[eclipse-clp-users] Possible bugs solving FlatZinc problems

From: Roberto Castaņeda <rcas_at_...277...>
Date: Sun, 29 Aug 2010 17:01:25 +0000
Hi!

I have started to build a random generator of FlatZinc constraint problems and
I am comparing the output given by different solvers (ECLiPSe, Gecode, JaCoP,
etc.). During the first runs, I detected a couple of discrepancies between 
ECLiPSe and the other solvers which I think are worth reporting:

1) This FlatZinc input:

var 8..9: v4 :: output_var;
constraint int_gt(v4, v4);
solve maximize v4;

gives this output in ECLiPSe:

% Starting search
Found a solution with cost -8
v4 = 8;

While the other solvers report 
=====UNSATISFIABLE=====

(The same happens with boolean variables and/or *_lt constraints).


2) This FlatZinc variable declaration:

var -6..-5: v1 :: output_var;

produces a parsing error in ECLIPSe:

pipe stream input: syntax error: postfix/infix operator expected
| var -6..-5: v1 :: output_var;
|         ^ here
Error: Unexpected end of FlatZinc input
Aborting execution ...

This input is accepted by the other solvers.


If I am not missing anything and these are bugs, I can report them in the
Bugs Database, I just wanted to make sure I would not be adding noise to it.

Regards,

Roberto Castaņeda Lozano
Received on Sun Aug 29 2010 - 17:06:26 CEST

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