def pfactors(num, l=[]):
if (num == 1): return [1]
if len(l) == 0: l = get_list()
loc, found = search.binary_low(l, num)
e = l[-1]
# If number is in list
# It means the number is prime
# Hence it is the only prime factor
if (found): return [num]
# Get all primes below num
ll = primes(num, l)
return [n for n in ll if(num % n == 0)]
def primes(num, l=[]):
if len(l) == 0: l = get_list()
# Check to see if a sublist can be created
e = l[-1]
if (num < e):
res = search.binary_low(l, num)
return l[:res[0]+1]
e = 6*(ceil(e/6))
lim = num + 1
# Extend the current list
for n in range(e, lim, 6):
m = n - 1
if isprime(m, l): l.append(m)
m = n + 1
if isprime(m, l): l.append(m)
# Save to pickle
set_list(l)
return l
