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uni-m.cds-adv-prog/ex0.1/mandelbrot/mandelbrot.py
2019-10-30 09:02:41 +01:00

75 lines
1.8 KiB
Python

# The Computer Language Benchmarks Game
# https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
#
# contributed by Joerg Baumann
from contextlib import closing
from itertools import islice
from os import cpu_count
from sys import argv, stdout
def pixels(y, n, abs):
range7 = bytearray(range(7))
pixel_bits = bytearray(128 >> pos for pos in range(8))
c1 = 2. / float(n)
c0 = -1.5 + 1j * y * c1 - 1j
x = 0
while True:
pixel = 0
c = x * c1 + c0
for pixel_bit in pixel_bits:
z = c
for _ in range7:
for _ in range7:
z = z * z + c
if abs(z) >= 2.: break
else:
pixel += pixel_bit
c += c1
yield pixel
x += 8
def compute_row(p):
y, n = p
result = bytearray(islice(pixels(y, n, abs), (n + 7) // 8))
result[-1] &= 0xff << (8 - n % 8)
return y, result
def ordered_rows(rows, n):
order = [None] * n
i = 0
j = n
while i < len(order):
if j > 0:
row = next(rows)
order[row[0]] = row
j -= 1
if order[i]:
yield order[i]
order[i] = None
i += 1
def compute_rows(n, f):
row_jobs = ((y, n) for y in range(n))
if cpu_count() < 2:
yield from map(f, row_jobs)
else:
from multiprocessing import Pool
with Pool() as pool:
unordered_rows = pool.imap_unordered(f, row_jobs)
yield from ordered_rows(unordered_rows, n)
def mandelbrot(n):
write = stdout.buffer.write
with closing(compute_rows(n, compute_row)) as rows:
write("P4\n{0} {0}\n".format(n).encode())
for row in rows:
write(row[1])
if __name__ == '__main__':
mandelbrot(int(argv[1]))