我有这个程序可以列出一定范围内的质数。问题是数字越大，它变得越慢。我如何使用 numpy 来提高速度？如果不是 numpy，有没有其他方法可以加快计算速度？
from datetime import date
import time
import numpy as np
today = date.today()
lower = int(input("Starting Number: "))
upper = int(input("Ending Number: "))
print("Prime numbers between",lower,"and",upper,"are:")
with open("primenumbers.txt","a") as file:
file.write("\n")
file.write("{}".format(today))
file.write("\n")
start = time.time()
for num in range(lower,upper + 1):
if num > 1:
for i in range(2,num):
if (num % i) == 0:
break
else:
print(num)
with open("primenumbers.txt","a") as file:
file.write("\n")
file.write("{}".format(num))
end = time.time()
print(end - start)
我想更快地处理数据，请显示一些代码。
请您参考如下方法:
筛法是寻找素数的有效方法之一。我的回答灵感来自 this在 SO 中回答。对于 100 万，我得到了 timeit
16 ms ± 3.68 ms per loop (mean ± std. dev. of 7 runs, 100 loops each)
Numpy 实现
def first_n_prime_numbres(n):
s = np.arange(3, n, 2)
for m in range(3, int(n ** 0.5)+1, 2):
if s[(m-3)//2]:
s[(m*m-3)//2::m]=0
return np.r_[2, s[s>0]]
first_n_prime_numbres(100)
