[Couenne] Analyzing output

[Liffey1986 at gmx.de]

Great, now I understand it a lot better. Thanks for the fast and detailled help.

Best,
Ina
-------- Original-Nachricht --------
> Datum: Thu, 28 Feb 2013 12:12:29 -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,
> 
> > 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?
> 
> Yes. It simply means no feasible solution is found so the upper bound is 
> +infinity.
> 
> >>> 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?
> 
> Sorry for overlooking this in my answer. Feasible solutions can be found 
> by a heuristic, by the LP solver (when the LP solution happens to be 
> feasible for the MINLP as well) and by strong branching, if I remember 
> correctly. What you quote is the typical output when the solution is found
> by the LP solver.
> 
> > If so, would this line give the information about the heuristic that 
> > found the solution, if the was found by a heuristic?
> 
> Yes.
> 
> > One more question: Is it possible to get information about the memory 
> > used during the solving process?
> 
> Couenne does not keep track of it, and I'm not sure if Cbc does. Maybe 
> you can use some generic command line tools, but I am not knowledgeable 
> enough to help you on this.
> 
> 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:
> 
> > 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
> >>>
> >