[gecode-users] Reified MiniZinc Decompositions of Globals are overridden for Gecode

[Alexander Schiendorfer]

Hi everyone,

I have a question regarding the MiniZinc globals definition of lex_less 
(among others) in Gecode,
in particular how their reified version is treated.

Say I wanted to solve the following model:

% test if lexless can be used in reified mode
array[1..5] of var 0..10: x;
array[1..5] of var 0..10: y;

include "globals.mzn";
constraint alldifferent(x);

constraint lex_less(x, y) \/ x[1] = 9;
solve satisfy;


Since, for example, the Gecode-specific "lex_less.mzn" file overwrites 
all predicate definitions there, we also
lose the "lex_less_int_reif" decomposition specified in the standard 
MZN-library.

Wouldn't it be nicer to have this decomposition available until there is 
a reified variant of "lex_less"?
I tried copying "predicate lex_less_int_reif(...)" from "std" to 
Gecode's "lex_less.mzn" and it made the above
model solvable.

Is there a particular reason for not doing this?

Cheers,
Alex

-- 
Alexander Schiendorfer, M.Sc.
Institute for Software & Systems Engineering
Raum 3043, Gebäude N
Universität Augsburg

Web: http://www.informatik.uni-augsburg.de/lehrstuehle/swt/se/staff/aschiendorfer/
Tel.: +49 (821) 598 - 2196
E-Mail: alexander.schiendorfer at informatik.uni-augsburg.de

SASO’16 - Tenth IEEE International Conference on Self-Adaptive and Self Organizing Systems
Augsburg, Germany, 12-16 September 2016
@SASO2016Conf
http://uni-augsburg.de/saso2016 – Submit! Announce! Participate!