The Computer Language
Benchmarks Game

binary-trees Erlang HiPE program

source code

% The Computer Language Benchmarks Game
% http://benchmarksgame.alioth.debian.org/
%
% contributed by Isaac Gouy (Erlang novice)

-module(binarytrees). 
-export([main/1]). 

-define(Min,4).

main([Arg]) ->
   N = list_to_integer(Arg),
   Max = lists:max([?Min+2,N]),

   Stretch = Max + 1,
   io:fwrite("stretch tree of depth ~w\t check: ~w~n", 
      [ Stretch, itemCheck(bottomUp(0,Stretch)) ]),

   LongLivedTree = bottomUp(0,Max),
   depthLoop(?Min,Max),

   io:fwrite("long lived tree of depth ~w\t check: ~w~n", 
      [ Max, itemCheck(LongLivedTree) ]),

   halt(0).


depthLoop(D,M) when D > M -> ok;
depthLoop(D,M) -> 
   N = 1 bsl (M-D + ?Min),
   io:fwrite("~w\t trees of depth ~w\t check: ~w~n", 
      [ 2*N, D, sumLoop(N,D,0) ]),
   depthLoop (D+2,M).

sumLoop(0,_,Sum) -> Sum;
sumLoop(N,D,Sum) -> 
   sumLoop(N-1,D, Sum + itemCheck(bottomUp(N,D)) + itemCheck(bottomUp(-1*N,D))).

bottomUp(I,0) -> {I, nil, nil};
bottomUp(I,D) -> {I, bottomUp(2*I-1,D-1), bottomUp(2*I,D-1)}.

itemCheck(nil) -> 0;
itemCheck({I,Left,Right}) -> 
   I + itemCheck(Left) - itemCheck(Right).
    

notes, command-line, and program output

NOTES:
32-bit Ubuntu one core
Erlang/OTP 19 [erts-8.0] [source] [async-threads:10] [hipe] [kernel-poll:false]



Fri, 24 Jun 2016 00:57:37 GMT

MAKE:
mv binarytrees.hipe binarytrees.erl
/usr/local/src/otp_src_19.0_nosmp/bin/erlc +native +"{hipe, [o3]}"  binarytrees.erl
rm binarytrees.erl
0.53s to complete and log all make actions

COMMAND LINE:
/usr/local/src/otp_src_19.0_nosmp/bin/erl -smp disable -noshell -run  binarytrees main 20

PROGRAM OUTPUT:
stretch tree of depth 21	 check: -1
2097152	 trees of depth 4	 check: -2097152
524288	 trees of depth 6	 check: -524288
131072	 trees of depth 8	 check: -131072
32768	 trees of depth 10	 check: -32768
8192	 trees of depth 12	 check: -8192
2048	 trees of depth 14	 check: -2048
512	 trees of depth 16	 check: -512
128	 trees of depth 18	 check: -128
32	 trees of depth 20	 check: -32
long lived tree of depth 20	 check: -1