refactored graphs (#225)

Author: czgdp1807

pydatastructs/graphs/adjacency_list.py

@@ -19,7 +19,7 @@ def __new__(cls, *vertices):
         obj = object.__new__(cls)
         for vertex in vertices:
             obj.__setattr__(vertex.name, vertex)
-        obj.vertices = set([vertex.name for vertex in vertices])
+        obj.vertices = [vertex.name for vertex in vertices]
         obj.edge_weights = dict()
         return obj
 
@@ -32,7 +32,7 @@ def neighbors(self, node):
         return [self.__getattribute__(name) for name in node.adjacent]
 
     def add_vertex(self, node):
-        self.vertices.add(node.name)
+        self.vertices.append(node.name)
         self.__setattr__(node.name, node)
 
     def remove_vertex(self, name):
@@ -47,8 +47,7 @@ def remove_vertex(self, name):
     def add_edge(self, source, target, cost=None):
         source, target = self.__getattribute__(source), \
                          self.__getattribute__(target)
-        source.__setattr__(target.name, target)
-        source.adjacent.add(target.name)
+        source.add_adjacent_node(target.name)
         if cost is not None:
             self.edge_weights[source.name + "_" + target.name] = \
                 GraphEdge(source, target, cost)
@@ -61,7 +60,6 @@ def get_edge(self, source, target):
     def remove_edge(self, source, target):
         source, target = self.__getattribute__(source), \
                          self.__getattribute__(target)
-        source.adjacent.remove(target.name)
-        delattr(source, target.name)
+        source.remove_adjacent_node(target.name)
         self.edge_weights.pop(source.name + "_" + target.name,
                                 None)

pydatastructs/graphs/adjacency_matrix.py

@@ -17,30 +17,28 @@ class AdjacencyMatrix(Graph):
     """
     def __new__(cls, *vertices):
         obj = object.__new__(cls)
-        num_vertices = len(vertices)
         obj.vertices = [vertex.name for vertex in vertices]
         for vertex in vertices:
-            obj.__setattr__(str(vertex.name), vertex)
-        obj.matrix = OneDimensionalArray(
-                        OneDimensionalArray,
-                        num_vertices)
-        for i in range(num_vertices):
-            obj.matrix[i] = OneDimensionalArray(
-                            bool,
-                            num_vertices)
-            obj.matrix[i].fill(False)
+            obj.__setattr__(vertex.name, vertex)
+        obj.matrix = dict()
+        for vertex in vertices:
+            obj.matrix[vertex.name] = dict()
         obj.edge_weights = dict()
         return obj
 
     def is_adjacent(self, node1, node2):
-        return self.matrix[node1][node2]
+        node1, node2 = str(node1), str(node2)
+        row = self.matrix.get(node1, dict())
+        return row.get(node2, False) is not False
 
     def neighbors(self, node):
+        node = str(node)
         neighbors = []
-        for i in range(self.matrix[node]._size):
-            if self.matrix[node][i]:
+        row = self.matrix.get(node, dict())
+        for node, presence in row.items():
+            if presence:
                 neighbors.append(self.__getattribute__(
-                                 str(self.vertices[i])))
+                                 str(node)))
         return neighbors
 
     def add_vertex(self, node):
@@ -52,8 +50,9 @@ def remove_vertex(self, node):
                 "adjacency matrix for static graphs only.")
 
     def add_edge(self, source, target, cost=None):
-        self.matrix[source][target] = True
         source, target = str(source), str(target)
+        print(source, target)
+        self.matrix[source][target] = True
         if cost is not None:
             self.edge_weights[source + "_" + target] = \
                 GraphEdge(self.__getattribute__(source),
@@ -66,5 +65,6 @@ def get_edge(self, source, target):
             None)
 
     def remove_edge(self, source, target):
+        source, target = str(source), str(target)
         self.matrix[source][target] = False
         self.edge_weights.pop(str(source) + "_" + str(target), None)

pydatastructs/graphs/tests/test_adjacency_matrix.py

@@ -12,9 +12,9 @@ def test_AdjacencyMatrix():
     e1 = g.get_edge(0, 1)
     e2 = g.get_edge(1, 2)
     e3 = g.get_edge(2, 0)
-    assert (e1.source.name, e1.target.name) == (0, 1)
-    assert (e2.source.name, e2.target.name) == (1, 2)
-    assert (e3.source.name, e3.target.name) == (2, 0)
+    assert (e1.source.name, e1.target.name) == ('0', '1')
+    assert (e2.source.name, e2.target.name) == ('1', '2')
+    assert (e3.source.name, e3.target.name) == ('2', '0')
     assert g.is_adjacent(0, 1) is True
     assert g.is_adjacent(1, 2) is True
     assert g.is_adjacent(2, 0) is True

pydatastructs/utils/misc_util.py

@@ -201,7 +201,7 @@ class AdjacencyListGraphNode(GraphNode):
         in the graph. Must be unique.
     data
         The data to be stored at each graph node.
-    adjacency_list: iterator
+    adjacency_list: list
         Any valid iterator to initialize the adjacent
         nodes of the current node.
         Optional, by default, None
@@ -213,11 +213,11 @@ def __new__(cls, name, data=None, adjacency_list=None):
         if adjacency_list is not None:
             for node in adjacency_list:
                 obj.__setattr__(node.name, node)
-        obj.adjacent = set(adjacency_list) if adjacency_list is not None \
-                       else set()
+        obj.adjacent = adjacency_list if adjacency_list is not None \
+                       else []
         return obj
 
-    def add_adjacent_node(self, name, data):
+    def add_adjacent_node(self, name, data=None):
         """
         Adds adjacent node to the current node's
         adjacency list with given name and data.
@@ -227,7 +227,7 @@ def add_adjacent_node(self, name, data):
         else:
             new_node = AdjacencyListGraphNode(name, data)
             self.__setattr__(new_node.name, new_node)
-            self.adjacent.add(new_node.name)
+            self.adjacent.append(new_node.name)
 
     def remove_adjacent_node(self, name):
         """
@@ -247,7 +247,7 @@ class AdjacencyMatrixGraphNode(GraphNode):
     Parameters
     ==========
 
-    name: int
+    name: str
         The index of the node in the AdjacencyMatrix.
     data
         The data to be stored at each graph node.
@@ -257,7 +257,7 @@ class AdjacencyMatrixGraphNode(GraphNode):
     def __new__(cls, name, data=None):
         obj = GraphNode.__new__(cls)
         obj.name, obj.data, obj.is_connected = \
-            int(name), data, None
+            str(name), data, None
         obj._impl = 'adjacency_matrix'
         return obj
 

pydatastructs/utils/tests/test_misc_util.py

@@ -18,8 +18,8 @@ def test_AdjacencyListGraphNode():
     assert str(g) == "('g', 0)"
 
 def test_AdjacencyMatrixGraphNode():
-    g = AdjacencyMatrixGraphNode(1, 3)
-    assert str(g) == "(1, 3)"
+    g = AdjacencyMatrixGraphNode("1", 3)
+    assert str(g) == "('1', 3)"
 
 def test_GraphEdge():
     g_1 = AdjacencyListGraphNode('g_1', 1)