The Computer Language
Benchmarks Game

binary-trees Python 3 program

source code

# The Computer Language Benchmarks Game
# http://benchmarksgame.alioth.debian.org/
#
# contributed by Antoine Pitrou
# modified by Dominique Wahli and Daniel Nanz
# modified by Joerg Baumann

import sys
import multiprocessing as mp


def make_tree(d):

    if d > 0:
        d -= 1
        return (make_tree(d), make_tree(d))
    return (None, None)


def check_tree(node):

    (l, r) = node
    if l is None:
        return 1
    else:
        return 1 + check_tree(l) + check_tree(r)


def make_check(itde, make=make_tree, check=check_tree):

    i, d = itde
    return check(make(d))


def get_argchunks(i, d, chunksize=5000):

    assert chunksize % 2 == 0
    chunk = []
    for k in range(1, i + 1):
        chunk.extend([(k, d)])
        if len(chunk) == chunksize:
            yield chunk
            chunk = []
    if len(chunk) > 0:
        yield chunk


def main(n, min_depth=4):

    max_depth = max(min_depth + 2, n)
    stretch_depth = max_depth + 1
    if mp.cpu_count() > 1:
        pool = mp.Pool()
        chunkmap = pool.map
    else:
        chunkmap = map

    print('stretch tree of depth {0}\t check: {1}'.format(
          stretch_depth, make_check((0, stretch_depth))))

    long_lived_tree = make_tree(max_depth)

    mmd = max_depth + min_depth
    for d in range(min_depth, stretch_depth, 2):
        i = 2 ** (mmd - d)
        cs = 0
        for argchunk in get_argchunks(i,d):
            cs += sum(chunkmap(make_check, argchunk))
        print('{0}\t trees of depth {1}\t check: {2}'.format(i, d, cs))

    print('long lived tree of depth {0}\t check: {1}'.format(
          max_depth, check_tree(long_lived_tree)))


if __name__ == '__main__':
    main(int(sys.argv[1]))
    

notes, command-line, and program output

NOTES:
64-bit Ubuntu quad core
Python 3.6.1 (default, Apr 18 2017, 10:33:41)
[GCC 6.3.0 20170406]
--enable-optimizations --with-lto
make profile-opt


Tue, 18 Apr 2017 19:42:12 GMT

MAKE:
mv binarytrees.python3 binarytrees.py
0.02s to complete and log all make actions

COMMAND LINE:
/usr/local/src/Python-3.6.1/bin/python3.6 -OO binarytrees.py 21

PROGRAM OUTPUT:
stretch tree of depth 22	 check: 8388607
2097152	 trees of depth 4	 check: 65011712
524288	 trees of depth 6	 check: 66584576
131072	 trees of depth 8	 check: 66977792
32768	 trees of depth 10	 check: 67076096
8192	 trees of depth 12	 check: 67100672
2048	 trees of depth 14	 check: 67106816
512	 trees of depth 16	 check: 67108352
128	 trees of depth 18	 check: 67108736
32	 trees of depth 20	 check: 67108832
long lived tree of depth 21	 check: 4194303