Prime Number Finder - Optimization

I'm trying to build a prime number finder that would work as fast as possible. This is the def function that is included in the program. I'm having problems with just one detail, w

Solution 1:

As pointed out in the comment above, python2 performs integer division so 1/2 == 0

• You can write your root as:

  x**0.5
  

• or using math.sqrt:

  math.sqrt(x)
  

The naive primality test can be implemented like this:

defis_prime(n):
    if n<=1: returnFalseif n<=3: returnTrueifnot n%2ornot n%3: returnFalse
    i=5while i*i<=n:
        if n%i==0: returnFalse
        i+=2if n%i==0: returnFalse
        i+=4returnTrue