Re: [Help-glpk] Patch for writing pseudo-boolean problems

[Andrew Makhorin]

> please find enclosed a diff with an additional API-command
> lpx_write_pb that writes an instance in (possibly normalized)
> Pseudo-Boolean format. It is also incorporated in glpsol.

Please post me the source code. I cannot find it.

> The main problem so far is that the different PB solvers have qutie
> different requirements on the input. However, the normalized one
> follows the PB competition guidelines. There should probably be some
> checking that the variables are binary, but I skipped that as there
> might be cases where it may be useful.

> I would also like to add two requests:

> * An API-call to set the amount of available memory.

I added the API routine glp_mem_limit, which will appear in 4.19.
Below here is its source code, so you can add it right now (to the end
of file glpapi10.c).

/***********************************************************************
*  NAME
*
*  glp_mem_limit - set memory usage limit
*
*  SYNOPSIS
*
*  void glp_mem_limit(int limit);
*
*  DESCRIPTION
*
*  The routine lib_mem_limit limits the amount of memory available for
*  dynamic allocation (in GLPK routines) to limit megabytes. */

void glp_mem_limit(int limit)
{     if (limit < 0)
         xfault("glp_mem_limit: limit = %d; invalid parameter\n",
            limit);
      lib_mem_limit(ulmul(ulset(0, 1 << 20), ulset(0, limit)));
      return;
}

> * An API-call to set a hook that is called with a tree pointer (or
>    just the objective value) when a new MIP solution is found.

I would not like to add such a hook to lpx_integer, because it will
be replaced by glp_integer. However, you can insert a necessary call
into the routine record_solution (see file glpmip02.c).


Andrew Makhorin