Merge branch 'bugfix/communty-detection-not-shared' into 'develop'

Fixes shared community detection not being shared

See merge request !11

examples/shed.py

@@ -29,6 +29,7 @@ def run_simulation(simulation):
         'tick_rate': 5 * 60,  # 5 mins
         'epoch': epoch,
         'k': 3,
+        'context': {}
     }
     nodes = {
         node_id: simulation.node_type(**node_options)

pydtn/community.py

@@ -307,6 +307,21 @@ class CommunityNode(Node):
         ]
 
 
+def shared_community(context, create):
+    """
+    Check context for shared community and return a shared community.
+
+    Use this for community detection algorithms that must have one instance
+    for a set of nodes.
+    """
+    if 'shared-community' in context:
+        return context['shared-community']
+
+    community = create()
+    context['shared-community'] = community
+    return community
+
+
 class LouvainNode(CommunityNode):
     """Wrapper to add louvain community detection automatically to a node."""
 
@@ -317,7 +332,9 @@ class LouvainNode(CommunityNode):
         Keyword Arguments:
         epoch -- how often to recalculate communities
         """
-        options['community'] = LouvainCommunity(options['epoch'])
+        def _create():
+            return LouvainCommunity(options['epoch'])
+        options['community'] = shared_community(options['context'], _create)
         super().__init__(**options)
 
 
@@ -332,7 +349,9 @@ class KCliqueNode(CommunityNode):
         epoch -- how often to recalculate communities
         k -- initial community size
         """
-        options['community'] = KCliqueCommunity(options['epoch'], options['k'])
+        def _create():
+            return KCliqueCommunity(options['epoch'], options['k'])
+        options['community'] = shared_community(options['context'], _create)
         super().__init__(**options)