49 lines
766 B
Plaintext
49 lines
766 B
Plaintext
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:- object(_ ** _,
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implements(symdiffp)).
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:- info([
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authors is 'Paulo Moura',
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version is 1.0,
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date is 1999/12/29,
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parnames is ['Expression', 'Power'],
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comment is 'Symbolic differentiation and simplification of **/2 expressions.',
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source is 'Example based on the Clocksin and Mellish Prolog book.']).
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diff(Diff) :-
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this(X ** Y),
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once(diff(X, Y, Diff)).
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diff(X, Y, Y * X ** Y2 * DX) :-
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integer(Y),
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Y2 is Y - 1,
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X::diff(DX).
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diff(X, Y, Y * X ** Y2 * DX) :-
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Y2 = Y - 1,
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X::diff(DX).
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simplify(S) :-
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this(X ** Y),
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once(simplify(X, Y, S)).
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simplify(_, 0, 1).
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simplify(X, 1, X).
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simplify(X, Y, S ** Y) :-
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integer(Y),
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X::simplify(S).
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simplify(X, Y, SX ** SY) :-
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X::simplify(SX),
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Y::simplify(SY).
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:- end_object.
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