Remove OO syntax

graph.py

@@ -3,55 +3,58 @@ from matplotlib import pyplot as plt
 
 vop_colors = ["red", "green", "blue"]
 
-class Graph(object):
-
-    def __init__(self, n):
-        self.neighbours = [set() for i in xrange(n)]
-        self.vops = [0 for i in xrange(n)]
-
-    def add_edge(self, v1, v2):
-        self.neighbours[v1].add(v2)
-        self.neighbours[v2].add(v1)
-
-    def del_edge(self, v1, v2):
-        self.neighbours[v1].remove(v2)
-        self.neighbours[v2].remove(v1)
-
-    def has_edge(self, v1, v2):
-        return v2 in self.neighbours[v1]
-
-    def toggle_edge(self, v1, v2):
-        if self.has_edge(v1, v2):
-            self.del_edge(v1, v2)
-        else:
-            self.add_edge(v1, v2)
-
-
-    def edgelist(self):
-        edges = frozenset(frozenset((i, n))
-                for i, v in enumerate(self.neighbours)
-                for n in v)
-        return [tuple(e) for e in edges]
-
-    def draw(self, filename="out.pdf", ns=500):
-        g = nx.from_edgelist(self.edgelist())
-        pos = nx.spring_layout(g)
-        colors = [vop_colors[vop] for vop in self.vops]
-        nx.draw_networkx_nodes(g, pos, node_color="white", node_size=ns)
-        nx.draw_networkx_nodes(g, pos, node_color=colors, node_size=ns, alpha=.4)
-        nx.draw_networkx_labels(g, pos)
-        nx.draw_networkx_edges(g, pos)
-
-        plt.axis('off')
-        plt.savefig(filename)
+def graph(n):
+    """ Generate a graph with Hadamards on each qubit """
+    graph = [set() for i in xrange(n)]
+    vops = [0 for i in xrange(n)]
+    return graph, vops
+
+def add_edge(graph, v1, v2):
+    """ Add an edge between two vertices in the graph """
+    graph[v1].add(v2)
+    graph[v2].add(v1)
+
+def del_edge(graph, v1, v2):
+    """ Delete an edge between two vertices in the graph """
+    graph[v1].remove(v2)
+    graph[v2].remove(v1)
+
+def has_edge(graph, v1, v2):
+    """ Test existence of an edge between two vertices in the graph """
+    return v2 in graph[v1]
+
+def toggle_edge(graph, v1, v2):
+    """ Toggle an edge between two vertices in the graph """
+    if has_edge(graph, v1, v2):
+        del_edge(graph, v1, v2)
+    else:
+        add_edge(graph, v1, v2)
+
+def edgelist(graph):
+    """ Describe a graph as an edgelist """
+    edges = frozenset(frozenset((i, n))
+            for i, v in enumerate(graph)
+            for n in v)
+    return [tuple(e) for e in edges]
+
+def draw(graph, vops, filename="out.pdf", ns=500):
+    """ Draw a graph with networkx layout """
+    g = nx.from_edgelist(edgelist(graph))
+    pos = nx.spring_layout(g)
+    colors = [vop_colors[vop] for vop in vops]
+    nx.draw_networkx_nodes(g, pos, node_color="white", node_size=ns)
+    nx.draw_networkx_nodes(g, pos, node_color=colors, node_size=ns, alpha=.4)
+    nx.draw_networkx_labels(g, pos)
+    nx.draw_networkx_edges(g, pos)
+    plt.axis('off')
+    plt.savefig(filename)
 
 if __name__ == '__main__':
-    g = Graph(10)
-    g.add_edge(0, 1)
-    g.add_edge(1, 3)
-    g.add_edge(3, 2)
-    g.add_edge(3, 0)
-    g.add_edge(2, 0)
-    print g.edgelist()
-
-    g.draw()
+    g, vops = graph(10)
+    add_edge(g, 0, 1)
+    add_edge(g, 1, 3)
+    add_edge(g, 3, 2)
+    add_edge(g, 3, 0)
+    add_edge(g, 2, 0)
+    edgelist(g)
+    draw(g, vops)