# Author: Ika, 2013-07-27

import numpy as np
import matplotlib.pyplot as plt
import scipy.special as sp
import random

X = np.arange(0, 50, 1)                                                                         

plt.figure()
plt.axes([0.17,0.13,0.79,0.8])
plt.hold(True)

Q = []
Y = []
# Draw the red line.
n1 = 1000
n2 = 0
for x in X:
	if x>0:
		k = 0
		t1 = t2 = 0
		while k<n1:
			k = k + 1
			if (random.random()<0.7):
				t1 = t1+1
			else:
				t2 = t2+1
		t2 = t2 + n2
		n1 = t1
		n2 = t2
	Y.append(n2)
a = plt.plot(X, Y, '*-', color='red', lw=2)
Q.append(a)

Q = []
Y = []
# Draw the black line.
n1 = 0
n2 = 1000
for x in X:
	if x>0:
		k = 0
		t1 = t2 = 0
		while k<n1:
			k = k + 1
			if (random.random()<0.7):
				t1 = t1+1
			else:
				t2 = t2+1
		k = 0
		while k<n2:
			k = k + 1
			if (random.random()<0.2):
				t1 = t1+1
			else:
				t2 = t2+1
		n1 = t1
		n2 = t2
	Y.append(n2)
a = plt.plot(X, Y, '*-', color='black', lw=2)
Q.append(a)

plt.xlim(0,50)
plt.ylim(0,1000)

plt.savefig("Markov_chain_SVG.svg")