Hi,
While doing some experimentation with Ciao's FD solver, I found some unusual and apparently wrong answers. The version I tried was "Ciao 1.15.0-13646: Fri Nov 4 11:40:25 CET 2011"
Yo can in fact write constraints like the one below:
?- X.>.12.
X attributed '$fd'(X,[[13|67108863]],[]) ?
The answer is right (if I understand the notation properly), but the same constraint written backwards does not work:
?- 12.<.X.
X attributed '$fd'(X,[],[]) ?
This seems to mean something like "There is no solution for X", which is wrong (although Ciao still responds "yes" for this case).
In general, any constraint written as <constant> .op. <free var> will suffer the same problem.
Was this problem known?. If so, is there any correction for it?.
Thanks. Kind regards,
Jose