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