Re: [Help-glpk] Branch and cut tree representation.

[glpk xypron]

Hello Andrew,

currently multiple users are working on integrating GLPK into
an IDE (e.g. Gusek).

In such an IDE it makes sense to have graphs displaying the
development of the solution and updating these charts during
the execution.

As example have a look at ILOG OPL Studio, where you find
an online chart showing the development of the lower bound
and the best integer solution.

For such an IDE online graph a hook function (or callback
function) is needed, which should be defined in glp_iocp.

Of cause for the standalone solver glpsol writing to a file
makes sense. Glpsol could use the hook by placing a hook
function provided by the API into glp_iocp.

Best regards

Xypron
-------- Original-Nachricht --------
> Datum: Thu, 25 Feb 2010 04:23:16 +0300
> Von: Andrew Makhorin
> An: Brady Hunsaker
...
> > I would love to get feedback from people who try BAK out.
> 
> > Andrew, I'm going to follow up with you to see if it is possible to 
> > incorporate the changes to GLPK directly into GLPK.
> 
> I agree with Xypron and think that having such feature in glpk would
> be useful.
> 
> It is quite easy to make necessary changes in glp_intopt to collect
> all necessary information. However, one question has to be resolved:
> where to store the information? It can be stored either in the memory
> (in which case even the glp_graph data structure could be used to
> represent the tree), or in a text file, say, in a DIMACS-like format.
> I would choose the latter case, because the tree inspection is a kind
> of post-optimal analysis; in this case the filename could be passed to
> glp_intopt via the glp_iocp parameter block.
> 
> Best regards,
> 
> Andrew Makhorin

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