rusable state graph

evrouting/gasstation/routing.py

@@ -20,10 +20,16 @@ def insert_start_node(s: Node,
                       graph_extended: nx.DiGraph,
                       capacity: SoC,
                       initial_soc: SoC,
-                      f: AccessFunctions = AccessFunctions()
+                      f: AccessFunctions = AccessFunctions(),
+                      added_nodes=None
                       ) -> nx.DiGraph:
     """Insert s into extended graph an create states and edges as necessary."""
+    if added_nodes is None:
+        added_nodes = []
+
+    added_nodes.append((s, initial_soc))
     graph_extended.add_node((s, initial_soc))
+
     v: Node
     for v in gas_stations:
         try:
@@ -38,7 +44,8 @@ def insert_start_node(s: Node,
         d = f.path_distance(graph_core, shortest_p)
         c_v = f.charging_coefficient(graph_core, v)
         g = initial_soc - w
-
+        if (v, g) not in graph_extended.nodes:
+            added_nodes.append((v, g))
         graph_extended.add_edge((s, initial_soc), (v, g), weight=d)
         for u in graph_contracted.neighbors(v):
             c_u = f.charging_coefficient(graph_contracted, u)
@@ -66,10 +73,16 @@ def insert_final_node(t: Node,
                       graph_extended: nx.DiGraph,
                       capacity: SoC,
                       final_soc: SoC,
-                      f: AccessFunctions = AccessFunctions()
+                      f: AccessFunctions = AccessFunctions(),
+                      added_nodes=None
                       ) -> nx.DiGraph:
     """Insert terminal node into extended graph an create states and edges as necessary."""
+    if added_nodes is None:
+        added_nodes = []
+
     graph_extended.add_node((t, final_soc))
+    added_nodes.append((t, final_soc))
+
     u: Node
     for u in gas_stations:
         try:
@@ -242,6 +255,8 @@ def shortest_path(G: nx.Graph,
             charge_path=[(n, 0) for n in _path]
         )
 
+    added_nodes = []
+
     contracted_graph: nx.Graph = contracted_graph or contract_graph(G, charging_stations, capacity, f)
     extended_graph = extended_graph or state_graph(contracted_graph, capacity, f)
 
@@ -253,7 +268,8 @@ def shortest_path(G: nx.Graph,
         graph_extended=extended_graph,
         capacity=capacity,
         initial_soc=initial_soc,
-        f=f
+        f=f,
+        added_nodes=added_nodes
     )
 
     extended_graph = insert_final_node(
@@ -263,17 +279,21 @@ def shortest_path(G: nx.Graph,
         graph_extended=extended_graph,
         capacity=capacity,
         final_soc=final_soc,
-        f=f
+        f=f,
+        added_nodes=added_nodes
     )
 
     try:
         path: List[State] = nx.shortest_path(extended_graph, (s, initial_soc), (t, final_soc))
     except nx.NetworkXNoPath:
-        return EmptyResult()
+        res = EmptyResult()
+    else:
+        res = compose_result(
+            graph_core=G,
+            extended_graph=extended_graph,
+            path=path,
+            f=f
+        )
 
-    return compose_result(
-        graph_core=G,
-        extended_graph=extended_graph,
-        path=path,
-        f=f
-    )
+    extended_graph.remove_nodes_from(added_nodes)
+    return res

tests/gasstation/test_transformations.py

@@ -7,7 +7,8 @@ from evrouting.gasstation.routing import (
     state_graph,
     insert_final_node,
     insert_start_node,
-    compose_result
+    compose_result,
+    shortest_path
 )
 from evrouting.graph_tools import (
     label,
@@ -325,6 +326,21 @@ class TestIntegration(Integration):
         assert len(inserted_t.edges) == 11
         assert inserted_t.edges[u, v]['weight'] == weight
 
+    def test_shortest_path_reset_state_graph(self, graph, graph_config, extended_graph, contracted_graph):
+        before = len(extended_graph.nodes)
+        shortest_path(G=graph,
+                      charging_stations=graph_config['charging_stations'],
+                      s=graph_config['s'],
+                      t=graph_config['t'],
+                      initial_soc=graph_config['initial_soc'],
+                      final_soc=graph_config['final_soc'],
+                      capacity=graph_config['capacity'],
+                      extended_graph=extended_graph,
+                      contracted_graph=contracted_graph
+                      )
+
+        assert before == len(extended_graph.nodes)
+
 
 class TestResult(Integration):
     def test_compose_result(self, graph, inserted_t):