Hello Andrew, I have implemented support for the callback function for the Java wrapper GLPK-Java.
I try to avoid assigning new memory in the wrapper function to avoid possible memory leaks. Hence I use glp_iocp->cb_info for the pointer to the Java environment. When glp_init_iocp is called I set a link to a callback function which calls a Java class. The Java program can add a listener to the Java class if it wants to act on the callback. If in a program multiple problems exist, like in column generation, it is usefull if the call back listener can identify which problem is being solved. Even if the presolver changes some columns the name information is valuable. This is why I would like to see the name of the original problem passed to glp_int_opt also in the problem available during the callback function. NULL returned now does not convey valuable information. --- By the way, I have also been able adjust the wrapper generation by Swig to use glp_error_hook. Hence in the next release of GLPK-Java a failure in a GLPK function will not break the Java application but instead create an exception that can be caught. Best regards Xypron -------- Original-Nachricht -------- > Datum: Sun, 28 Feb 2010 13:04:16 +0300 > Von: Andrew Makhorin <[email protected]> > An: "glpk xypron" <[email protected]> > CC: [email protected] > Betreff: Re: [Bug-glpk] (no subject) > > Why does glp_prob_name(tree) not return the same > > pointer as the one passed to glp_int_opt? > > Because you enabled the mip presolver (iocp.presolve = GLP_ON) in > which case glp_intopt created an internal glp_prob object corresponding > to a presolved mip. This is explained in the reference manual. > > > Please, change the code to provide the problem name > > in the call back function. > > It would be possible to copy symbolic names from the original problem > object, however, it does not have much sense, because the presolved mip > may significantly differ from the original one. Probably there must be > a flag in glp_iocp indicating which names to copy. -- GMX DSL: Internet, Telefon und Entertainment für nur 19,99 EUR/mtl.! http://portal.gmx.net/de/go/dsl02 _______________________________________________ Bug-glpk mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-glpk
