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Tip revision: 2a9b0a93091b9ef7350a94bb3d3f1c43725b7a8c authored by Georg Brandl on 05 March 2011, 13:54:19 UTC
Close 2.0 branch.
Close 2.0 branch.
Tip revision: 2a9b0a9
sortperf.py
"""Sort performance test.
See main() for command line syntax.
See tabulate() for output format.
"""
import sys
import time
import whrandom
import marshal
import tempfile
import operator
import os
td = tempfile.gettempdir()
def randrange(n):
"""Return a random shuffle of range(n)."""
fn = os.path.join(td, "rr%06d" % n)
try:
fp = open(fn, "rb")
except IOError:
result = []
for i in range(n):
result.append(whrandom.random())
try:
try:
fp = open(fn, "wb")
marshal.dump(result, fp)
fp.close()
fp = None
finally:
if fp:
try:
os.unlink(fn)
except os.error:
pass
except IOError, msg:
print "can't write", fn, ":", msg
else:
result = marshal.load(fp)
fp.close()
##assert len(result) == n
# Shuffle it a bit...
for i in range(10):
i = whrandom.randint(0, n-1)
temp = result[:i]
del result[:i]
temp.reverse()
result[len(result):] = temp
del temp
return result
def fl():
sys.stdout.flush()
def doit(L):
t0 = time.clock()
L.sort()
t1 = time.clock()
print "%6.2f" % (t1-t0),
fl()
def tabulate(r):
"""Tabulate sort speed for lists of various sizes.
The sizes are 2**i for i in r (the argument, a list).
The output displays i, 2**i, and the time to sort arrays of 2**i
floating point numbers with the following properties:
*sort: random data
\sort: descending data
/sort: ascending data
~sort: many duplicates
-sort: all equal
!sort: worst case scenario
"""
cases = ("*sort", "\\sort", "/sort", "~sort", "-sort", "!sort")
fmt = ("%2s %6s" + " %6s"*len(cases))
print fmt % (("i", "2**i") + cases)
for i in r:
n = 1<<i
L = randrange(n)
##assert len(L) == n
print "%2d %6d" % (i, n),
fl()
doit(L) # *sort
L.reverse()
doit(L) # \sort
doit(L) # /sort
if n > 4:
del L[4:]
L = L*(n/4)
L = map(lambda x: --x, L)
doit(L) # ~sort
del L
L = map(abs, [-0.5]*n)
doit(L) # -sort
L = range(n/2-1, -1, -1)
L[len(L):] = range(n/2)
doit(L) # !sort
print
def main():
"""Main program when invoked as a script.
One argument: tabulate a single row.
Two arguments: tabulate a range (inclusive).
Extra arguments are used to seed the random generator.
"""
import string
# default range (inclusive)
k1 = 15
k2 = 19
if sys.argv[1:]:
# one argument: single point
k1 = k2 = string.atoi(sys.argv[1])
if sys.argv[2:]:
# two arguments: specify range
k2 = string.atoi(sys.argv[2])
if sys.argv[3:]:
# derive random seed from remaining arguments
x, y, z = 0, 0, 0
for a in sys.argv[3:]:
h = hash(a)
h, d = divmod(h, 256)
h = h & 0xffffff
x = (x^h^d) & 255
h = h>>8
y = (y^h^d) & 255
h = h>>8
z = (z^h^d) & 255
whrandom.seed(x, y, z)
r = range(k1, k2+1) # include the end point
tabulate(r)
if __name__ == '__main__':
main()