python-jit(提高代码运行速度)

#coding:utf-8
import time
from numba import jit
import pandas as pd
# from numba import autojit
# @autojit                   #能对所有类型的参数进行运算

@jit                        #即时编译，产生的函数只能对指定类型的参数进行运算
def foo():
   i = 0
   for a in range(200000000):
      i += 1

@jit                                #可同时使用多个@jit
def foo2():
   for a in range(200000000):
      continue

# if __name__ == '__main__':
#  start = time()
#  foo()
#  end = time()
#  shi = end-start
#  start2 = time()
#  foo2()
#  end2 = time()
#  shi2 = end2-start2
#  print("foo()总耗时：%s秒" % shi)    # 7.158811807632446秒
#  print("foo2()总耗时：%s秒" % shi2)  # 3.4891695976257324秒

# 在jit装饰器的函数中，不可以使用第三方的packpage
# @jit
# def time_com(i):
#  cum = 0
#  for test in range(i):
#     for ind in range(i):
#        cum += (test * ind) % 3
#  return cum
# t1 = time.clock()
# df = pd.DataFrame()
# for i in range(1000):
#  print(time_com(i))
# t2 = time.clock()
#
# print("run time:%f s" % (t2 - t1)) # run time:24.704479 s

@jit
def fib(n):
   if n <= 2:
      return 1
   else:
      return fib(n-1) + fib(n-2)
start = time.clock()
print(fib(30))
end = time.clock()
print("user time:{} s".format(end-start))