Initial similarity flooding working

[graph.njae.git] / lib / graph.njae / graph.rb

diff --git a/lib/graph.njae/graph.rb b/lib/graph.njae/graph.rb
index b1de59b324be4297ceed4ef6c1a8dd2fdfe890df..011dd8625720dd601cd4868257ae7224273fb133 100644 (file)
--- a/lib/graph.njae/graph.rb
+++ b/lib/graph.njae/graph.rb
@@ -24,18 +24,77 @@ module GraphNjae
       self
     end
     
+    # Connects two vertices, creating and storing a new edge
+    # Also adds the vertices, unless they're already in the graph
+    def connect(vertex1, vertex2)
+      self.vertices << vertex1 unless self.vertices.include? vertex1
+      self.vertices << vertex2 unless self.vertices.include? vertex2
+      edge = Edge.new
+      self.edges << edge
+      edge << vertex1 << vertex2
+    end
+    
     # Form a product graph of this graph and the other.
-    # Return the new graph.
+    # Return the product graph.
     def product(other)
       product_graph = Graph.new
       self.vertices.each do |v1|
         other.vertices.each do |v2|
-          product_vertex = Vertex.new
-          product_vertex.left_node = v1
-          product_vertex.right_node = v2
-          product_graph << product_vertex
+          product_graph << Vertex.new({:g1_vertex => v1, :g2_vertex => v2})
+        end
+      end
+      self.edges.each do |e1|
+        e1_vertices = e1.vertices
+        other.edges.each do |e2|
+          e2_vertices = e2.vertices
+          source = product_graph.vertices.find {|v| v.g1_vertex == e1_vertices[0] and v.g2_vertex == e2_vertices[0]}
+          destination = product_graph.vertices.find {|v| v.g1_vertex == e1_vertices[1] and v.g2_vertex == e2_vertices[1]}
+          product_graph.connect source, destination
+          source = product_graph.vertices.find {|v| v.g1_vertex == e1_vertices[0] and v.g2_vertex == e2_vertices[1]}
+          destination = product_graph.vertices.find {|v| v.g1_vertex == e1_vertices[1] and v.g2_vertex == e2_vertices[0]}
+          product_graph.connect source, destination
+        end
+      end
+      product_graph
+    end
+    
+    
+    def initial_similarity
+      self.vertices.each do |v|
+        if block_given?
+          v.initial_similarity = yield v
+        else
+          v.initial_similarity = 1.0
+        end
+        v.similarity = v.initial_similarity
+      end
+    end
+    
+    # Performs similarity flooding on a graph
+    # Assumes that the initial similarity has already been calculated
+    def similarity_flood(opts = {})
+      max_iterations = opts[:iterations] || 100
+      max_residual = opts[:max_residual] || 0.001
+      iteration = 1
+      residual = max_residual + 1
+      while residual > max_residual and iteration <= max_iterations
+        self.vertices.each do |v|
+          v.last_similarity = v.similarity
+        end
+        self.vertices.each do |v|
+           n = v.neighbours.length
+           v.neighbours.each do |neighbour|
+             neighbour.similarity += v.last_similarity / n
+           end
+        end
+        max_similarity = vertices.max {|v, w| v.similarity <=> w.similarity}.similarity
+        self.vertices.each do |v|
+          v.similarity = v.similarity / max_similarity
         end
+        residual = Math.sqrt(self.vertices.reduce(0) {|a, v| a += (v.similarity - v.last_similarity) ** 2})
+        iteration += 1
       end
+      
     end
     
   end # class