[Couenne] Analyzing output

[Liffey1986 at gmx.de]

Thanks Pietro, your mail was very helpfull!

One more question concerning the output "...best solution":
For some instances Couenne gives out "1e+050 best solution" at the beginning (before an integer solution was found). I guess this is an upper bound estimation before starting branch-and-bound, or is it computed in a different way?

> > How do I know how every new solution was found? Does the output give 
> > information which heuristic found the solution?
> 
> Yes, every line containing "integer solution". However, only those that 
> improve on the previous value of the cutoff.

I don't see the information about how the solution was found. If the output is "Integer solution of 1166.8 found after 450865 iterations and 21806 nodes (587.68 seconds)", does this mean the solution was found without a heuristic just by solving a node in the b&b-tree? If so, would this line give the information about the heuristic that found the solution, if the was found by a heuristic?

One more question: Is it possible to get information about the memory used during the solving process?

Best,
Ina




-------- Original-Nachricht --------
> Datum: Thu, 28 Feb 2013 11:41:35 -0500 (EST)
> Von: Pietro Belotti <pbelott at clemson.edu>
> An: Liffey1986 at gmx.de
> CC: Couenne mailing list <couenne at list.coin-or.org>
> Betreff: Re: [Couenne] Analyzing output

> Ina,
> 
> > How do I know when the first solution is found? Is this when the output 
> > gives for the first time "integer solution of .... found" or when it 
> > says " .... best solution"?
> 
> The line "integer solution..." indicates that one solution was found and 
> it is stored and used as a cutoff. This happens before the output line 
> containing "... best solution".
> 
> > How do I know how every new solution was found? Does the output give 
> > information which heuristic found the solution?
> 
> Yes, every line containing "integer solution". However, only those that 
> improve on the previous value of the cutoff.
> 
> > If Couenne prints some additional statistics I get an extra line at the 
> > end of the output. What do the following brackets mean:
> 
> [root] the number of linear inequalities that provide a relaxation of the
> nonlinear problem that added at the root node;
> [tot]  the total number of such linear inequalities added;
> [sep]  the time spent in the separation of these inequalities;
> [bb]   the time spent within the branch-and-bound
> 
> This is printed out with the option "display_stats yes" in the couenne.opt
> file, although it is used mostly for debugging purposes.
> 
> I hope this helps.
> 
> Regards,
> Pietro
> 
> --
> Pietro Belotti
> Dept. of Mathematical Sciences
> Clemson University
> email: pbelott at clemson.edu
> phone: 864-656-6765
> web:   http://myweb.clemson.edu/~pbelott
> 
> On Thu, 28 Feb 2013, Liffey1986 at gmx.de wrote:
> 
> > Hi all,
> >
> > I'm trying to analyze the Couenne output, but there is still a few
> things I'm not sure about:
> >
> > How do I know when the first solution is found? Is this when the output
> gives for the first time "integer solution of .... found" or when it says "
> .... best solution"?
> >
> > How do I know how every new solution was found? Does the output give
> information which heuristic found the solution?
> >
> > If Couenne prints some additional statistics I get an extra line at the
> end of the output. What do the following brackets mean:
> > [root]
> > [tot]
> > [sep]
> > [bb]
> >
> > Best Regards
> > Ina
> > _______________________________________________
> > Couenne mailing list
> > Couenne at list.coin-or.org
> > http://list.coin-or.org/mailman/listinfo/couenne
> >