started to develop STRIPS encoding variants

encodings/strips/strips-incremental.lp

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+#include <incmode>.
+
+#const _parallel = 0.
+
+% BASE PROGRAM
+
+% Define relevant fluents w.r.t. parallel mode
+
+diverge(A1,A2,X) :- active(A1), active(A2), A1 < A2, postcondition(A1,X,V),
+                    has_condition(A2,X,1), not postcondition(A2,X,V),
+                    _parallel = 1 : _parallel != 2.
+diverge(A1,A2)   :- diverge(A1,A2,X), _parallel = 1.
+
+exclude(A1,A2) :- diverge(A1,A2), precondition(A1,X,V),
+                  has_condition(A2,X,0), not precondition(A2,X,V).
+
+fluent(X,V) :- produce(X,V).
+fluent(X,V) :- persist(X,V).
+fluent(X,V) :- initialState(X,V), fluent(X).
+fluent(X,V) :- active(A), postcondition(A,X,V), fluent(X).
+fluent(X)   :- fluent(X,V).
+fluent(X)   :- diverge(A1,A2,X), not exclude(A1,A2).
+
+% Define unsubsumed mutexes
+
+mutex(G,V) :- mutexGroup(G), contains(G,X,V), fluent(X,V).
+mutex(G)   :- mutexGroup(G), #count{V : mutex(G,V)} > 1.
+
+% Define initial state
+
+holds(X,V,0) :- initialState(X,V), fluent(X).
+
+:- fluent(X), #count{V : holds(X,V,0) } > 1.
+:- mutex(G), #count{X,V : holds(X,V,0), contains(G,X,V) } > 1.
+
+% STEP PROGRAM
+
+#program step(t).
+
+% Generate successor state
+
+1 {holds(X,V,t) : fluent(X,V)} 1 :- fluent(X).
+
+:- mutex(G), #count{X,V : holds(X,V,t), contains(G,X,V) } > 1.
+
+change(X,t) :- holds(X,V,t), not holds(X,V,t-1).
+
+% Generate actions
+
+1 {occurs(A,t) : active(A)}.
+
+:- occurs(A,t), postcondition(A,X,V), fluent(X), not holds(X,V,t).
+
+effect(X,t) :- occurs(A,t), postcondition(A,X,V), fluent(X), not precondition(A,X,V).
+
+:- change(X,t), not effect(X,t).
+
+% Check w.r.t. parallel mode
+
+:- _parallel != 1, _parallel != 2, #count{A : occurs(A,t)} > 1.
+
+:- _parallel != 2, occurs(A,t), precondition(A,X,V), not holds(X,V,t-1).
+
+invariant(X,t) :- occurs(A,t), precondition(A,X,V), _parallel = 1,
+                  not has_condition(A,X,1).
+
+:- invariant(X,t), effect(X,t).
+
+singleton(X,t) :- occurs(A,t), precondition(A,X,V), _parallel = 1,
+                  has_condition(A,X,1), not postcondition(A,X,V).
+
+:- singleton(X,t), #count{A : occurs(A,t), postcondition(A,X,V), not precondition(A,X,V) } > 1.
+
+% CHECK PROGRAM
+
+#program check(t).
+
+% Check goal conditions
+
+:- query(t), goal(X,V), not holds(X,V,t).
+
+% DISPLAY PART
+
+#show occurs/2.