import random
import numpy as np
import matplotlib.pyplot as plt
import math
def randpath(tt):
y=[]
x=[]
x.append(tt)
y.append(tt)
for i in range(tt):
cc=random.random()
if cc<=0.25:
x.append(x[-1])
y.append(y[-1]+1)
elif cc<=0.5:
x.append(x[-1])
y.append(y[-1]-1)
elif cc<=0.75:
x.append(x[-1]-1)
y.append(y[-1])
else:
x.append(x[-1]+1)
y.append(y[-1])
return x,y
ss=[]
ty=640
c1=[0](2ty+1)
bn=5000
t=[]
for g in range(1,ty,5):
t.append(g)
s=0
ct=[]
for i in range(2*ty+1):
ct.append(c1[:])
for i in range(1,bn):
a,b=randpath(g)
ct[a[-1]][b[-1]]=ct[a[-1]][b[-1]]+1.0/bn
for j in range(len(ct)):
for k in range(len(ct)):
if ct[j][k]!=0:
s=s-ct[j][k]*math.log(ct[j][k])
ss.append(s)
plt.plot(t,ss)
plt.xlim(0,640)
plt.ylim(0,)
plt.xlabel('time/step number')
plt.ylabel('entropy')
plt.title('enropy versus time')
plt.show()
