<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 class="h5"><br>
<br>
<br>
On 01.04.2014 13:42, 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)">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>