[Cbc] Performance

[Anthony Presley]

All:

I just thought I'd post some performance data we saw with a data set.
It's an integer minimization problem.  I downloaded and tried out cbc 2
(in comparison to cbc 1.2), and ran the model with these parameters (in
both versions):

	import file
	sec 82
	allow 82
	strong 0
	threads 3
	solve

I also tried with threads -1, 1, 2, 3, and 0.

Overall, the end result is that cbc 1.2 takes 30 - 32 seconds, and cbc
2.0 takes about 78 - 80 seconds.

The only difference that I know of (besides the version and features in
the software) is that cbc 2.0 was compiled with
--enable-cbc-parallel  .... ie, I so no speed improvement with parallel
enabled.

I haven't tried cbc 2 without the "--enable-cbc-parallel".

We will continue using CBC 1.2, but just wanted to see if there was
anything we might want to look at that may be slowing down the solution.
Did some of the defaults change?


--
Anthony