ajout code huffman et arithmétique

455-Codage_Sources/algo_code/code_arithmetique.py

+#!/usr/bin/env python3
+
+import numpy as np
+
+
+p_s = [0.1,0.9]
+P = np.random.rand(N)
+X =  [0 for p in P if p > p_s[0] else 1]
+
+
+def binary(n,b=2,m):
+    """
+    Convertie un nombre décimal en sa version binaire tronqué à m bits.
+    """
+    return np.ceil(n*b**m)
+
+def arithm(X):
+    l=[0]
+    h= [1]
+    for x in X:
+        if x == 0:
+            h.append(l[-1]+p_s[0]*(h[-1]-l[-1]))
+            l.append(l[-1])
+        else:
+            l.append(l[-1]+p_s[0]*(h[-1]-l[-1]))
+            h.append(h[-1])
+
+            lmb = (l[-1]+h[-1])/2
+            mu = int(-np.log2(h[-1]-l[-1]))+1

455-Codage_Sources/algo_code/gen_markov1.py

+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+Created on Mon Jan 28 12:31:21 2019
+
+@author: pac
+"""
+
+import numpy as np
+P = [[0.8,0.1,0.1],[0.1,0.7,0.2],[0.1,0.2,0.7]]
+def get_state(p,cump):
+    print(p, cump)
+    for i in range(len(cump)):
+        if p < cump[i]:
+            return i
+
+def gen_markov1(N,P,init_state=0):
+    cumP = np.cumsum(P,1)
+    states = [init_state]
+    p = np.random.rand(N)
+    for k in range(N):
+         states.append(get_state(p[k],cumP[states[-1]]))
+    return states
+print(gen_markov1(100,P,init_state=1))

455-Codage_Sources/algo_code/huffman.py

+#!/usr/bin/python3
+
+import numpy as np
+
+def get_2min(l):
+    min1 = 0
+    min2 = 1
+    for k in range(1,len(l)):
+        if l[k]<=l[min1]:
+            min2 = min1
+            min1 = k
+        elif l[k]<=l[min2]:
+            min2 = k
+    return min1,min2
+
+def huffman_rec(p):
+    if len(p) == 2:
+        C = ['1','0']
+        print(p,C)
+        return C
+    else:
+       min1,min2 = get_2min(p)
+       min1,min2 = min(min1,min2),max(min1,min2)
+       print(p,min1,min2)
+       p_save=p.pop(min2)
+       p[min1] = p[min1]+p_save
+       C = huffman_rec(p)
+       C.insert(min2,C[min1]+'1')
+       C[min1] +='0'
+       p.insert(min2,p_save)
+       p[min1] -= p_save
+       print(p,C)
+       return C
+
+p = [25,20,15,12,10,8,5,5]
+
+print(huffman_rec(p))

455-Codage_Sources/algo_code/huffman2.py

+#!/usr/bin/env python3
+
+import subprocess
+
+class Noeud(object):
+    def __init__(self,p=0,left=None,right=None,code='',name=''):
+        self.left = left
+        self.right= right
+        if left != None and right != None :
+            self.p = left.p + right.p
+            self.name =left.name+right.name
+        else:
+            self.p = p
+            self.name = name
+        self.code = code
+    def __lt__(self,other):
+        return self.p<other.p
+    def __repr__(self):
+        return self.name
+
+table = [
+    ('A', 25),
+    ('B', 20),
+    ('C', 15),
+    ('D', 12),
+    ('E', 10),
+    ('F', 8),
+    ('G', 5),
+    ('H', 5)]
+
+table_noeud = [Noeud(name=x[0],p=x[1]) for x in table]
+#print(table_noeud)
+def create_tree(table_noeud):
+    queue = table_noeud.copy()
+    while len(queue) > 2:
+        queue.sort()
+        print(queue)
+        l=queue.pop(0)
+        r=queue.pop(0)
+        queue.append(Noeud(left=l,right=r))
+    root= Noeud(left=queue[0],right=queue[1])
+    return root
+root_node= create_tree(table_noeud)
+print(root_node)
+
+def gen_code(node,prefix=''):
+    if node.left != None:
+        node.code = prefix
+        gen_code(node.left,prefix+'0')
+        gen_code(node.right,prefix+'1')
+    else:
+        node.code = prefix
+        print(node.name,node.code)
+
+gen_code(root_node)
+
+def draw_tree(node):
+    if len(node.name) == 1: # feuille
+        desc ='N{} [label="{}:{}", fontcolor=blue, fontsize=16, width=2, shape=box];\n'.format(node.code, node.name, node.code)
+    else:
+        desc = 'N{} [label="{}"];\n'.format(node.code,node.code)
+        desc += draw_tree(node.left)
+        desc += draw_tree(node.right)
+        desc += 'N{}:n -> N{}:e;\n'.format(node.code,node.left.code)
+        desc += 'N{}:s -> N{}:e;\n'.format(node.code,node.right.code)
+    return desc
+
+with open('graph.dot','w') as f:
+    f.write('digraph G {\n ')
+    f.write(' splines=ortho \n')
+    f.write('rankdir=RL;\n')
+    f.write(draw_tree(root_node))
+    f.write('{rank =same; N' + '; N'.join([n.code for n in table_noeud]) +';}\n')
+    f.write('}')
+subprocess.call('dot -Tpng graph.dot -o graph.png', shell=True)
+print('done')