48 schrieb Bahareh
Eghtesadi:<br>
</div>
<blockquote
cite="mid:CA+t7RjFzC8cxEBkdC-KMN2PK36DE3-NUm5o=hDjSDS-=cCzNdA@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>
<div>
<div>Hi Gerald,<br>
<br>
</div>
Thanks for your explanation. I now understand how these
constraints work. So they are not basically added to the
subproblems causing additional constraints(which I was
trying to avoid).<br>
</div>
So I am now creating two child nodes using SCIPcreatechild,
then create the constraint of the conshdlr and add them to
the node by SCIPaddconsnode. <br>
</div>
After one iteration, when one constraint is added to a
node,and the prop is done , it goes in the pricing(to see if
any cons is active and if so change bounds), but
SCIPconshdlrGetConss(conshdlr) returns no constraint! I have
checked the conshdlr is found by SCIPfindConshdlr, and it is
the one attached to the node. Is there a way to check if the
constraint is being created? because the SCIPcreatecon seems
to be working fine, and I have no other idea why it can
happen.<br>
</div>
<div>I would appreciate your suggestions.<br>
<br>
</div>
<div>Thanks.<br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Mar 19, 2015 at 8:00 AM, Gerald
Gamrath <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:gamrath@zib.de" target="_blank">gamrath@zib.de</a>></span>
wrote:<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 Bahareh,<br>
<br>
you say that you store corresponding bounds and other
information in the consdata and use the CONSACTIVE method
to apply them in the pricer data. Both of this uses a (set
of) constraints, not just the constraint handler. Of
course, within the constraint handler, you define how the
data of a single constraint should look like and what
should be done if the constraint is activated. So I don't
really get your question, you are already using
constraints...<br>
<br>
I don't see how you could have the information about bound
changes for each node other than by storing them in
constraints sticked to nodes. You might store all this in
the constraint handler data, but you would then need to
keep track of all created nodes and store a "copy" of the
tree there, which is not convenient.<br>
Also the CONSACTIVE callback is not called if no
constraint is activated...<br>
<br>
So I think there is no easy way to do this without
creating constraints.<br>
<br>
Best,<br>
Gerald
<div>
<div class="h5"><br>
<br>
<div>Am 18.03.2015 um 19:02 schrieb Bahareh Eghtesadi:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi <span
style="font-size:12.8000001907349px">Stephen,</span>
<div><span style="font-size:12.8000001907349px"><br>
</span></div>
<div><span style="font-size:12.8000001907349px">Thank
you for your response. </span></div>
<div><span style="font-size:12.8000001907349px">Actually
I have been looking at the Bin Packing
example. Here is what I have done so far: In
my branching rule, I choose which pricing
variable to branch on, create two nodes and
store the corresponding bounds and other
information in the consdata for each node. In
the conshdlr, </span><span
style="font-size:12.8000001907349px"> </span><span
style="font-size:12.8000001907349px">in
CONSACTIVE method, </span><span
style="font-size:12.8000001907349px">I change
the bounds stored in the pricer data. </span></div>
<div>Do I still have to create the constraint of <span
style="font-size:12.8000001907349px">constraint
handler in each node? Because I do not have
any constraint in fact, I am using the handlr
to apply changes to my pricer data(bounds). I
set the NEEDSCONS flag to False, and was
hoping that it would be enough.</span></div>
<div>Also, in this case I would not need to check
whether the "cons" is active in my variable
pricer. Is this right?</div>
<div>I appreciate your help. This is my first
experience with SCIP, and I am afraid I have
oversimplified everything.</div>
<div><br>
</div>
<div><br>
</div>
<div>Thanks. </div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Mar 18, 2015 at
8:42 AM, Stephen J Maher <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:maher@zib.de" target="_blank">maher@zib.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">Hi Bahareh,<br>
<br>
Branching on original variables can be
performed similar to the way used for
branching on constraints, i.e. Ryan-Foster
branching.<br>
<br>
In order to implement this type of branching
you will need to write your own constraint
handler, branching rule and modify the
variable pricer. The constraint handler will
take some reference to the original variable
and selected bounds as input and determine
which master problem variables satisfy this
constraint based on given variable bounds. In
your branching rule, you will decide what
original variable to branch on, create two
branching nodes and then add a constraint of
your constraint handler to each with
appropriate bounds. In your variable pricer,
it is then necessary to check whether any
constraints of this type exist at the current
node and apply the appropriate variable bounds
on the original variables.<br>
<br>
An example of Ryan-Foster branching is given
in the Bin Packing example included with SCIP.
It should be possible to use this as a guide
for your own rule branching on original
variables.<br>
<br>
Cheers,<br>
<br>
Stephen
<div>
<div><br>
<br>
On 13/03/15 07:14, Bahareh Eghtesadi
wrote:<br>
</div>
</div>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div>
<div> Hi all,<br>
<br>
I am tying to implement a branch and
price algorithm. I want to branch<br>
on the original variables that are not
present in the master problem,<br>
and then change their bound in the
pricing problems. But I am not sure<br>
how to do this. I think I can't use
SCIPbranchvar directly from<br>
mybranchrule. If I use a constraint
handler, I wouldn't make a<br>
constraint of that type (because there
is no such constraint), then how<br>
can I include it in my branchrule?<br>
<br>
<br>
Thanks in advance.<br>
<br>
<br>
</div>
</div>
_______________________________________________<br>
Scip mailing list<br>
<a moz-do-not-send="true"
href="mailto:Scip@zib.de" target="_blank">Scip@zib.de</a><br>
<a moz-do-not-send="true"
href="http://listserv.zib.de/mailman/listinfo/scip"
target="_blank">http://listserv.zib.de/mailman/listinfo/scip</a><br>
<br>
</blockquote>
_______________________________________________<br>
Scip mailing list<br>
<a moz-do-not-send="true"
href="mailto:Scip@zib.de" target="_blank">Scip@zib.de</a><br>
<a moz-do-not-send="true"
href="http://listserv.zib.de/mailman/listinfo/scip"
target="_blank">http://listserv.zib.de/mailman/listinfo/scip</a><br>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div><span
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">Regards</span><br
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">
<span
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">Bahareh
Eghtesadi</span><br>
</div>
</div>
<br>
<fieldset></fieldset>
<br>
<pre>_______________________________________________
Scip mailing list
<a moz-do-not-send="true" href="mailto:Scip@zib.de" target="_blank">Scip@zib.de</a>
<a moz-do-not-send="true" href="http://listserv.zib.de/mailman/listinfo/scip" target="_blank">http://listserv.zib.de/mailman/listinfo/scip</a>
</pre>
</blockquote>
<br>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
<div class="gmail_signature"><span
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">Regards</span><br
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">
<span
style="background-color:rgb(255,255,255);color:rgb(153,153,153)">Bahareh
Eghtesadi</span><br>
</div>
</div>
</blockquote>
<br>
</body>
</html>