[gecode-users] usage of abs() constraint
Stanimir Dragiev
stanio at cs.tu-berlin.de
Mon Oct 15 21:53:08 CEST 2007
Hello to all on the list!
I was pretty frustrated, that I couldn't get following to work:
---- code ---
//init var_a, var_b
IntVar abs_diff(space, 0, MAX_DIFF);
IntVar signed_diff = post(space, var_a - var_b);
abs( space, signed_diff, abs_diff);
---- end ---
But I found an example in the gecode example models using abs, and I turned
it into:
---- code ---
//init var_a, var_b
IntVar abs_diff(space, 0, MAX_DIFF);
abs_diff = post(space,
abs(space,
minus(space, var_a, var_b,
ICL_DOM),
ICL_DOM),
ICL_DOM);
---- end ---
The latter one does what I expect, while the first leaves abs_diff with it's
original bounds: 0 to MAX_DIFF.
Now I'm a little more frustrated than before, since I don't understand what is
going on :o)
Is it not expected, that both behave the same way?
--
cheers
stanio
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