Overall node server utilisation given

Author: geraintpalmer

ciw/node.py

@@ -57,6 +57,8 @@ def __init__(self, id_, simulation):
         self.simulation.deadlock_detector.initialise_at_node(self)
         self.preempt = node.preempt
         self.interrupted_individuals = []
+        self.all_servers_total = []
+        self.all_servers_busy = []
 
     @property
     def all_individuals(self):
@@ -271,6 +273,18 @@ def find_next_individual(self):
             next_individual_index = next_individual_indices[0]
         return self.all_individuals[next_individual_index], next_individual_index
 
+    def find_server_utilisation(self):
+        """
+        Finds the overall server utilisation for the node
+        """
+        if self.c == float('Inf') or self.c == 0:
+            self.server_utilisation = None
+        else:
+            for server in self.servers:
+                self.all_servers_total.append(server.total_time)
+                self.all_servers_busy.append(server.busy_time)
+            self.server_utilisation = sum(self.all_servers_busy) / sum(self.all_servers_total)
+
     def finish_service(self):
         """
         The next individual finishes service

ciw/simulation.py

@@ -360,6 +360,7 @@ def wrap_up_servers(self, current_time):
                     srvr.total_time = current_time
                     if srvr.busy:
                         srvr.busy_time += (current_time - srvr.cust.arrival_date)
+            nd.find_server_utilisation()
 
     def source(self, c, n, kind):
         """

ciw/tests/test_node.py

@@ -579,3 +579,24 @@ def test_if_putting_individuals_in_correct_priority_queue(self):
         self.assertEqual([str(obs) for obs in N1.all_individuals], ['Individual 1', 'Individual 2'])
         self.assertEqual([[str(obs) for obs in lst] for lst in N2.individuals], [['Individual 3'], ['Individual 4']])
         self.assertEqual([str(obs) for obs in N2.all_individuals], ['Individual 3', 'Individual 4'])
+
+    def test_server_utilisation(self):
+        # Single server
+        N = ciw.create_network(
+            Arrival_distributions=[['Sequential', [2.0, 3.0, 100.0]]],
+            Service_distributions=[['Sequential', [1.0, 6.0, 100.0]]],
+            Number_of_servers=[1],
+        )
+        Q = ciw.Simulation(N)
+        Q.simulate_until_max_time(14.0)
+        self.assertEqual(Q.transitive_nodes[0].server_utilisation, 0.5)
+
+        # Multi server
+        N = ciw.create_network(
+            Arrival_distributions=[['Sequential', [2.0, 3.0, 100.0]]],
+            Service_distributions=[['Sequential', [10.0, 6.0, 100.0]]],
+            Number_of_servers=[3],
+        )
+        Q = ciw.Simulation(N)
+        Q.simulate_until_max_time(20.0)
+        self.assertEqual(Q.transitive_nodes[0].server_utilisation, 4.0/15.0)

ciw/tests/test_server.py

@@ -38,7 +38,7 @@ def test_busy_total_times(self):
         self.assertEqual(s.busy_time, 7.0)
         self.assertEqual(s.utilisation, 0.5)
 
-        # Multi serve14
+        # Multi server
         N = ciw.create_network(
             Arrival_distributions=[['Sequential', [2.0, 3.0, 100.0]]],
             Service_distributions=[['Sequential', [10.0, 6.0, 100.0]]],