你加快以下代码的速度有多冷，能够做100多个人吗？
""" Random Walker """
import numpy as np
import scipy as sp
import random as rd
import time
def procedure():
time.sleep(2.5)
t0C = time.clock()
t0 = time.time()
"""Definitions"""
def ifilterfalse(predicate, iterable):
# ifilterfalse(lambda x: x%2, range(10)) --> 0 2 4 6 8
if predicate is None:
predicate = bool
for x in iterable:
if not predicate(x):
yield x
def unique_everseen(iterable, key=None):
"List unique elements, preserving order. Remember all elements ever seen."
# unique_everseen('AAAABBBCCDAABBB') --> A B C D
# unique_everseen('ABBCcAD', str.lower) --> A B C D
seen = set()
seen_add = seen.add
if key is None:
for element in ifilterfalse(seen.__contains__, iterable):
seen_add(element)
yield element
else:
for element in iterable:
k = key(element)
if k not in seen:
seen_add(k)
yield element
"""Creating the Random Walk"""
n=int(input('Number of Individuals at Table: '))
iters=10000
final=np.zeros(n)
total=0
for j in xrange(iters):
d=np.array([0])
i=0
while i<1:
new=d[len(d)-1]+rd.choice([-1,1])
if new<0:
new+=n
elif new>=n:
new-=n
d=np.append(d,new)
dshort=list(unique_everseen(d))
if len(dshort)>=n:
i=1
last=dshort[len(dshort)-1]
length=len(d)
final[last]+=1
total+=length
final=np.round(final/iters,4)
total=round(total/iters,3)
"""Writing To A File"""
print (40 * '-')
print (" ")
print (" Percentages: ")
print (" ")
print (" S#:"+" S#:".join(map(str,range(n))))
print (" "+"% ".join(map(str,final))+"%")
print (" ")
print (" Average Number of Passes of Plate: {}".format(total))
print (" ")
print (40 * '-')
# measure process time
print time.clock() - t0C, "seconds process time"
# measure wall time
print time.time() - t0, "seconds wall time"
if __name__ == "__main__":
procedure()
现在对于10个人的情况来说，时间是：
5.877529秒处理时间
12.9134569168秒壁时间
问题是当个人数量（100,1000）增加时代码太慢，有什么建议吗？
答案 0 :(得分：2)
问题在于unique_everseen在连续执行中几乎完成了相同的工作，耗费了太多时间。这是一个简化版本，删除unique_everseen函数和d列表并直接在主循环和seen var中使用last集来保留最后一项：
""" Random Walker """
import random as rd
import time
def procedure():
n = int(input('Number of Individuals at Table: '))
t0C = time.clock()
t0 = time.time()
iters = 10000
final = [0] * n
total = 0
for j in xrange(iters):
last = 0
count = 1
seen = set([0])
while len(seen) < n:
count += 1;
new = last + rd.choice([-1, 1])
if new < 0:
new += n
elif new >= n:
new -= n
seen.add(new)
last = new
final[last] += 1
total += count
final = [round(float(f) / iters, 4) for f in final]
total = round(float(total) / iters, 3)
"""Writing To A File"""
print(40 * '-')
print(" ")
print(" Percentages: ")
print(" ")
print(" S#:" + " S#:".join(map(str, range(n))))
print(" " + "% ".join(map(str, final)) + "%")
print(" ")
print(" Average Number of Passes of Plate: {}".format(total))
print(" ")
print(40 * '-')
# measure process time
print time.clock() - t0C, "seconds process time"
# measure wall time
print time.time() - t0, "seconds wall time"
if __name__ == "__main__":
procedure()
请注意，删除numpy依赖项允许脚本使用pypy
某些结果（以小节为单位）