Re: eplex BUG???

From: Joachim Schimpf <j.schimpf_at_icparc.ic.ac.uk> Date: Tue 23 Oct 2001 05:54:27 PM GMT Message-ID: <3BD5AED3.DB475237@icparc.ic.ac.uk> · This archive was generated by hypermail 2.1.8 : Wed 16 Nov 2005 06:08:10 PM GMT GMT

vassilis liatsos wrote:
> 
> The following fails:
> 
> lib(eplex_cplex).
> lp_setup([],max(sum([])),[],H),lp_probe(H,max(sum([])),[],Cost).
> 
> Is that a bug??? That's with CPLEX 7.1 Eclipse  5.2 #35

Yes, it's a bug. lp_probe doesn't catch the empty problem case.

As a workaround, you can redefine lp_probe/4 like this:

:- local lp_probe/4.
lp_probe(H, Obj, ChgCols, Cost) :-
	lp_get(H, vars, VarArr),
	( atomic(VarArr) ->	% catch empty problems
	    arg(1, Obj, Expr),
	    Cost is Expr
	;
	    eplex:lp_probe(H, Obj, ChgCols, Cost)
	).

Cheers,
Joachim