[Gecode] Equality, variable aliasing and AllDistinct

[Guido Tack]

Hi!

In a discussion with Thorsten and Didier, a technical question came up:

In Mozart, {FD.distinct [A B C]} will immediately detect failure if A=B. This 
is not the case for Gecode, where A=B just posts a propagator instead of 
identifying the two variables. I know from a discussion with Christian that 
he thinks that identifying variables in the store is a bad thing because it 
makes the system much more complicated. So the question was whether there is 
either a simple solution that enables distinct to test for aliasing, or 
whether this is a border case that is not interesting in practical 
applications.

	Guido

-- 
Guido Tack
Programming Systems Lab
http://www.ps.uni-sb.de/~tack