🆕 Ising Fluctuation Model

GiulioRossetti · Mar 28, 2019 · 166d6c9 · 166d6c9
1 parent 688d4b3
commit 166d6c9
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Showing 2 changed files with 17 additions and 13 deletions.
diff --git a/ndlib/models/epidemics/IsingFluctuationModel.py b/ndlib/models/epidemics/IsingFluctuationModel.py
@@ -42,7 +42,7 @@ def __init__(self, graph):
                     "range": "[-1,1]",
                     "optional": False},
                 "T2": {
-                    "descr": "Temperature node 2",
+                    "descr": "Temperature node 2, must be grater than T1",
                     "range": "[-1,1]",
                     "optional": False}
             },
@@ -52,7 +52,7 @@ def __init__(self, graph):
 
         self.name = "IF"
 
-    def __change_status(self, u, actual_status):
+    def __change_status(self, u):
 
         neighbors = self.graph.neighbors(u)
         if isinstance(self.graph, nx.DiGraph):
@@ -61,21 +61,23 @@ def __change_status(self, u, actual_status):
         s_u = 0
         s_u_inv = 0
         for n in neighbors:
-            s_u += actual_status[u] * actual_status[n]
-            s_u_inv += (-1 * actual_status[u]) * actual_status[n]
+            s_u += self.status[u] * self.status[n]
+            s_u_inv += (-1 * self.status[u]) * self.status[n]
 
+        # regular node scenario
         if u != self.params['model']['N1'] and u != self.params['model']['N2']:
             if s_u == s_u_inv:
                 flip = random.randint(0, 1)
                 if flip == 1:
                     return True
                 return False
 
+        # Fixed temperature scenario
         dif = s_u_inv - s_u
         if u == self.params['model']['N1']:
             dif /= self.params['model']['T1']
         else:
-            dif /=  self.params['model']['T2']
+            dif /= self.params['model']['T2']
 
         if s_u_inv < s_u:
             return True
@@ -105,11 +107,13 @@ def iteration(self, node_status=True):
                 return {"iteration": 0, "status": {},
                         "node_count": node_count.copy(), "status_delta": status_delta.copy()}
 
-        for u in self.graph.nodes():
-            change = self.__change_status(u, actual_status)
-            if change:
-                actual_status[u] = -1*actual_status[u]
+        # random node selection
+        u = random.sample(list(self.graph.nodes()), 1)[0]
 
+        # spin change evaluation
+        change = self.__change_status(u)
+        if change:
+            actual_status[u] = -1*self.status[u]
 
         delta, node_count, status_delta = self.status_delta(actual_status)
         self.status = actual_status

diff --git a/ndlib/test/test_ndlib.py b/ndlib/test/test_ndlib.py
@@ -494,17 +494,17 @@ def test_ising_model(self):
         config = mc.Configuration()
         config.add_model_parameter('N1', 1)
         config.add_model_parameter('N2', 100)
-        config.add_model_parameter('T1', 1)
-        config.add_model_parameter('T2', -1)
+        config.add_model_parameter('T1', -1)
+        config.add_model_parameter('T2', 1)
 
         population = set(g.nodes()) - {n1, n2}
 
         negative_spin = random.sample(population, int(len(population)/2))
         positive_spin = list(population - set(negative_spin))
-        positive_spin.append(n1)
+        positive_spin.append(n2)
 
         negative_spin = list(negative_spin)
-        negative_spin.append(n2)
+        negative_spin.append(n1)
 
         config.add_model_initial_configuration("-1", negative_spin)
         config.add_model_initial_configuration("1", positive_spin)