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Dear Xavier,<br>
<br>
you are absolutely right! I missed that you are only looping over
the LP branching candidates in the example, and as you said, this
ignores variables with value 1. So the bug was really in the example
code, sorry for the confusion.<br>
<br>
Do you have an instance where this can be reproduced (with the
example code)?<br>
<br>
I did a short fix that might be a bit easier than your fix, and also
made a few other things in the code somewhat easier. I will send it
to you in a separate mail, perhaps you can test that it works?<br>
<br>
Best,<br>
Gerald<br>
<br>
<div class="moz-cite-prefix">Am 24.03.2017 um 12:26 schrieb Xavier
Schepler:<br>
</div>
<blockquote
cite="mid:CA+SwSLw3Oi93RbLeH5qkwuaAT+Oqst+YY0JC1TiugOK18uFz9w@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>
<div>Dear Gerald,<br>
<br>
</div>
I tryed again and got the same error, after removing
my fix.<br>
</div>
It looks like there is really an error in the code of
the example, probably because the function
SCIPgetLPBranchCands return only fractional variables.<br>
<br>
</div>
What may happen is that a variable standing for a pair
may have a value equal to 1, so it won't be taken into
account when computing the sum, which will be between 0
and 1.<br>
<br>
</div>
</div>
What do you think ?<br>
<br>
</div>
Kind regards,<br>
<br>
</div>
Xavier<br>
<div>
<div>
<div>
<div><br>
<br>
</div>
</div>
</div>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2017-03-24 12:12 GMT+01:00 Xavier
Schepler <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:xavier.schepler@gmail.com" target="_blank">xavier.schepler@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>
<div>Dear Gerald,<br>
<br>
</div>
Ok, I get it, there is something wrong with my part
of the code :o)<br>
<br>
</div>
Thank you very much for your help !<br>
<br>
</div>
Kind regards,<br>
<br>
</div>
Xavier<br>
<div>
<div>
<div><br>
<br>
</div>
</div>
</div>
</div>
<div class="HOEnZb">
<div class="h5">
<div class="gmail_extra"><br>
<div class="gmail_quote">2017-03-24 12:00 GMT+01:00
Gerald Gamrath <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:gamrath@zib.de" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:gamrath@zib.de">gamrath@zib.de</a></a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<p>Dear Xavier,</p>
<p>I agree that this is confusing, but I guess
the example is doing the right thing. Because
after summing up the LP values for the pairs
of variables, you do not check this for
fractionality, but take</p>
<p><tt>value = MIN(pairweights[i][j],
1-pairweights[i][j]);</tt><tt><br>
</tt></p>
and compare this to the bestvalue which is
initialized to 0.0. So if the pairweight is
larger than 1, the min is always negative and
this variable will not be chosen as a branching
candidate. I'm not sure this case was taken into
account when writing this code, but it seems to
work anyway. :-)<br>
<br>
Best,<br>
Gerald
<div>
<div class="m_5442217572206144159h5"><br>
<br>
<br>
<div
class="m_5442217572206144159m_-2019721574131620711moz-cite-prefix">On
24.03.2017 09:45, Xavier Schepler wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>
<div>
<div>
<div>Dear Gerald,<br>
<br>
</div>
Yes, my problem has this property,
that each subset of a valid
packing is again a valid packing.
Each item must be covered once in
the end.<br>
<br>
</div>
You are totally right : I should
choose two items such that those are
together in some of the packings
selected by the LP solution and also
some packings are selected that
contain exactly one of the items.<br>
<br>
</div>
What looks like a bug to me is that in
the file branch_ryanfoster.c of the
bin-packing example, the only thing
that is checked to select the
branching candidate is that the sum
over the pair of items is fractional,
but it is not checked if at the same
time there is a packing that contains
exactly one of the items with a
fractional value.<br>
<br>
</div>
<div>There would be at least two ways to
correct that : check if a branching
was done before on the pair (what I
do), or check if at the same time
there is packing that contains exactly
one of the items with a fractional
value.</div>
<div><br>
</div>
<div>Kind regards,<br>
<br>
</div>
<div>Xavier Schepler<br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2017-03-23
23:00 GMT+01:00 Gerald Gamrath <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:gamrath@zib.de"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:gamrath@zib.de">gamrath@zib.de</a></a>></span>:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div bgcolor="#FFFFFF"
text="#000000"> Dear Xavier,<br>
<br>
but does your problem have the
property, that each subset of a
valid packing is again a valid
packing? And each item must be
covered once in the end?<br>
I would say that you can then
ignore pairs of variables for
which the sum over the LP values
is larger than 1, because you
could post-process this in the end
and reduce this value by removing
both items for some packings.<br>
More specifically, you should
choose two items such that those
are together in some of the
packings selected by the LP
solution and also some packings
are selected that contain exactly
one of the items. This is not the
case for your example. If you do
Ryan and Foster branching based in
this criterion, each variable
should have a value 0 or 1 in the
end.<br>
<br>
I hope this makes sense.<br>
<br>
Best,<br>
Gerald
<div>
<div
class="m_5442217572206144159m_-2019721574131620711h5"><br>
<br>
<br>
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338moz-cite-prefix">Am
23.03.2017 um 18:50 schrieb
Xavier Schepler:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>I meant :<br>
<br>
After re-optimization,
the sum over the
variables which cover
items 1 and 3 is still
fractional, and its
value is <b>1.5.</b>
(not 0.5)<br>
<br>
</div>
<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2017-03-23
18:45 GMT+01:00 Xavier
Schepler <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:xavier.schepler@gmail.com" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:xavier.schepler@gmail.com">xavier.schepler@gmail.com</a></a>></span>:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px
#ccc
solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>Dear
Gerald,<br>
<br>
</div>
Thank you for
your response.<br>
</div>
<br>
Assume that a
branching
constraint was
added, enforcing
that items 1 and 3
must be in the
same bin. The
variables that do
not satisfy this
constraint were
deleted. The
resulting LP is
the one in the
attached file.
After
re-optimization,
the sum over the
variables which
cover items 1 and
3 is still
fractional, and
its value is 0.5.
Assume that no
improving variable
is priced out,
during the column
generation phase.
What does prevent
the same branching
constraint to be
generated again ?<br>
</div>
<div>This is
because, in the
case of a set
covering problem,
the sum over the
variables which
cover items 1 and
3 can be greater
than one and
fractional, which
can not happen
with a set
partitionning
problem.<br>
</div>
<div>So, my opinion
is that, with the
set covering
formulation, in
the case of a
fractional sum
value for a pair
of a items, it
must be checked
whether the
branching
constraint is
satisfied (i.e.
that it is already
exists), and only
in the case that
is is not, to
create it.<br>
<br>
</div>
<div>Does it make
sense ?<br>
</div>
<div><br>
</div>
<div>Kind regards,<br>
</div>
<div><br>
</div>
<div>Xavier<br>
</div>
<br>
</div>
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338HOEnZb">
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338h5">
<div
class="gmail_extra"><br>
<div
class="gmail_quote">2017-03-23
16:38
GMT+01:00
Gerald Gamrath
<span
dir="ltr"><<a
moz-do-not-send="true"
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338moz-txt-link-abbreviated"
href="mailto:gamrath@zib.de" target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:gamrath@zib.de">gamrath@zib.de</a></a>></span>:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div
bgcolor="#FFFFFF"
text="#000000">
<p>Dear
Xavier,</p>
<p>I would
guess that
there is a bug
in your
pricing
problem.</p>
<p>Normally,
if you branch
on items i and
j and go into,
say, the child
node where
SAME(i,j)
should hold,
you fix all
packings
locally to 0,
which contain
exactly one of
the two items.
But
additionally,
you need to
adjust your
pricing
problem, so
that no
further
packings with
that property
are priced in
in this
subtree, say
by adding a
constraint x_i
= x_j. Note
that variables
are always
valid
globally, so
if you jump
through the
tree and come
back to this
sub-tree later
on, you need
to repropagate
the node again
to make sure
that variables
generated in
between also
stick to the
branching
decision.</p>
<p>This works
fine for set
partitioning
problems or
set covering
problems if
you can ensure
that there is
always at
least one
optimal
solution which
would be
feasible for
the
corresponding
set
partitioning
problem.</p>
<p>If in your
problem, this
is not the
case and there
is no optimal
solution which
fulfills all
constraints
with equality,
I fear you
cannot use
Ryan and
Foster
branching.</p>
<p>Your fix
might cure the
symptoms, but
I guess the
bug itself
persists.
Because if you
did some
branching on
SAME(i,j)
before, there
should not be
any incentive
to do the same
branching
again. If
there is, then
the old
branching was
actually not
strictly
enforced, and
as such, you
might now
choose to not
do the same
branching
again, but you
might end up
with a
situation
where you
performed all
possible
branching but
are still not
feasible,
since as it
seems, your
branchings are
not (always)
respected.</p>
Best,<br>
Gerald
<div>
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753h5"><br>
<br>
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958moz-cite-prefix">On
23.03.2017
16:09, Xavier
Schepler
wrote:<br>
</div>
</div>
</div>
<blockquote
type="cite">
<div>
<div
class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753h5">
<div dir="ltr">
<div>
<div>Dear SCIP
developers,<br>
<br>
</div>
I'm working on
a variant of
the
bin-packing
problem. I
started from
the example of
a
branch-and-price
algorithm for
the bin
packing
problem
provided with
SCIP 3.2.1. It
uses the Ryan
and Foster
branching
rule.<br>
<br>
</div>
<div>However,
the master
problem is a
set cover
problem, so,
potentially,
after
branching on a
pair of item,
it may happen
that this same
pair of items
comes up again
with a
fractional sum
value in a
child node.<br>
</div>
<div>To avoid
this problem,
we must ensure
that the pair
selected for
branching has
not been
selected
before in an
ancestor for
branching. If
it has,
another pair
must be
selected.<br>
<br>
</div>
<div>Before
adding a piece
of code that
checks if a
pair was
selected
before for
branching, I
had my program
branching
again and
again on the
same pair of
variable, for
one particular
instance.<br>
<br>
</div>
<div>The code
which computes
the fractional
values of the
pair is now as
follows :<br>
<br>
<pre><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-cm">/* compute weigthts for each order pair */</span>
<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-k">for</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">v</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mi">0</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">v</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o"><</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">nlpcands</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">++</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">v</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">)</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">{</span>
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<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-cm">/* get variable data which contains the information to which constraints/items the variable belongs */</span>
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<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">consids</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">SCIPvardataGetConsids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">vardata</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">)<wbr>;</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-180"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">nconsids</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">SCIPvardataGetNConsids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">vardata</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p"><wbr>);</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-181"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">assert</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">nconsids</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">></span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mi">0</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">);</span>
<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-cm">/* loop over all constraints/items the variable belongs to */</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-184"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-k">for</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">i</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mi">0</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">i</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o"><</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">nconsids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">++</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">i</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">)</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">{</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-185"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">consids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">i</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">];</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-186"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-k">for</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">j</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">i</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">+</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mi">1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">j</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o"><</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">nconsids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">++</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">j</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">)</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">{</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-187"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">consids</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">j</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">];</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-188"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">assert</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o"><</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">);</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-189"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-k">if</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">branchpairs</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">])</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">{</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-190"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-k">continue</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">;</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-191"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">}</span>
<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">pairweights</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">]</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-o">+=</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">lpcandsfrac</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">v</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">];</span>
<span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">assert</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">SCIPisFeasLE</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">scip</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">,</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">pairweights</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">],</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mf">1.0</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">));</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-196"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">assert</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">SCIPisFeasGE</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">(</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">scip</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">,</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">pairweights</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">],</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-mf">0.0</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">));</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-197"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">}</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-198"></a> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">}</span>
<a moz-do-not-send="true" name="m_5442217572206144159_m_-2019721574131620711_m_8327358648935919338_m_-3460604176725813753_m_3956173086178731958_branch_ryanfoster.c-199"></a><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">}</span></pre>
</div>
<div><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">branchpairs</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">]</span> <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p"></span> is
equal to zero if no branching constraints exists on the pair
{id2, id1} for the current node, and it is equal to one
otherwise.
</div>
<div>If a branching was done on the pair id2, id1, then <span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">pairweights</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">[</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id2</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">][</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-n">id1</span><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">] will be
equal to zero, so this pair will not be selected for
branching.
</span></div>
<div><span class="m_5442217572206144159m_-2019721574131620711m_8327358648935919338m_-3460604176725813753m_3956173086178731958gmail-p">Am I right ?</span>
</div>
<div>Kind regards,
</div>
<div>Xavier Schepler
</div>
</div>
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</div></div><pre>______________________________<wbr>_________________
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</blockquote>
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</blockquote>
</div></div></div></blockquote></div>
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