25 lines
515 B
Plaintext
25 lines
515 B
Plaintext
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%
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%% 991202 Slim Abdennadher, LMU
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%%
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%% ported to hProlog by Tom Schrijvers
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:- module(fib,[]).
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:- use_module(library(chr)).
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:- constraints fib/2.
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%% fib(N,M) is true if M is the Nth Fibonacci number.
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%% Top-down Evaluation with Tabulation
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fib(N,M1), fib(N,M2) <=> M1 = M2, fib(N,M1).
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fib(0,M) ==> M = 1.
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fib(1,M) ==> M = 1.
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fib(N,M) ==> N > 1 | N1 is N-1, fib(N1,M1), N2 is N-2, fib(N2,M2), M is M1 + M2.
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