import numpy as np
import matplotlib.pyplot as plt

# **************************************************************
# lineární kongruentní generátor:

# pomocí obyčejné funkce:
def lcg1(modulus, a, b, seed):
	"""Linear congruential generator function.""" # poznámka, co funkce dělá
	return (a * seed + b) % modulus

# pomocí iterovatelné funkce (generátoru):
def lcg2(modulus, a, b, seed):
	"""Linear congruential generator."""
	while True:
		seed = (a * seed + b) % modulus
		yield seed

#****************************************************************
# prepare empty arrays:
dim = 100000
x = np.empty(dim)
y = np.empty(dim)
colors = np.empty(dim)

#****************************************************************
# použití obyčejné funkce:

a = pow(7,5)
b = 0
m = pow(2,31) - 1
N = 11

for i in range(dim):
	N = lcg1(m,a,b,N)
	x[i] = N / m
	N = lcg1(m,a,b,N)
	y[i] = N / m
	N = lcg1(m,a,b,N)
	colors[i] = N / m * 148

plt.scatter(x,y,s=0.1,c=colors)
plt.show()

#****************************************************************
# použití generátoru:

lcg_iterator = lcg2(m,a,b,11)

for i in range(dim):
	x[i] = lcg_iterator.__next__() / m
	y[i] = lcg_iterator.__next__() / m
	colors[i] = lcg_iterator.__next__() / m * 148

plt.scatter(x,y,s=0.1,c=colors)
plt.show()