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84 lines
2.0 KiB
Mathematica
84 lines
2.0 KiB
Mathematica
% vim: ts=4 sw=4 et ft=mercury
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:- module fib_uint32.
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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 int.
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:- import_module uint32.
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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(20u32, !IO).
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:- pred perform_trials(uint32::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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trace [compiletime(flag("progress")), io(!S)] (
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io.write_string("trial ", !S),
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io.write_uint32(N, !S),
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io.write_string(": ", !S),
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io.write_int(Time, !S),
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io.write_string("ms nonmemoed vs ", !S),
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io.write_int(MTime, !S),
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io.write_string("ms memoed\n", !S)
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),
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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 + 3u32, !IO)
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).
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:- pred trial(uint32::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(uint32::in, uint32::out) is det.
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fib(N, F) :-
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( if N < 2u32 then
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F = 1u32
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else
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fib(N - 1u32, F1),
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fib(N - 2u32, F2),
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F = F1 + F2
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).
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:- pred mfib(uint32::in, uint32::out) is det.
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:- pragma memo(mfib/2).
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mfib(N, F) :-
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( if N < 2u32 then
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F = 1u32
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else
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mfib(N - 1u32, F1),
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mfib(N - 2u32, F2),
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F = F1 + F2
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).
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