cours-m1-eea/455-Codage_Sources/algo_code/code_arithmetique.py
2019-04-30 18:28:33 +02:00

50 lines
1.5 KiB
Python
Executable file

#!/usr/bin/env python3
import numpy as np
X=[0,1,0,0,1,0,0,0,0,0]
def binary(n,m,b=2):
# Convertie un nombre décimal en sa version binaire tronqué à m bits.
binaire= np.floor(n*b**m) # on se décale dans les entiers et on floor
return binaire,np.binary_repr(int(binaire))
def arithm(X,p):
l=[0]; h= [1]
for x in X:
if x == 0:
h.append(l[-1]+p*(h[-1]-l[-1]))
l.append(l[-1])
else:
l.append(l[-1]+p*(h[-1]-l[-1]))
h.append(h[-1])
lmb = (l[-1]+h[-1])/2
mu = int(-np.log2(h[-1]-l[-1]))+1
code = binary(lmb,mu)
return code,lmb,mu
def arithm_pratique(X,p):
l = [0]; h =[1] ;f = 0;c =[] #inf, sup,follow, code
for k in range(len(X)):
print("for loop")
if X[k] == 0:
l.append(l[-1])
h.append(l[-1]+p*(h[-1]-l[-1]))
else:
l.append(l[-1]+p*(h[-1]-l[-1]))
h.append(h[-1])
while ((l[-1]>=0 and h[-1]<0.5) or (l[-1]>=0.5 and h[-1]<1) or (l[-1]>= 0.25 and h[-1]<0.75)):
if (l[-1]>=0 and h[-1]<0.5):
c += [0]+[1]*f
l[-1] *=2
h[-1] *=2
elif (l[-1]>=0.5 and h[-1]<1):
c += [1]+[0]*f
l[-1] = 2*l[-1]-1
h[-1] = 2*h[-1]-1
elif (l[-1]>= 0.25 and h[-1]<0.75):
f +=1
l[-1] = 2*l[-1]-0.5
h[-1] = 2*h[-1]-0.5
return c
print(arithm_pratique(X,p))