sieve_wim_numpy_jit.py

# wim's slicing idea from stackoverflow.com
# using numpy arrays - less memory
# JIT compiler jit nopeuttaa kun n > miljoona
# Juhani Kaukoranta 24.3.2019
import time
import numpy as np
from numba import jit
@jit
def primes(n):
    r = np.ones(n,dtype=bool)
    r[0] = r[1] = False
    r[4::2] = False
    for i in range(3,int(1 + np.sqrt(n)+1),2):
        if r[i]:
            r[i*i::2*i] = False
    return (np.flatnonzero(r))
high = int(input("Anna kokonaisluku, jota pienemmät alkuluvut lasketaan "))
time0 = time.perf_counter()
alkuluvut = primes(high)
time1 = time.perf_counter()
print("Laskenta-aika = ",time1-time0," sekuntia")
print("alkuluvut = ",alkuluvut)
print("alkulukuja oli ",len(alkuluvut)," kpl")