[Osi] How to speed-up flop-osi-cbc ?

John J Forrest jjforre at us.ibm.com
Tue Sep 29 17:16:52 EDT 2009


Renato,

I am not sure what -O2 switches on (or off).  If you go into Cbc (or other 
Coin projects) and just do configure and then look at Makefile, you will 
see that they tend to use -O3 and stuff like -ffast-math and 
-fomit-frame-pointer.  You may also want to use -march=native.  If NDEBUG 
is not defined in your Makefile that would also be a significant hit.

I very much dislike OsiCbc but if that is what is being used then you may 
wish to instantiate it with a non-default CbcStrategy object.  This would 
allow you to have preprocessing which could help.  You can also customize 
that to use more/different cuts and heuristics.

The message level for the OsiCbc object could also be modified before 
handing it to FlopC++.

John Forrest





[Osi] How to speed-up flop-osi-cbc ?

Renato Bruni 
to:
osi
09/29/2009 02:47 PM


Sent by:
osi-bounces at list.coin-or.org







Hello everybody,

we are migrating from Cplex to FlpoC++/Osi/(Cbc or Glpk or Symphony).
We are currently running some tests, but it seems that we need some advice
to speed-up the open source solvers.

We are compiling all with gcc with option -O2 (optimization) but it does 
not
seem much faster than the debug version. Which options would you recommend
for speed? Also, we tried to disable messages from the solvers with the
FlopC++ option "silent", but they write the same messages than before. 
Which
other option we can try? Is there some other speed option (cut 
generation?)
that maybe is disabled and one should enable? And how? Pointers to some
documentation are appreciated.

Thanks a lot in advance.
Best regards,
Renato Bruni

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