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

[Andrew Makhorin]

Hi Xypron,

> 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.

Probably a more general way would be using a callback routine
to notify the application program about various events in the
branch-and-cut algorithm. Nevertheless, I do not see much sense in
displaying the graphs during the search (I think such feature is
a kind of "whistles and bells" :). I would propose to start from
a version, where all necessary information is accumulated in a file
and then passed to a package like BAK for further processing.


Andrew Makhorin