43 lines
928 B
Plaintext
43 lines
928 B
Plaintext
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%%
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%% 16 June 2003 Bart Demoen, Tom Schrijvers, K.U.Leuven
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%%
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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:- module(fibonacci,[main/0,main/1]).
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:- use_module(library(chr)).
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:- chr_constraint fibonacci/2.
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%% fibonacci(N,M) is true iff M is the Nth Fibonacci number.
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%% Top-down Evaluation with effective Tabulation
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%% Contrary to the version in the SICStus manual, this one does "true"
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%% tabulation
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fibonacci(N,M1) # ID \ fibonacci(N,M2) <=> var(M2) | M1 = M2 pragma passive(ID).
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fibonacci(0,M) ==> M = 1.
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fibonacci(1,M) ==> M = 1.
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fibonacci(N,M) ==>
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N > 1 |
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N1 is N-1,
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fibonacci(N1,M1),
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N2 is N-2,
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fibonacci(N2,M2),
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M is M1 + M2.
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main :-
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main(2000).
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main(N):-
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cputime(X),
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fibonacci(N,_),
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cputime( Now),
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Time is Now-X,
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write(bench(fibonacci ,N,Time, 0, hprolog)),write('.'), nl.
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