Python Interpreters Benchmarks
x64 ArchLinux : AMD® Ryzen 7 4700U®

 performance measurements

Each table row shows performance measurements for this program with a particular command-line input value N.

 N  CPU secs Elapsed secs Memory KB Code B ≈ CPU Load
104.480.62102,152894  92% 90% 98% 89% 92% 84% 92% 90%

Read the ↓ make, command line, and program output logs to see how this program was run.

Read  benchmark to see what this program should do.


  source code

# The Computer Language Benchmarks Game
# contributed by Joerg Baumann
# many thanks to Oleg Mazurov for his helpful description

from sys import argv
from math import factorial
from multiprocessing import cpu_count, Pool
from itertools import islice, starmap

def permutations(n, start, size):
    p = bytearray(range(n))

    remainder = start
    for v in range(n - 1, 0, -1):
        rotation_count, remainder = divmod(remainder, factorial(v))
        for _ in range(rotation_count):
            p[:v], p[v] = p[1:v + 1], p[0]

    if size < 2:
        yield p[:]
        rotations = [(v, factorial(v)) for v in range(3, n)]
        for i in range(start + 2, start + size + 2, 2):
            yield p[:]
            p[0], p[1] = p[1], p[0]
            yield p[:]
            p[1], p[2] = p[2], p[1]
            for v, modulo in rotations:
                if i % modulo != 0:
                p[:v], p[v] = p[1:v + 1], p[0]

def alternating_flips_generator(n, start, size):
    maximum_flips = 0
    alternating_factor = 1
    for permutation in permutations(n, start, size):
        first = permutation[0]
        if first:
            flips_count = 1
            while True:
                permutation[:first + 1] = permutation[first::-1]
                first = permutation[0]
                if not first: break
                flips_count += 1
            if maximum_flips < flips_count:
                maximum_flips = flips_count
            yield flips_count * alternating_factor
            yield 0
        alternating_factor = -alternating_factor
    yield maximum_flips

def task(n, start, size):
    alternating_flips = alternating_flips_generator(n, start, size)
    return sum(islice(alternating_flips, size)), next(alternating_flips)

def fannkuch(n):
    assert(n > 0)

    task_count = cpu_count()
    total = factorial(n)
    task_size = (total + task_count - 1) // task_count

    if task_size < 20000:
        task_size = total
        task_count = 1

    assert(task_size % 2 == 0)

    task_args = [(n, i * task_size, task_size) for i in range(task_count)]

    if task_count > 1:
        with Pool() as pool:
            checksums, maximums = zip(*pool.starmap(task, task_args))
        checksums, maximums = zip(*starmap(task, task_args))

    checksum, maximum = sum(checksums), max(maximums)
    print("{0}\nPfannkuchen({1}) = {2}".format(checksum, n, maximum))

if __name__ == "__main__":

 make, command-line, and program output logs

 Sun, 23 Apr 2023 09:08:20 GMT

make[1]: Vstupuje se do adresáře „/home/dundee/work/pybenchmarks/bencher/tmp/fannkuchredux/tmp“
nuitka3 --remove-output fannkuchredux.nuitka-3.nuitka
Nuitka-Options:INFO: Used command line options: --remove-output fannkuchredux.nuitka-3.nuitka
Nuitka-Options:WARNING: You did not specify to follow or include anything but main program. Check options and make sure that is intended.
Nuitka:INFO: Starting Python compilation with Nuitka '1.5' on Python '3.10' commercial grade 'not installed'.
Nuitka-Plugins:INFO: multiprocessing: Injecting pre-module load code for module 'multiprocessing':
Nuitka-Plugins:INFO: multiprocessing:     Monkey patching "multiprocessing" load environment.
Nuitka-Plugins:INFO: multiprocessing: Injecting post-module load code for module 'multiprocessing':
Nuitka-Plugins:INFO: multiprocessing:     Monkey patching "multiprocessing" for compiled methods.
Nuitka:INFO: Completed Python level compilation and optimization.
Nuitka:INFO: Generating source code for C backend compiler.
Nuitka:INFO: Running data composer tool for optimal constant value handling.
Nuitka:INFO: Running C compilation via Scons.
Nuitka-Scons:INFO: Backend C compiler: gcc (gcc).
Nuitka-Scons:INFO: Backend linking program with 10 files (no progress information available).
Nuitka-Scons:WARNING: You are not using ccache.
Nuitka:INFO: Removing build directory ''.
Nuitka:INFO: Successfully created 'fannkuchredux.nuitka-3.nuitka.bin'.
cp fannkuchredux.nuitka-3.nuitka.bin fannkuchredux.nuitka-3.nuitka_run
make[1]: Opouští se adresář „/home/dundee/work/pybenchmarks/bencher/tmp/fannkuchredux/tmp“
19.35s to complete and log all make actions

 ./fannkuchredux.nuitka-3.nuitka_run 10

Pfannkuchen(10) = 38

Revised BSD license

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