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

[Nigel Galloway]

Is Python any good for you? If so the directory IAJAAR_PY contains some
examples in the file IAJAAR_PY.xps obtainable:

http://sourceforge.net/projects/iajaarh/files/IAJAAR.H.20111120-144507.tar.xz/download

No wrapper is needed to interface from Python to glpk graph functions,
though one might be useful. This document could be used to define the
wrapper, which probably is needed for Java.
 
-- 
  Nigel Galloway
  address@hidden


On Tue, Apr 17, 2012, at 06:18 PM, Andrew Makhorin wrote:
> -------- 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.
>         
> 
> 
> 
> -- 
> Sylvain Fournier
> Analista de Pesquisa Operacional
> 48 3239-2423
> WPLEX Software Ltda.
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> 
> 
> 
> 
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