Różnice między wybraną wersją a wersją aktualną.
|
pl:prolog:pllib:generalization [2019/06/27 15:50] |
pl:prolog:pllib:generalization [2019/06/27 15:50] (aktualna) |
||
|---|---|---|---|
| Linia 1: | Linia 1: | ||
| + | ====== Generalization ====== | ||
| + | {{tag>rules}} | ||
| + | ===== Description ===== | ||
| + | Explanation-based generalization. | ||
| + | |||
| + | **Source**: PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7. | ||
| + | ===== Download ===== | ||
| + | Program source code: {{generalization.pl}} | ||
| + | ===== Listing ===== | ||
| + | <code prolog> | ||
| + | % Figure 23.4 Explanation-based generalization. | ||
| + | |||
| + | :- op( 900, fy, not). | ||
| + | |||
| + | % not Goal): negation as failure; | ||
| + | % Note: This is often available as a built-in predicate, | ||
| + | % often written as prefix operator "\+", e.g. \+ likes(mary,snakes) | ||
| + | |||
| + | not Goal :- | ||
| + | Goal, !, fail | ||
| + | ; | ||
| + | true. | ||
| + | |||
| + | % ebg( Goal, GeneralizedGoal, SufficientCondition) if | ||
| + | % SufficientCondition in terms of operational predicates | ||
| + | % guarantees that generalization of Goal, GeneralizedGoal, is true. | ||
| + | % GeneralizedGoal must not be a variable | ||
| + | |||
| + | ebg( true, true, true) :- !. | ||
| + | |||
| + | ebg( Goal, GenGoal, GenGoal) :- | ||
| + | operational( GenGoal), | ||
| + | call( Goal). | ||
| + | |||
| + | ebg( (Goal1,Goal2), (Gen1,Gen2), Cond) :- !, | ||
| + | ebg( Goal1, Gen1, Cond1), | ||
| + | ebg( Goal2, Gen2, Cond2), | ||
| + | and( Cond1, Cond2, Cond). % Cond = (Cond1,Cond2) simplified | ||
| + | |||
| + | ebg( Goal, GenGoal, Cond) :- | ||
| + | not operational( Goal), | ||
| + | clause( GenGoal, GenBody), | ||
| + | copy_term( (GenGoal,GenBody), (Goal,Body)), % Fresh copy of (GenGoal,GenBody) | ||
| + | ebg( Body, GenBody, Cond). | ||
| + | |||
| + | % and( Cond1, Cond2, Cond) if | ||
| + | % Cond is (possibly simplified) conjunction of Cond1 and Cond2 | ||
| + | |||
| + | and( true, Cond, Cond) :- !. % (true and Cond) <==> Cond | ||
| + | |||
| + | and( Cond, true, Cond) :- !. % (Cond and true) <==> Cond | ||
| + | |||
| + | and( Cond1, Cond2, ( Cond1, Cond2)). | ||
| + | </code> | ||
| + | ===== Comments ===== | ||
