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yap-6.3/JIT/examples/binary_trees.pl

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% ----------------------------------------------------------------------
% The Computer Language Benchmarks Game
% http://shootout.alioth.debian.org/
%
% Contributed by Anthony Borla
% Modified to run with YAP by Glendon Holst
% ----------------------------------------------------------------------
:- yap_flag(unknown,error).
:- initialization(main).
main :-
unix( argv([H|_]) ), number_atom(N,H),
MIN_DEPTH is 4, set_limits(N, MIN_DEPTH, MAX_DEPTH, STRETCH_DEPTH),
bottom_up_tree(0, STRETCH_DEPTH, ST),
check_tree(ST, ITS),
format('stretch tree of depth ~w\t check: ~w~n', [STRETCH_DEPTH, ITS]),
bottom_up_tree(0, MAX_DEPTH, LLT),
descend_trees(MIN_DEPTH, MIN_DEPTH, MAX_DEPTH),
check_tree(LLT, ITL),
format('long lived tree of depth ~w\t check: ~w~n', [MAX_DEPTH, ITL]),
statistics,
statistics_jit.
% ------------------------------- %
set_limits(N, MinDepth, MaxDepth, StretchDepth) :-
MinDepth1 is MinDepth + 2,
(MinDepth1 > N -> MaxDepth is MinDepth1 ; MaxDepth is N),
StretchDepth is MaxDepth + 1.
% ------------------------------- %
descend_trees(CurrentDepth, MinDepth, MaxDepth) :-
(
CurrentDepth =< MaxDepth ->
N is integer(2 ** (MaxDepth - CurrentDepth + MinDepth)), Iterations is 2 * N,
sum_trees(N, CurrentDepth, 0, Sum),
format('~w\t trees of depth ~w\t check: ~w~n', [Iterations, CurrentDepth, Sum]),
NewDepth is CurrentDepth + 2, !, descend_trees(NewDepth, MinDepth, MaxDepth)
;
true
).
% ------------- %
sum_trees(0, _, AccSum, AccSum) :- !.
sum_trees(N, CurrentDepth, AccSum, Sum) :-
bottom_up_tree(N, CurrentDepth, TreeLeft),
Nneg is -1 * N, bottom_up_tree(Nneg, CurrentDepth, TreeRight),
check_tree(TreeLeft, ItemLeft), check_tree(TreeRight, ItemRight),
AccSum1 is AccSum + ItemLeft + ItemRight,
N1 is N - 1, !, sum_trees(N1, CurrentDepth, AccSum1, Sum).
% ------------------------------- %
make_tree(Item, Left, Right, tree(Item, Left, Right)).
% ------------- %
bottom_up_tree(Item, 0, tree(Item, nil, nil)) :- !.
bottom_up_tree(Item, Depth, Tree) :-
ItemLeft is 2 * Item - 1, DepthLeft is Depth - 1,
bottom_up_tree(ItemLeft, DepthLeft, TreeLeft),
ItemRight is 2 * Item, DepthRight is Depth - 1,
bottom_up_tree(ItemRight, DepthRight, TreeRight),
make_tree(Item, TreeLeft, TreeRight, Tree).
% ------------- %
check_tree(tree(Item, nil, _), Item) :- !.
check_tree(tree(Item, _, nil), Item) :- !.
check_tree(tree(Item, Left, Right), ItemNew) :-
check_tree(Left, ItemLeft),
check_tree(Right, ItemRight),
ItemNew is Item + ItemLeft - ItemRight.
% ------------------------------- %