% vim: ts=4 sw=4 et ft=mercury
%
% Test taken from the XSB testsuite.
%
% Under local evaluation it results in:
% 318 variant call check/insert ops: 120 generators, 198 consumers.
% 120 answer check/insert ops: 120 unique inserts, 0 redundant.
%
% If d/4 is declared semidet, the program compiles with a warning that
% the determinism declaration of d/1 could be tighter, but when the
% program executes, it produces the right answer.
%
% If d/4 is declared nondet, the program compiles without warnings,
% but produces no answer when it executes.

:- module oota.

:- interface.

:- import_module io.

:- pred main(io::di, io::uo) is cc_multi.

:- implementation.

:- import_module benchmarking.
:- import_module int.
:- import_module list.
:- import_module maybe.
:- import_module std_util.
:- import_module string.
:- import_module unit.

:- pragma require_feature_set([memo]).

main(!IO) :-
    io.command_line_arguments(Args, !IO),
    ( if
        Args = [Arg],
        string.to_int(Arg, NumRepeatsPrime)
    then
        NumRepeats = NumRepeatsPrime
    else
        NumRepeats = 1
    ),
    benchmark_det(benchmark_d, unit, MaybeD, NumRepeats, Time),
    trace [compiletime(flag("benchmark_oota")), io(!S)] (
        io.format("time taken: %d ms\n", [i(Time)], !S)
    ),
    (
        MaybeD = yes(D),
        io.write_string("D = ", !IO),
        io.write_int(D, !IO),
        io.write_string("\n", !IO)
    ;
        MaybeD = no,
        io.write_string("failed\n", !IO)
    ).

:- pred benchmark_d(unit::in, maybe(int)::out) is det.

benchmark_d(unit, MaybeD) :-
    ( if d(D) then
        MaybeD = yes(D)
    else
        MaybeD = no
    ).

:- pred d(int::out) is semidet.

d(D) :-
    GC = 10, I = 11, J = 9,
    d(GC, I, J, D).

:- pred d(int::in, int::in, int::in, int::out) is semidet.
:- pragma memo(d/4).

d(GC, I, J, D) :-
    ( if I = 0, J = 0 then
        D = 0
    else if I = 0 then
        J1 = J - 1,
        d(GC, 0, J1, D1),
        D = D1 + GC
    else if J = 0 then
        I1 = I - 1,
        d(GC, I1, 0, D1),
        D = D1 + GC
    else
        I1 = I - 1,
        J1 = J - 1,
        ms(I, J, MS),
        d(GC, I1, J1, D1), D_MS = D1 + MS,
        d(GC, I1, J, D2), D_G1 = D2 + GC,
        d(GC, I, J1, D3), D_G2 = D3 + GC,
        min([D_MS, D_G1, D_G2], D)
    ).

:- pred min(list(int)::in, int::out) is semidet.

min(S, M) :-
    list.sort(S, [M | _]).

:- pred ms(int::in, int::in, int::out) is semidet.

ms(0, 0, 0).
ms(0, 1, 0).
ms(0, 2, 0).
ms(0, 3, 0).
ms(0, 4, 0).
ms(0, 5, 0).
ms(0, 6, 0).
ms(0, 7, 0).
ms(0, 8, 0).
ms(0, 9, 0).
ms(1, 0, 0).
ms(1, 1, 1).
ms(1, 2, 0).
ms(1, 3, 0).
ms(1, 4, 0).
ms(1, 5, 1).
ms(1, 6, 1).
ms(1, 7, 1).
ms(1, 8, 1).
ms(1, 9, 0).
ms(2, 0, 0).
ms(2, 1, 1).
ms(2, 2, 0).
ms(2, 3, 0).
ms(2, 4, 0).
ms(2, 5, 1).
ms(2, 6, 1).
ms(2, 7, 1).
ms(2, 8, 1).
ms(2, 9, 0).
ms(3, 0, 0).
ms(3, 1, 0).
ms(3, 2, 1).
ms(3, 3, 1).
ms(3, 4, 1).
ms(3, 5, 0).
ms(3, 6, 0).
ms(3, 7, 1).
ms(3, 8, 1).
ms(3, 9, 1).
ms(4, 0, 0).
ms(4, 1, 0).
ms(4, 2, 1).
ms(4, 3, 1).
ms(4, 4, 1).
ms(4, 5, 0).
ms(4, 6, 0).
ms(4, 7, 1).
ms(4, 8, 1).
ms(4, 9, 1).
ms(5, 0, 0).
ms(5, 1, 0).
ms(5, 2, 1).
ms(5, 3, 1).
ms(5, 4, 1).
ms(5, 5, 0).
ms(5, 6, 0).
ms(5, 7, 1).
ms(5, 8, 1).
ms(5, 9, 1).
ms(6, 0, 0).
ms(6, 1, 1).
ms(6, 2, 1).
ms(6, 3, 1).
ms(6, 4, 1).
ms(6, 5, 1).
ms(6, 6, 1).
ms(6, 7, 0).
ms(6, 8, 1).
ms(6, 9, 1).
ms(7, 0, 0).
ms(7, 1, 1).
ms(7, 2, 1).
ms(7, 3, 1).
ms(7, 4, 1).
ms(7, 5, 1).
ms(7, 6, 1).
ms(7, 7, 0).
ms(7, 8, 1).
ms(7, 9, 1).
ms(8, 0, 0).
ms(8, 1, 1).
ms(8, 2, 1).
ms(8, 3, 1).
ms(8, 4, 1).
ms(8, 5, 1).
ms(8, 6, 1).
ms(8, 7, 0).
ms(8, 8, 1).
ms(8, 9, 1).
ms(9, 0, 0).
ms(9, 1, 1).
ms(9, 2, 1).
ms(9, 3, 1).
ms(9, 4, 1).
ms(9, 5, 1).
ms(9, 6, 1).
ms(9, 7, 1).
ms(9, 8, 0).
ms(9, 9, 1).
ms(10, 0, 0).
ms(10, 1, 1).
ms(10, 2, 1).
ms(10, 3, 1).
ms(10, 4, 1).
ms(10, 5, 1).
ms(10, 6, 1).
ms(10, 7, 1).
ms(10, 8, 0).
ms(10, 9, 1).
ms(11, 0, 0).
ms(11, 1, 1).
ms(11, 2, 0).
ms(11, 3, 0).
ms(11, 4, 0).
ms(11, 5, 1).
ms(11, 6, 1).
ms(11, 7, 1).
ms(11, 8, 1).
ms(11, 9, 0).