143 lines
3.5 KiB
Python
143 lines
3.5 KiB
Python
"""Sort performance test.
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See main() for command line syntax.
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See tabulate() for output format.
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"""
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import sys
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import time
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import whrandom
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import marshal
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import tempfile
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import operator
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import os
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td = tempfile.gettempdir()
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def randrange(n):
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"""Return a random shuffle of range(n)."""
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fn = os.path.join(td, "rr%06d" % n)
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try:
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fp = open(fn, "rb")
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except IOError:
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result = []
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for i in range(n):
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result.append(whrandom.random())
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try:
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try:
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fp = open(fn, "wb")
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marshal.dump(result, fp)
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fp.close()
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fp = None
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finally:
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if fp:
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try:
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os.unlink(fn)
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except os.error:
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pass
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except IOError, msg:
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print "can't write", fn, ":", msg
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else:
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result = marshal.load(fp)
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fp.close()
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##assert len(result) == n
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# Shuffle it a bit...
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for i in range(10):
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i = whrandom.randint(0, n-1)
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temp = result[:i]
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del result[:i]
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temp.reverse()
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result[len(result):] = temp
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del temp
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return result
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def fl():
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sys.stdout.flush()
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def doit(L):
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t0 = time.clock()
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L.sort()
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t1 = time.clock()
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print "%6.2f" % (t1-t0),
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fl()
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def tabulate(r):
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"""Tabulate sort speed for lists of various sizes.
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The sizes are 2**i for i in r (the argument, a list).
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The output displays i, 2**i, and the time to sort arrays of 2**i
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floating point numbers with the following properties:
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*sort: random data
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\sort: descending data
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/sort: ascending data
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~sort: many duplicates
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-sort: all equal
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!sort: worst case scenario
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"""
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cases = ("*sort", "\\sort", "/sort", "~sort", "-sort", "!sort")
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fmt = ("%2s %6s" + " %6s"*len(cases))
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print fmt % (("i", "2**i") + cases)
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for i in r:
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n = 1<<i
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L = randrange(n)
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##assert len(L) == n
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print "%2d %6d" % (i, n),
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fl()
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doit(L) # *sort
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L.reverse()
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doit(L) # \sort
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doit(L) # /sort
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if n > 4:
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del L[4:]
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L = L*(n/4)
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L = map(lambda x: --x, L)
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doit(L) # ~sort
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del L
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L = map(abs, [-0.5]*n)
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doit(L) # -sort
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L = range(n/2-1, -1, -1)
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L[len(L):] = range(n/2)
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doit(L) # !sort
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print
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def main():
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"""Main program when invoked as a script.
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One argument: tabulate a single row.
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Two arguments: tabulate a range (inclusive).
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Extra arguments are used to seed the random generator.
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"""
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import string
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# default range (inclusive)
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k1 = 15
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k2 = 19
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if sys.argv[1:]:
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# one argument: single point
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k1 = k2 = string.atoi(sys.argv[1])
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if sys.argv[2:]:
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# two arguments: specify range
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k2 = string.atoi(sys.argv[2])
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if sys.argv[3:]:
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# derive random seed from remaining arguments
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x, y, z = 0, 0, 0
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for a in sys.argv[3:]:
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h = hash(a)
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h, d = divmod(h, 256)
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h = h & 0xffffff
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x = (x^h^d) & 255
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h = h>>8
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y = (y^h^d) & 255
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h = h>>8
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z = (z^h^d) & 255
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whrandom.seed(x, y, z)
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r = range(k1, k2+1) # include the end point
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tabulate(r)
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if __name__ == '__main__':
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main()
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