[gecode-users] Difference between rel(), post() and post(tt()) ?
tack at ps.uni-sb.de
Sat Jan 10 20:50:26 CET 2009
> Are the following three constraints equivalent?
> Objective: To extract the d.val() th element in tmpArray into an
> IntValArray groupStudentVal so that further constraint can be
> written on it.
What's an IntValArray?
> tmpArray is int
> groupStudentVal is IntValArray
> d is SetVarGlbValue of a SetVar
What's a SetVarGlbValue?
> (1) post(this, tmpArray[d.val()] == groupStudentVal[index]);
> (2) rel(this, groupStudentVal[index], IRT_EQ, tmpArray[d.val()]);
> (3) post(this, tt(groupStudentVal[index]==tmpArray[d.val()]));
All three statements should do the same thing. However, I don't
understand what d.val() is, and if d is an IntVar, you cannot use its
value when posting constraints, as the value will only be determined
after solving the problem.
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