Re: [Help-glpk] Write solution on database

[Diana Acosta]

Hi Lance, Hi Heinrich

Thank you so much for help me in my problem and take the time to answer me; I try to implement one of this solution, if I have more questions I hope that I can communicate with you guys and the all of the members of the mail-list :)

Best regards,

Diana

2015-02-23 17:27 GMT-05:00 Heinrich Schuchardt <address@hidden>:

Hello Diana,

glpk-java/examples/java/GlpkSwing.java shows what needs to be done.

Run glpk/examples/tsp.mod and press the terminate button.
You will see an output like

...
+  7505: mip =   6.859000000e+03 >=   6.729000000e+03   1.9% (143; 254)
SEARCH TERMINATED BY APPLICATION
Optimal tour has length 6859
>From node   To node   Distance
        1        14        479
...

In the program a GlpkCallbackListener is registered with

        GlpkCallback.addListener()

In the callback routine of the listener

        GLPK.glp_ios_terminate(tree);

signals that no further nodes shall be evaluated.

In the callback routine you will have to evaluate the elapsed runtime to
decide when to call glp_ios_terminate().

To determine that a feasible solution has been found you could use the
following code in the callback routine:

        int reason = GLPK.glp_ios_reason(tree);

        if (reason == GLPKConstants.GLP_IBINGO) {
                // We have a better integer feasible solution.
        }

Do not set tm_lim with glp_iocp.setTm_lim().

Best regards

Heinrich

On 23.02.2015 20:24, Diana Acosta wrote:
> Hi everybody,
>
> I´m working with GLPK for Java and I implemented a MIP problem using GNU
> MathProg. I have the issue that the time used to obtain a optimal
> solution it´s more longer that I need; for this reason I decide use the
> structure glp_iocp to set the time limit of search; this work fine; but
> I have a problem because my model works with database, I used
> specifically mysql server and an interface with phpmyadmin, and when the
> search stop because the time limit was exceed, I have a feasible
> solution because I know the value of the objective function for MIP
> solution, but the solution, the values of the variables, isn't write on
> the database because this limit stop totally the model (file .mod)
> before can write on database, and there is where I need the answer.
> So I wanna ask if anybody can help me with a function of a structure of
> GLPK, that I can use to write the answer on database or with any form to
> do this,
>
> Thank you so much :)
>
>
> --
> Diana Acosta Rueda

--

Diana Acosta Rueda

Estudiante de Ingeniería de Telecomunicaciones

Universidad de Antioquia