Module: GraphMatching::IntegerVertexes

Defined in:
lib/graph_matching/integer_vertexes.rb

Overview

Converts the vertices of a graph to integers. Many graph matching algorithms require integer vertexes.

Class Method Summary collapse

Class Method Details

.to_integers(graph) ⇒ Object

Converts the vertices of ‘graph` to positive nonzero integers. For example, given a graph (a=b), returns a new graph (1=2). It also returns a legend, which maps the integers to the original vertexes.

Raises:

  • (ArgumentError) 


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# File 'lib/graph_matching/integer_vertexes.rb', line 12

def self.to_integers(graph)
  raise ArgumentError unless graph.is_a?(RGL::MutableGraph)
  legend = {}
  reverse_legend = {}
  new_graph = graph.class.new
  graph.vertices.each_with_index do |vertex, ix|
    legend[ix + 1] = vertex
    reverse_legend[vertex] = ix + 1
  end
  graph.edges.each do |edge|
    source = reverse_legend[edge.source]
    target = reverse_legend[edge.target]
    new_graph.add_edge(source, target)
  end
  [new_graph, legend]
end