From 06b30a66c029b9f923c5720f3f22564ff8f3bc20 Mon Sep 17 00:00:00 2001
From: Ikenna Oluigbo <ikenna-victor.oluigbo@etu.univ-lyon1.fr>
Date: Fri, 17 Jun 2022 08:56:42 +0000
Subject: [PATCH] Upload identitywalker file

---
 identity2vec.py | 148 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 identity2vec.py

diff --git a/identity2vec.py b/identity2vec.py
new file mode 100644
index 0000000..0eac056
--- /dev/null
+++ b/identity2vec.py
@@ -0,0 +1,148 @@
+import numpy as np 
+import networkx as nx
+from tqdm import tqdm
+import time
+from decimal import Decimal
+
+
+class Graph():
+    def __init__(self, nx_Graph, e):
+        self.G = nx_Graph
+        self.e = e
+   
+    
+    def degree_node(self):
+        G = self.G
+        deg_dict = {}
+        for node, deg in G.degree:
+            deg_dict[node] = deg
+        return deg_dict 
+    
+    
+    def eigenvector_centrality(self):
+        G = self.G
+        ev = nx.eigenvector_centrality(G, max_iter=1000)
+        return ev
+    
+        
+    def node_neighbors(self):
+        G = self.G
+        node_neigh = {}
+        for node in G.nodes:
+            node_neigh[node] = list(G.neighbors(node))
+        return node_neigh
+
+
+    def test_source(self, s):
+        mnn = self.node_neighbors()[s] 
+        arr_new_nn = np.array(mnn)
+        np.random.shuffle(arr_new_nn)
+        next_node = np.random.choice(arr_new_nn)
+        return next_node
+    
+    
+    def skip_visited(self, snn, visited):
+        if len(snn) != 1:
+            if len(visited) > 1:
+                last_visit = visited[-2]
+                if last_visit in snn:
+                    snn.remove(last_visit)
+                    self.skip_visited(snn, visited)
+        return snn
+    
+    
+    def identity_walker(self, node, walk_length):
+        walk = [node]
+        visited = [node]
+        while len(walk) < walk_length:
+            current_node = walk[-1]
+            nn = self.node_neighbors()[current_node] 
+            if len(nn) == 0:
+                break 
+            if visited[-1] == node:
+                next_node = self.test_source(visited[-1])
+                walk.append(next_node)
+                visited.append(next_node)
+            else:
+                nn = self.skip_visited(nn, visited)
+                bounded_curr = walk[-2]
+                pdn = self.poisson_dist(nn, bounded_curr)
+                next_node = min(pdn, key=pdn.get) 
+                walk.append(next_node)
+                visited.append(next_node) 
+                
+        return walk
+    
+    
+    def s_path(self, source, destination): 
+        G = self.G
+        if nx.has_path(G, source, destination):
+            path = nx.shortest_path(G, source, destination)
+            path_length = nx.shortest_path_length(G, source, destination) 
+        else:
+            path = []
+            path_length = len(path)
+        return path, path_length
+    
+       
+    def get_prob(self, n, curr):
+        G = self.G
+        neigh = list(G.neighbors(n))
+        p_val = self.degree_node()
+        ev = self.eigenvector_centrality()
+        p = []
+        q = []
+        for node in neigh:
+            _, path_length = self.s_path(curr, node)
+            path_length += 0.01     #Prevent PathLength 0
+            p.append(p_val[node] * ev[node])
+            q.append(path_length)
+        return p, q
+        
+    
+    def poisson_dist(self, mnn, bounded_curr):
+        #k = Number of adjacent neighbors
+        #λ = Divergence rate
+        #pdn = (λ**k * e**-λ) / k! 
+        #KLDivergence = #sum(p(x) * log(p(x)/q(x)))
+        e = self.e
+        pdn = {}
+        k = len(mnn)       
+        for node in mnn:
+            rt = 0
+            p, q = self.get_prob(node, bounded_curr)
+            for i in range(len(p)):
+                t = p[i] * np.log(p[i] / q[i])
+                rt += t 
+            drt = (1 / (self.degree_node()[bounded_curr]+self.eigenvector_centrality()[bounded_curr])) * rt
+            #poiss = Decimal((np.power(drt, k) * np.power(e, -drt))) / Decimal(np.math.factorial(k))
+            poiss = (np.power(drt, k) * np.power(e, -drt)) / (np.math.factorial(k))
+            pdn[node] = poiss
+        return pdn
+    
+    
+    def identity2vec_walk(self, num_walk, walk_length):
+        
+        G = self.G
+        print("STARTING RANDOM WALK... ")
+        print("Number of Nodes:", len(G.nodes))
+        time.sleep(3)
+        
+        nodes = list(G.nodes)
+        walk_corpus = []
+        
+        for cw in range(1, num_walk+1):
+            print("\n")
+            print("Current Walk: " + str(cw) + " of " + str(num_walk))
+            for node in tqdm(nodes):
+                node_walk = self.identity_walker(node, walk_length)
+                walk_corpus.append(node_walk)            
+               
+        return walk_corpus
+    
+
+
+
+
+    
+    
\ No newline at end of file
-- 
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