Ruby script to test for uniformity of random number with Chi-square algorithm.

chi_2_rndnum.py

#! /usr/local/bin/python3.6
"""
Test for uniformity of random number with Chi-square algorithm
"""
import math
import sys
import traceback


class Chi2Rndnum:
    A = 1103515245  # Multiplier
    C = 12345       # Increment
    M = 2 ** 31     # Modulus
    N = 1000        # Number to generate
    M_MAX = 10      # Range of integer random number
    F = N / M_MAX   # Expectation
    S = 40.0 / F    # Scale for histgram

    def __init__(self):
        self.r = 12345
        self.hist = [0 for _ in range(self.M_MAX + 1)]
        self.e = 0.0

    def generate_rndnum(self):
        """ Generation of random numbers """
        try:
            for _ in range(self.N):
                self.hist[self.__rnd()] += 1
        except Exception as e:
            raise

    def display(self):
        """ Calculation and display """
        try:
            for i in range(1, self.M_MAX + 1):
                print("{:>3}:{:>3} ".format(i, self.hist[i]), end="")
                for _ in range(int(self.hist[i] * self.S)):
                    print("*", end="")
                print()
                self.e = self.e \
                       + (self.hist[i] - self.F) \
                       * (self.hist[i] - self.F) / self.F
            print("Chi-square =", self.e)
        except Exception as e:
            raise

    def __rnd(self):
        """ Generation of integer between 1 and 10 """
        try:
            self.r = (self.A * self.r + self.C) % self.M
            return math.floor(self.M_MAX * (self.r / (self.M - 0.9))) + 1
        except Exception as e:
            raise


if __name__ == '__main__':
    try:
        obj = Chi2Rndnum()
        obj.generate_rndnum()
        obj.display()
    except Exception as e:
        traceback.print_exc()
        sys.exit(1)