Re: [Help-glpk] How can I use functions in glptsp.c to solve TSPs using glpk?

[ikarus]

Thanks a lot Xypron!

actually I hacked a bit the code in glptsp.c and I use it as a c function to
create a csv file from a TSPLIB file and then I called your .mod file to
solve TSPs from the same c program (and produce also a  graphical output).

However, the solutions I get from your model are not feasible tours ...
well, maybe I did something wrong, but are you sure that your model works to
enforce the creation of feasible tours? i didn't have time to go into the
details of your model actually.

I also used the model proposed in:
http://archive.ite.journal.informs.org/Vol7No1/LeeRaffensperger/

and it seems to work (well, I tested it for small instances, less tan 100
cities)

Best regards,

ikarus


xypron wrote:
> 
> Hi,
> 
> tsp_read_data() is not part of the documented API (see doc/glpk.pdf).
> 
> For teaching purposes a good idea would be to provide the example as a CSV
> file
> and read it with command "table IN" inside a gmpl model (see
> doc/tables.pdf).
> 
> Only a few changes to examples/tsp.mod are needed:
>  http://www.nabble.com/file/p25670352/tsp.zip tsp.zip 
> 
> How to output a SVG graphic from glpsol is shown in
>  http://www.nabble.com/file/p21151721/tsp_svg.tar.gz tsp_svg.tar.gz 
> 
> Best regards,
> 
> Xypron
> 
> 
> ikarus wrote:
>> 
>> Hi,
>> I saw that glpk's distribution includes glptsp.c and glptsp.h (that look
>> undocumented, by the way). These files seem to provide only routines to
>> read data from a TSPLIB file and to compute the distance between two
>> cities. How can I use these in combination with the other functions
>> included in glpk to actually solve a tsp instance?
>> 
>> I would like to do something like:
>> 
>> TSP *tsp = tsp_read_data("berlin52.tsp");
>> glp_intopt(tsp, some_params);
>> 
>> but clearly glp_intopt needs another type of data as problem descriptor
>> ...
>> Is there any way to do something similar? 
>> ... or a script to convert the TSPLIB format in GMLP? 
>> (by the way, I know that glpk is not a good option to solve large TSP
>> instances, but I need it for teaching purposes)
>> 
>> Thanks!
>> 
> 
> 

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