mirror of
https://github.com/Mercury-Language/mercury.git
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84 lines
2.0 KiB
Mathematica
84 lines
2.0 KiB
Mathematica
%---------------------------------------------------------------------------%
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% vim: ts=4 sw=4 et ft=mercury
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%---------------------------------------------------------------------------%
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:- module fib_float.
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:- interface.
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:- import_module io.
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:- pred main(io::di, io::uo) is cc_multi.
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:- implementation.
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:- import_module benchmarking.
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:- import_module float.
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:- import_module int.
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:- import_module require.
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:- pragma require_feature_set([memo]).
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main(!IO) :-
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perform_trials(20.0, !IO).
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:- pred perform_trials(float::in, io::di, io::uo) is cc_multi.
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perform_trials(N, !IO) :-
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trial(N, Time, MTime),
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% io.write_float(N, !IO),
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% io.write_string(": ", !IO),
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% io.write_int(Time, !IO),
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% io.write_string("ms vs ", !IO),
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% io.write_int(MTime, !IO),
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% io.write_string("ms\n", !IO),
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( if
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(
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Time > 10 * MTime,
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MTime > 0 % untabled takes ten times as long
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;
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Time > 100, % untabled takes at least 100 ms
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MTime < 1 % while tabled takes at most 1 ms
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)
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then
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io.write_string("tabling works\n", !IO)
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else if
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Time > 10000 % untabled takes at least 10 seconds
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then
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io.write_string("tabling does not appear to work\n", !IO)
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else
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% We couldn't get a measurable result with N,
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% and it looks like we can afford a bigger trial
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perform_trials(N + 3.0, !IO)
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).
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:- pred trial(float::in, int::out, int::out) is cc_multi.
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trial(N, Time, MTime) :-
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benchmark_det(fib, N, Res, 1, Time),
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benchmark_det(mfib, N, MRes, 1, MTime),
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require(unify(Res, MRes), "tabling produces wrong answer").
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:- pred fib(float::in, float::out) is det.
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fib(N, F) :-
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( if N < 2.0 then
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F = 1.0
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else
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fib(N - 1.0, F1),
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fib(N - 2.0, F2),
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F = F1 + F2
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).
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:- pred mfib(float::in, float::out) is det.
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:- pragma memo(mfib/2).
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mfib(N, F) :-
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( if N < 2.0 then
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F = 1.0
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else
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mfib(N - 1.0, F1),
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mfib(N - 2.0, F2),
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F = F1 + F2
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).
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