2014-10-27 20:10:17 -04:00

58 lines
1.4 KiB
Python
Executable File

#!/usr/bin/python
import math
import random
def finding_prime(number):
''' find whether a number is prime in a simple way'''
num = abs(number)
if num < 4 : return True
for x in range(2, num):
if num % x == 0:
return False
return True
def finding_prime_sqrt(number):
''' find whether a number is prime as soon as it rejects all candidates up to sqrt(n) '''
num = abs(number)
if num < 4 : return True
for x in range(2, int(math.sqrt(num)) + 1):
if number % x == 0:
return False
return True
def finding_prime_fermat(number):
''' find whether a number is prime with Fermat's theorem, using probabilistic tests '''
if number <= 102:
for a in range(2, number):
if pow(a, number- 1, number) != 1:
return False
return True
else:
for i in range(100):
a = random.randint(2, number - 1)
if pow(a, number - 1, number) != 1:
return False
return True
def test_finding_prime():
number1 = 17
number2 = 20
assert(finding_prime(number1) == True)
assert(finding_prime(number2) == False)
assert(finding_prime_sqrt(number1) == True)
assert(finding_prime_sqrt(number2) == False)
assert(finding_prime_fermat(number1) == True)
assert(finding_prime_fermat(number2) == False)
print('Tests passed!')
if __name__ == '__main__':
test_finding_prime()