Hello Christian,
Thanks for your answer.
1) I realized during the WE that i don't really understand the difference
between an "rel" and a "expr" (not from a pure C++ point of view).
2) The example that i have provided point on some confusion :
I have written status(t,m) which is correct but
status(succ(t,m)) is incorrect, the correct form is status(succ(t,m),m).
Thus, element(Status, Succ(t,m)) is syntactically correct but wrong.
3) I've found a similar solution than yours (after hard work!). With however
a big difference (probably because i'm perverted by years of imperative
programming) :
I have written :
if (Status(t, m) != 3)
{
BoolVar not_inprogress =
expr(*this, element(Status.row(m), Succ(t,m)) != 3);
BoolVar toa_of_succ =
expr(*this, element(Time.row(m), Succ(t, m)) > ETOA[m] + 10);
rel(*this, not_inprogress >> toa_of_succ);
}
Thus, the (Status(t, m) != 3) is not part of the constraint, what are the
implications of doing this ? (that's more a constraint programming question
than a question related to gecode, i admit).
4) Is it a good point to be able to express things like that (and i could
may be try to propose some patches) :
Example 1 :
==========
expr1.1 : expr(*this, element(Status.row(m), Succ(t,m)) != 3)
compile, but :
expr1.2 : expr(*this, Status(Succ(t,m), m) != 3);
don't, however, the first form seems to me more elegant.
Example 2 :
===========
expr2.1 :
IntVar task(*this, t, t);
expr(*this, Succ(t,m) != task);
compile, but :
expr2.2 : expr(*this, Succ(t,m) != t)
don't. Here again, the second form seems more elegant.
Best,
Philippe
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