diff options
Diffstat (limited to 'lib/graph.py')
| -rw-r--r-- | lib/graph.py | 48 |
1 files changed, 42 insertions, 6 deletions
diff --git a/lib/graph.py b/lib/graph.py index 58b918d..d64074a 100644 --- a/lib/graph.py +++ b/lib/graph.py @@ -156,6 +156,26 @@ class Graph: except IndexError: raise ValueError("Following from disconnected node") + def equals(self, other): + """ + Returns True if the other edge is between the same two nodes. + + Parameters + ---------- + other : `Edge` instance + + Returns + ------- + equals : bool + """ + if (self._nodes[0].equals(other._nodes[0]) and + self._nodes[1].equals(other._nodes[1])): + return True + if (self._nodes[1].equals(other._nodes[0]) and + self._nodes[0].equals(other._nodes[1])): + return True + return False + def __init__(self, polygons): """ @@ -234,9 +254,17 @@ class Graph: node : `Node` instance The new node """ - node = self.Node(point, source_polygons) - self._nodes.add(node) - return node + new_node = self.Node(point, source_polygons) + + # Don't add nodes that already exist. Update the existing + # node's source_polygons list to include the new polygon. + for node in self._nodes: + if node.equals(new_node): + node._source_polygons.update(source_polygons) + return node + + self._nodes.add(new_node) + return new_node def remove_node(self, node): """ @@ -279,9 +307,17 @@ class Graph: assert A in self._nodes assert B in self._nodes - edge = self.Edge(A, B, source_polygons) - self._edges.add(edge) - return edge + new_edge = self.Edge(A, B, source_polygons) + + # Don't add any edges that already exist. Update the edge's + # source polygons list to include the new polygon. + for edge in self._edges: + if edge.equals(new_edge): + edge._source_polygons.update(source_polygons) + return edge + + self._edges.add(new_edge) + return new_edge def remove_edge(self, edge): """ |