51 lines
1.8 KiB
Plaintext
51 lines
1.8 KiB
Plaintext
% Constant '_closure' to (de)activate analysis of potentially relevant actions
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% - value '1': forward chaining of effects w.r.t. initial variable values
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% - value '2': backward regression of effects w.r.t. goal variable values
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% - value '3': both forward chaining and backward regression of effects
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% - otherwise: off
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#const _closure = 3.
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% BASE PROGRAM
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% Check feature requirements
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:- requires(feature(actionCosts)).
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:- requires(feature(axiomRules)).
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:- requires(feature(conditionalEffects)).
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% Basic redundancy check for actions
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postcondition(A,X,V) :- postcondition(A,E,X,V).
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has_condition(A,X,0) :- action(A), precondition(A,X,V).
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has_condition(A,X,1) :- action(A), postcondition(A,X,V).
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inconsistent(A) :- has_condition(A,X,P),
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#count{V : precondition(A,X,V), P = 0;
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V : postcondition(A,X,V), P = 1} > 1.
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consistent(A) :- action(A), not inconsistent(A).
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irredundant(A) :- consistent(A), postcondition(A,X,V), not precondition(A,X,V).
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% Forward chaining of effects w.r.t. initial variable values
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feasible(X,V) :- initialState(X,V).
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feasible(X,V) :- possible(A), postcondition(A,X,V).
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possible(A) :- irredundant(A), feasible(X,V) : precondition(A,X,V).
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possible(A) :- irredundant(A), _closure != 1, _closure != 3.
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:- goal(X,V), not feasible(X,V).
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% Backward regression of effects w.r.t. goal variable values
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produce(X,V) :- goal(X,V), not initialState(X,V).
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produce(X,V) :- active(A), precondition(A,X,V), not initialState(X,V).
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produce(X,V) :- persist(X,V), active(A), has_condition(A,X,1), not postcondition(A,X,V).
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persist(X,V) :- goal(X,V), initialState(X,V).
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persist(X,V) :- active(A), precondition(A,X,V), initialState(X,V).
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active(A) :- possible(A), postcondition(A,X,V), produce(X,V).
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active(A) :- possible(A), _closure != 2, _closure != 3.
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