[eclipse-clp-users] Repair library propagation issue

I’m experiencing unexpected propagation behavior using the repair library.   I would expect the following to say the ic constraint is in conflict as the tentative assignment should violate the constraint.  It's as if the arithmetic operator + is being delayed/suspended.

[eclipse 70]: [X,Y] :: 0..3, ic:(X #= Y + 1) r_conflict_prop cs, X tent_set 1, Y tent_set 1, conflict_constraints(cs,C).

X = X{ic : 0 .. 3, repair : 1}
Y = Y{ic : 0 .. 3, repair : 1}
C = []

There are 6 delayed goals. Do you want to see them? (y/n) 

Delayed goals:
	repair : unify_to_tent_if_ground_args(X{ic : 0 .. 3, repair : 1}, X)
	repair : sum_update(1 * Y{ic : 0 .. 3, repair : 1}, 1, X{ic : 0 .. 3, repair : 1}, 'SUSP-_743-susp')
	repair : unify_to_tent_if_ground_args(X{ic : 0 .. 3, repair : 1}, Y{ic : 0 .. 3, repair : 1} + 1)
	monitor_conflict(ic : (X{ic : 0 .. 3, repair : 1} #= X))
	monitor_tenable(X{ic : 0 .. 3, repair : 1}, s(yes))
	monitor_tenable(Y{ic : 0 .. 3, repair : 1}, s(yes))
Yes (0.00s cpu)


If I use r_conflict instead it behaves as expected:


[eclipse 71]: [X,Y] :: 0..3, ic:(X #= Y + 1) r_conflict cs, X tent_set 1, Y tent_set 1, conflict_constraints(cs,C).

X = X{ic : 0 .. 3, repair : 1}
Y = Y{ic : 0 .. 3, repair : 1}
C = [ic : (X{ic : 0 .. 3, repair : 1} #= Y{ic : 0 .. 3, repair : 1} + 1)]

There are 7 delayed goals. Do you want to see them? (y/n) 

Delayed goals:
	repair : unify_to_tent_if_ground_args(X{ic : 0 .. 3, repair : 1}, X)
	repair : sum_update(1 * Y{ic : 0 .. 3, repair : 1}, 1, _766{2}, 'SUSP-_743-susp')
	monitor_tenable(_766{2}, s(yes))
	repair : unify_to_tent_if_ground_args(_766{2}, Y{ic : 0 .. 3, repair : 1} + 1)
	monitor_conflict(ic : (X{ic : 0 .. 3, repair : 1} #= _766{2}))
	monitor_tenable(X{ic : 0 .. 3, repair : 1}, s(yes))
	monitor_tenable(Y{ic : 0 .. 3, repair : 1}, s(yes))
Yes (0.00s cpu)


If I simplify the constraint to #\= and use r_conflict_prop it behaves as expected:


[eclipse 72]: [X,Y] :: 0..3, ic:(X #\= Y) r_conflict_prop cs, X tent_set 1, Y tent_set 1, conflict_constraints(cs,C).

X = X{ic : 0 .. 3, repair : 1}
Y = Y{ic : 0 .. 3, repair : 1}
C = [ic : (X{ic : 0 .. 3, repair : 1} #\= Y{ic : 0 .. 3, repair : 1})]

There are 6 delayed goals. Do you want to see them? (y/n) 

Delayed goals:
	repair : unify_to_tent_if_ground_args(X{ic : 0 .. 3, repair : 1}, X)
	repair : unify_to_tent_if_ground_args(Y{ic : 0 .. 3, repair : 1}, Y)
	monitor_conflict(ic : (X{ic : 0 .. 3, repair : 1} #\= Y{ic : 0 .. 3, repair : 1}))
	monitor_tenable(X{ic : 0 .. 3, repair : 1}, s(yes))
	monitor_tenable(Y{ic : 0 .. 3, repair : 1}, s(yes))
	-(Y{ic : 0 .. 3, repair : 1}) + X{ic : 0 .. 3, repair : 1} #\= 0
Yes (0.00s cpu)


Any ideas?

Thanks,
Martin

--
Martin Michalowski, Ph.D.
Principal Research Scientist, Adventium Labs
martin.michalowski_at_adventiumlabs.com
http://www.adventiumlabs.com/staff/martin-michalowski