<div dir="ltr"><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Hi Gerald, <br><br>>>is the delay flag of your pricer set to TRUE? <br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">
Yes,<br><br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)"><br>>>When you create and
add new variables, do you set the initial flag of the variables to
TRUE? <br>Which parameter corresponds to the initial flag?<br><br>>>You add them with SCIPaddPricedVar()? <br>Yes,<br>>>Can you double-check,
that the variables you create really have the same meaning.<br>Yes,<br><br>>> If so,
please check the following for the "old" variable:<br>
>>- is it in the LP? -> SCIPvarIsInLP()<br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">I did not use SCIPvarIsInLP() ( I do not know how to use it) but in each iteration I checked, s<br>
</div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)"><br>
>>- what are the reduced cost of the variable ->
SCIPgetVarRedcost()<br>
>>- does this corresond to the reduced cost you are computing for
the new variable?<br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">When I add SCIPgetVarRedCost(), after one iteration it returns error: <br> ERROR: Error <1516178640> in function call<br>
</div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">But in this iteraion, the reduced cost are exactly the same as what I calculate.<br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">
How can I find out what is wrong here?<br>Note that without SCIPgetVarRedCost(), I do not get any error.<br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">I have attached the procedure in which I add new variables.<br>
<br></div><div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Regards,<br>Mahdi<br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 1 April 2014 14:35, Gerald Gamrath <span dir="ltr"><<a 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 bgcolor="#FFFFFF" text="#000000">
<div>Hi Mahdi,<br>
<br>
is the delay flag of your pricer set to TRUE? When you create and
add new variables, do you set the initial flag of the variables to
TRUE? You add them with SCIPaddPricedVar()? Can you double-check,
that the variables you create really have the same meaning. If so,
please check the following for the "old" variable:<br>
- is it in the LP? -> SCIPvarIsInLP()<br>
- what are the reduced cost of the variable ->
SCIPgetVarRedcost()<br>
- does this corresond to the reduced cost you are computing for
the new variable?<br>
<br>
Best,<br>
Gerald<div><div class="h5"><br>
<br>
On 01.04.2014 14:51, mahdi noorizadegan wrote:<br>
</div></div></div><div><div class="h5">
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Hi
Gerald,<br>
<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Please
find the attachments.<br>
<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Thanks,<br>
Mahdi<br>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On 1 April 2014 13:30, Gerald Gamrath <span dir="ltr"><<a 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 bgcolor="#FFFFFF" text="#000000">
<div>Hi Mahdi,<br>
<br>
Nalan sent these log files already. You can print
statistics by "disp stat" in the interactive shell or
calling SCIPprintStatistics().<br>
<br>
Best,<br>
Gerald
<div>
<div><br>
<br>
<br>
On 01.04.2014 13:42, mahdi noorizadegan wrote:<br>
</div>
</div>
</div>
<div>
<div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">Hi
Gerald,<br>
<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">The
constraints are modifiable. <br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">I
am nit sure if you have the whole log files.<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">
I have attached again the log files.<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">I
was wondering if you could let me know what you
mean by printing the statistics after stopping?<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">What
do you want to see in the log files?<br>
<br>
</div>
<div class="gmail_default" style="font-family:georgia,serif;color:rgb(32,18,77)">
Regards,<br>
Mahdi<br>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On 1 April 2014 10:04,
Gerald Gamrath <span dir="ltr"><<a 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 bgcolor="#FFFFFF" text="#000000">
<div>Dear Nalan,<br>
<br>
Mahdi's mail didn't reach the mailing
list, because he also sent it from a mail
address not registered for the list.<br>
<br>
It seems like your problem is not caused
by the branching, on two of the three log
file, you already stop before the first
branching is performed.<br>
<br>
If you could print the statistics after
stopping and send the log files again,
this would help us a lot to identify the
problem.<br>
<br>
Did you change all constraints to
modifiable to which you add variables
during solving? Otherwise, propagation
might fix some of your priced variables to
0 and it might happen that pricing
regenerates them again and again. Except
for that, my best guess would be that you
somehow compute the reduced cost wrongly.<br>
<br>
Best,<br>
Gerald
<div>
<div><br>
<br>
<br>
On 01.04.2014 09:20, Gulpinar, Nalan
wrote:<br>
</div>
</div>
</div>
<div>
<div>
<blockquote type="cite">
<div style="font-size:12pt;font-family:Calibri,Arial,Helvetica,sans-serif">
<p><span style="font-size:12pt">Dear
Ambros, </span><br>
</p>
<div style="color:#282828">
<div>
<div style="color:#000000;font-size:12pt;font-family:calibri,arial,helvetica,sans-serif">
<p><br>
</p>
<p>Thank you for your prompt
reply. As you suggested, I
am resending my previous
email. <br>
</p>
<p><br>
</p>
<p>I am writing this
email about the problem we
have faced with SCIP. <br>
</p>
<p><span style="font-size:12pt">As Mahdi
reported yesterday
(please </span><span style="font-size:12pt">s</span><span style="font-size:12pt">ee
his email </span><span style="font-size:12pt">b</span><span style="font-size:12pt">elow),
we have checked the </span><br>
</p>
<p>code several <span style="font-size:12pt">times,
and even t</span><span style="font-size:12pt">rie</span><span style="font-size:12pt">d</span><span style="font-size:12pt"> to
run its alternative
formulation but the
problem </span></p>
<p><span style="font-size:12pt"></span><span style="font-size:12pt">remains
the </span><span style="font-size:12pt">same.
I have also attached the
output of three instances
of the model. </span></p>
<p><span style="font-size:12pt">I
hope </span><span style="font-size:12pt">this helps
you to identify the
problem. </span></p>
<p><span style="font-size:12pt"><br>
We use column generation
procedure where continuous
variables are added into
the </span></p>
<p><span style="font-size:12pt">master
problem and branch and
bound procedure is used to
solve the master problem. </span></p>
<p><span style="font-size:12pt">But
after some iterations it
cannot be improved. For
example, as you will see
from </span></p>
<p><span style="font-size:12pt">log
file.rtf, we have the
following output. </span></p>
<p><span style="font-size:12pt"><br>
</span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt">I
am looking forward to
receiving your reply and
suggestions. </span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt"><br>
</span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt">Thank
you for your help at
advance. </span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt"><br>
</span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt">Best
regards</span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt"><br>
</span></p>
<p style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px"><span style="font-size:12pt">Nalan </span></p>
<div style="font-family:calibri,arial,helvetica,sans-serif;font-size:16px">
<p><br>
</p>
<div style="font-family:tahoma;font-size:13px">_____________________________________________<br>
Nalan Gulpinar, Ph.D. <br>
Associate Professor of
Operational Research<br>
Warwick Business School<br>
The University of Warwick,
Coventry, CV4 7AL, UK.<br>
Tel: <a href="tel:%2B44%20%280%29%2024%207652%204491" value="+442476524491" target="_blank">+44 (0)
24 7652 4491</a><br>
Fax: <a href="tel:%2B44%20%280%29%2024%207652%204539" value="+442476524539" target="_blank">+44 (0)
24 7652 4539</a><br>
Email: <a href="mailto:Nalan.Gulpinar@wbs.ac.uk" target="_blank">Nalan.Gulpinar@wbs.ac.uk</a><br>
_____________________________________________<br>
</div>
</div>
<p><span style="font-size:12pt"><br>
</span></p>
<p><span style="color:#20124d;font-family:georgia,serif">leastJ/leastT=
0,0, minRedCost: -43.3</span><span style="color:#20124d;font-family:georgia,serif">117</span><span style="font-size:12pt"><br>
</span></p>
<div style="color:#20124d;font-size:16px;font-family:georgia,serif">
<p>total cost= 1173.06,
10.84, 882.22, 280, z_134</p>
<p>134, add new variables</p>
<p> 0.1s| 1 | 0 |
203 | - | 725k| 0 |
33 | 206 | 115 | 205 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> time | node | left |LP
iter|LP it/n| mem |mdpt
|frac |vars |cons |cols
|rows |cuts |confs|strbr|
dualbound | primalbound
| gap </p>
<p> 0.1s| 1 | 0 |
205 | - | 725k| 0 |
36 | 206 | 115 | 206 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> </p>
<p> leastJ/leastT= 2,0,
minRedCost: -90.6829</p>
<p>total cost= 532.45, 1.05,
363.4, 168, z_135</p>
<p>135, add new variables</p>
<p> 0.1s| 1 | 0 |
205 | - | 727k| 0 |
36 | 207 | 115 | 206 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> 0.1s| 1 | 0 |
205 | - | 727k| 0 |
23 | 207 | 115 | 207 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> </p>
<p> leastJ/leastT= 2,0,
minRedCost: -90.6829</p>
<p>total cost= 532.45, 1.05,
363.4, 168, z_136</p>
<p>136, add new variables</p>
<p> 0.1s| 1 | 0 |
205 | - | 729k| 0 |
23 | 208 | 115 | 207 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> 0.1s| 1 | 0 |
209 | - | 729k| 0 |
23 | 208 | 115 | 208 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> </p>
<p> leastJ/leastT= 1,0,
minRedCost: -88.4043</p>
<p>total cost= 350.84,
31.14, 151.7, 168, z_137</p>
<p>137, add new variables</p>
<p> 0.1s| 1 | 0 |
209 | - | 731k| 0 |
23 | 209 | 115 | 208 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> </p>
<p> leastJ/leastT= 1,0,
minRedCost: -88.4043</p>
<p>total cost= 350.84,
31.14, 151.7, 168, z_138</p>
<p>138, add new variables</p>
<p> 0.1s| 1 | 0 |
209 | - | 733k| 0 |
23 | 210 | 115 | 208 | 115
| 0 | 0 | 0 |
-- | 7.654555e+03
| Inf </p>
<p> </p>
<p> leastJ/leastT= 1,0,
minRedCost: -88.4043</p>
<p>total cost= 350.84,
31.14, 151.7, 168, z_139</p>
<p>139, add new variables<br>
</p>
<br>
This goes on......<br>
</div>
<div style="color:#282828">
<div dir="ltr">
<div> <br>
</div>
</div>
<div>
<div dir="ltr">
<div class="gmail_quote">
<div>
<div>
<div dir="ltr"><br>
<div class="gmail_quote">----------
Forwarded
message
----------<br>
From: <b class="gmail_sendername">mahdi
noorizadegan</b>
<span dir="ltr"><<a href="mailto:m.noorizadegan@gmail.com" target="_blank">m.noorizadegan@gmail.com</a>></span><br>
Date: 31 March
2014 18:37<br>
Subject:
Column
generation<br>
To: <a href="mailto:Scip@zib.de" target="_blank">Scip@zib.de</a><br>
<div dir="ltr">
<div style="font-family:georgia,serif;color:#20124d"><br>
</div>
<div style="font-family:georgia,serif;color:#20124d">Hi,<br>
<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">I
have been
trying to
solve a
problem by the
column
generation
method.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">The
variables
which are
being added to
the master
problem were
binary<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">so
I had the
problem with
the branch and
bound
procedure.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">I
changed the
formulation
and added new
dummy binary
variables and
changed<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">the
type of the
other
variables to
continuous.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">So
there should
not be any
problem with
the branch and
bound
producer.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">However,
I still have
problems. It
keeps adding
the same
column after
few
iterations!<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">For
example for a
simple
instance, the
objective
function value
is 350.84,<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">the
dual value is
439.24
therefore the
reduced cost
is
-439.24+350.84=-88.40.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">When
this new
variable is
added to the
problem, in
the next
iteration this
variable is
again <br>
</div>
<div style="font-family:georgia,serif;color:#20124d">identified
and added!<br>
<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">I
have checked
the pricing
problem. It
seems correct
and I could
not find any
mistake.<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">I
was wondering
if you could
help me and
let me know
what can be
wrong!?<br>
<br>
</div>
<div style="font-family:georgia,serif;color:#20124d">Thanks
and best,<br>
Mahdi<br>
</div>
</div>
</div>
<br>
</div>
</div>
</div>
</div>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
<br>
</div>
</div>
</div>
<br>
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<br>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</blockquote>
<br>
</div></div></div>
</blockquote></div><br></div>