sum_rand

import numpy as N

def genrand(num):
        return N.ones(num)/num

def combine(rand1, rand2):
        output = N.zeros(len(rand1)-1 + len(rand2))
        for i in range(len(output)):
                first = i
                second = 0
                while first >= 0:
                        if first < len(rand1) and second < len(rand2):
                                output[i] += rand1[first]*rand2[second]
                        first -= 1
                        second += 1
        return output

r1 = genrand(100)
r2 = genrand(101)
r3 = genrand(101)
randsum = combine(r1, combine(r2, r3))
final = N.zeros(100)
for i in range(len(final)):
        final[i] = randsum[3*i] + randsum[3*i + 1] + randsum[3*i + 2]