[Help-glpk] [Fwd: Re: Building a graph on the fly]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Sylvain Fournier <address@hidden>
To: Andrew Makhorin <address@hidden>
Subject: Re: [Help-glpk] Building a graph on the fly
Date: Tue, 17 Apr 2012 10:12:27 -0300

Hi Andrew,

Thanks for your quick answer. In fact, I am looking for an example in
Java, as I can't find how to create a C struct using the Java routines,
and how to use the offsetof macro.
Does the '_' prefix for the class names _glp_graph, _glp_arc and
_glp_vertex (in Java) mean something special? (I guess they are
supported, as they can be found in the glpk-java.pdf documentation)
Best regards.


2012/4/16 Andrew Makhorin <address@hidden>
        > I need to solve a minimum cost flow problem in Java, and for
        this I'd
        > like to use the Out-Of-Kilter algorithm included in GLPK. I
        saw there
        > is a way to build the graph reading the information from a
        text file
        > (glp_read_graph), however I wonder whether I can do it on the
        fly,
        > using some routines that modify the graph.
        > I saw I can use for example glp_create_graph,
        glp_add_vertices,
        > glp_add_arc. On the other hand, I can't find a way to create
        or modify
        > the data associated with a vertex (demand) or an arc
        (capacity, cost).
        > I had no success in searching either into the mailing list
        archives,
        > or in the files included in the GLPK distribution (examples
        and
        > documentation). Did I miss something?
        
        
        Please see the example in Subsection 2.1.5 "Solve minimum-cost
        flow
        problem with the out-of-kilter algorithm" of the document "GLPK:
        Graph
        and Network Routines" (doc/graph.pdf). You need to define your
        own
        structs, one for each node and one for each arc of the network,
        which
        include fields to store node supply/demand, arc capacity, etc.
        When you
        call glp_mincost_okalg, you specify with the standard offsetof
        macro
        where the input data are stored in your structs and to where the
        routine
        should store the solution components.
        



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