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<div class="moz-cite-prefix">Sourav,<br>
<br>
Cbc reads arguments in order so you need to put -threads 6 before
-solve.<br>
<br>
Problem is big, but switching off preprocessing is probably
counter productive. Given those statistics, I would expect
preprocessing to reduce size considerably.<br>
<br>
If you want to send me the problem (compressed), I amy have time
to take a quick look.<br>
<br>
John Forrest<br>
On 22/05/14 13:30, Sourav Garg wrote:<br>
</div>
<blockquote
cite="mid:CAE9Jt7HMyWwd6iLEtxM7JX1X45Z8WBtn1CnzmS0-cmYVy7BrMg@mail.gmail.com"
type="cite">
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<div dir="ltr">Thanks John.
<div><br>
</div>
<div>Cbc was what I actually needed.</div>
<div>I am using the standalone executable of cbc which solves
the Binary Integer program that I provide using a .mps file.</div>
<div>For some instances I get the solution within seconds, but
for one of my inputs, it took one day to complete and get an
optimal solution. The corresponding stdout logs were like
this:</div>
<div><br>
</div>
<div><i>"</i></div>
<div><i>...</i></div>
<div><i>Problem BIP has 287088 rows, 7346 columns and 509272
elements<br>
</i></div>
<div><i>...</i></div>
<div><i>...</i></div>
<div><i>...</i></div>
<div><i><br>
</i></div>
<div>
<div><i>Result - Optimal solution found</i></div>
<div><i><br>
</i></div>
<div><i>Objective value: 0.00004017</i></div>
<div><i>Enumerated nodes: 92760</i></div>
<div><i>Total iterations: 85136638</i></div>
<div><i>Time (CPU seconds): 85473.77</i></div>
<div><i>Time (Wallclock seconds): 85683.41</i></div>
<div><i><br>
</i></div>
<div><i>Total time (CPU seconds): 85474.08 (Wallclock
seconds): 85683.75</i></div>
<div><i><br>
</i></div>
</div>
<div><i>"</i></div>
<div>Reason is probably the size of data.</div>
<div>I realized that there is an option of using multiple
threads while running cbc (source: man page of Ubuntu), I
tried to use that:</div>
<div><br>
</div>
<div>
<div>$ cbc myFIle.mps solve -threads 6 -solution cbcSoln.txt</div>
</div>
<div><br>
</div>
<div><i>"<br>
</i></div>
<div><i>...</i></div>
<div><i>threads was changed from 0 to 6<br>
</i></div>
<div><i>..</i></div>
<div>"</div>
<div><br>
</div>
<div>It gives confirmation of changing threads number, but I
don't see any of my other cores being used, just a single
processor at 100%. (I am using Dell Precision T5500 Processor:
Intel® Xeon(R) CPU X5675 @ 3.07GHz × 12, Memory: 47.2 GB).</div>
<div>I want to reduce the time it takes for finding the
solution. Along with switching off the cuts and preprocess
options to save time, can I further change some more
parameters so that I can save time and get an optimal
solution?</div>
<div><br>
</div>
<div>Thanks,</div>
<div>Sourav</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Tue, May 20, 2014 at 7:08 PM, John
Forrest <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:john.forrest@fastercoin.com" target="_blank">john.forrest@fastercoin.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote">
<div>
<div>Sourav,<br>
<br>
1. -maximize is just a flag - you should follow it with
-dualsimplex or similar.<br>
2. Clp does not solve integer problems - Cbc does so
download that.<br>
<br>
John Forrest
<div>
<div class="h5"><br>
On 20/05/14 10:42, Sourav Garg wrote:<br>
</div>
</div>
</div>
<blockquote type="cite">
<div>
<div class="h5">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>
<div>Hello,<br>
<br>
</div>
I am using Clp1.15.6 on
an Ubuntu 12.04 machine.<br>
</div>
I have compiled and
installed the executable
as mentioned in the readme
install notes, which went
successful.<br>
</div>
<br>
1. I have been trying some
linear programs using the
Clp executable with a mps
file. It gives me right
solution for a minimization
problem (which is the
default direction of
optimisation), but it
doesn't give me correct
solutions for maximisation
problems.<br>
</div>
<br>
For maximisation, I use it as
follows:<br>
</div>
./clp ./my.mps -maximize
-solution solFile<br>
</div>
<br>
What I get in the file is:<br>
</div>
status unknown<br>
</div>
objective value 0<br>
</div>
columns val 0 as well..<br>
<br>
</div>
2. Apart from this, I have a Binary
Integer Program problem, for minimisation,
in which I pass all the bounds as BV in
the mps file.<br>
</div>
But in the solution I get floating point
values for the non zero columns instead of
getting the value of 1. I wanted to know if
Binary Integer Programming is supported with
the library?<br>
<br>
</div>
Thanks,<br>
</div>
Sourav<br>
</div>
<div>
<div>
<div><br>
</div>
</div>
</div>
</div>
<br>
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