twister.py

import random
import os

# Create a length 624 list to store the state of the generator
MT = [0 for i in range(624)]
index = 0

# To get last 32 bits
bitmask_1 = (2 ** 32) - 1

# To get 32. bit
bitmask_2 = 2 ** 31

# To get last 31 bits
bitmask_3 = (2 ** 31) - 1

def initialize_generator(seed):
    "Initialize the generator from a seed"
    global MT
    global bitmask_1
    MT[0] = seed
    for i in range(1,624):
        MT[i] = ((1812433253 * MT[i-1]) ^ ((MT[i-1] >> 30) + i)) & bitmask_1


def extract_number():
    """
    Extract a tempered pseudorandom number based on the index-th value,
    calling generate_numbers() every 624 numbers
    """
    global index
    global MT
    if index == 0:
        generate_numbers()
    y = MT[index]
    y ^= y >> 11
    y ^= (y << 7) & 2636928640
    y ^= (y << 15) & 4022730752
    y ^= y >> 18

    index = (index + 1) % 624
    return y

def generate_numbers():
    "Generate an array of 624 untempered numbers"
    global MT
    for i in range(624):
        y = (MT[i] & bitmask_2) + (MT[(i + 1 ) % 624] & bitmask_3)
        MT[i] = MT[(i + 397) % 624] ^ (y >> 1)
        if y % 2 != 0:
            MT[i] ^= 2567483615

"""
Use this function!
Param:	seed (base number; should be fairly random or some source of entropy)
		num - how many numbers you want
Return: array of random numbers generated by algorithm (100 of them)
"""
def get_random_numbers(seed, num):
	initialize_generator(seed);
	a = [extract_number() for x in range(0,num)]
	return a

if __name__ == "__main__":
    import random
    seed = random.choice(range(100000))
    print get_random_numbers(seed, 10)