[eclipse-clp-users] How to extend lib(ic) to get stronger propagation?

From: Ulrich Scholz <Ulrich.Scholz_at_...10...>
Date: Tue, 17 Nov 2009 13:25:15 +0100
Hi again,

It is clear that a constraint package cannot detect and propagate all
possible simplifications.  But sometimes, a specific simplification can be
of great help.

Consider the following constraint program.

  [eclipse 3]: lib(ic), [A, B] :: [0, 100], A #=< B, B #=< A.

  A = A{[0, 100]}
  B = B{[0, 100]}


  Delayed goals:
          -(B{[0, 100]}) + A{[0, 100]} #=< 0
          B{[0, 100]} - A{[0, 100]} #=< 0
  Yes (0.00s cpu)


It would really help me if (an extended) ic would simplify this case to
A#=B.  Labeling is no option for me, I need to detect this case early.

Could you suggest an approach?  Maybe checking some conditions on every
posting of #=<?  Depending on the outcome, I could thenpost one of #=, #<,
or #=<.

Thanks,

Ulrich
Received on Tue Nov 17 2009 - 12:24:27 CET

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