Class: EnumMachineContrib::DecisionGraph

Inherits:
Object
  • Object
show all
Defined in:
lib/enum_machine_contrib/decision_graph.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(graph) ⇒ DecisionGraph

Returns a new instance of DecisionGraph.



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 8

def initialize(graph)
  @vertexes = Set.new
  @edges    = Set.new

  vertex_by_value = {}
  graph.each do |from_value, to_value_list|
    from_value = array_wrap(from_value)
    vertex_by_value[from_value] ||= Vertex[from_value]
    from_vertex = vertex_by_value[from_value]
    @vertexes << from_vertex

    to_value_list.sort_by(&:to_s).each do |to_value|
      to_value = array_wrap(to_value)
      vertex_by_value[to_value] ||= Vertex[to_value]
      to_vertex = vertex_by_value[to_value]
      @vertexes << to_vertex

      @edges << from_vertex.edge_to(to_vertex)
    end
  end
end

Instance Attribute Details

#edges ⇒ Object

Returns the value of attribute edges.



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 6

def edges
  @edges
end

#vertexes ⇒ Object

Returns the value of attribute vertexes.



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 6

def vertexes
  @vertexes
end

Instance Method Details

#decision_tree ⇒ Object 



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 30

def decision_tree
  drop_self_cycled_edges!
  combine_equal_vertexes!

  loop do
    complexity_was = complexity

    decision_tree = DecisionTree.wrap(to_h)
    decision_tree.resolve!
    resolved_decision_tree = decision_tree.resolved

    edges.each do |edge|
      next unless resolved_decision_tree.key?(edge.from.value)

      if resolved_decision_tree[edge.from.value].any? { |to_value_list| to_value_list.include?(edge.to.value) }
        edge.resolved!
      end
    end

    strongly_connected_components = decision_tree.values.filter(&:cycled?)
    strongly_connected_components.each do |strongly_connected_component|
      resolve_strong_component!(strongly_connected_component)
    end

    break if complexity == complexity_was
  end

  decision_tree = DecisionTree[vertexes.index_by(&:value)]
  decision_tree.resolve!
  decision_tree
end

#next_achievable_vertexes(vertex, all, visited: Set.new) ⇒ Object 



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 183

def next_achievable_vertexes(vertex, all, visited: Set.new)
  return [] if visited.include?(vertex)

  achievable_vertexes = [vertex]
  visited << vertex

  vertex.outcoming_edges.each do |edge|
    if all.include?(edge.to)
      achievable_vertexes += next_achievable_vertexes(edge.to, all, visited: visited)
    end
  end

  achievable_vertexes
end

#resolve_strong_component!(component_cycled_vertex) ⇒ Object

rubocop:disable Metrics/CyclomaticComplexity,Metrics/PerceivedComplexity



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 95

def resolve_strong_component!(component_cycled_vertex) # rubocop:disable Metrics/CyclomaticComplexity,Metrics/PerceivedComplexity
  input_values  = component_cycled_vertex.incoming_edges.flat_map { |edge| edge.from.value }
  output_values = component_cycled_vertex.outcoming_edges.flat_map { |vertex| vertex.to.value }

  active_vertexes = vertexes.filter(&:active?)
  input_vertexes  = active_vertexes.reject { |vertex| (input_values & vertex.value).empty? }
  output_vertexes = active_vertexes.reject { |vertex| (output_values & vertex.value).empty? }

  component_vertexes = active_vertexes.reject { |vertex| (component_cycled_vertex.value & vertex.value).empty? }

  component_vertexes.each do |vertex|
    vertex.incoming_edges.each do |edge|
      if (input_vertexes + component_vertexes).exclude?(edge.from)
        # drop insignificant incoming edges
        edge.dropped!
      end
    end
  end

  single_incoming_vertexes = (component_vertexes + output_vertexes).filter { |vertex| vertex.incoming_edges.size == 1 }

  single_incoming_chains = []
  single_incoming_vertexes.each do |vertex|
    single_incoming_edge = vertex.incoming_edges.first
    single_incoming_edge.resolved!

    current_chain = single_incoming_chains.detect { |chain| chain.first == single_incoming_edge.to || chain.last == single_incoming_edge.from }
    if current_chain
      current_chain.replace(
        if current_chain.first == single_incoming_edge.to
          current_chain.unshift(single_incoming_edge.from)
        else
          current_chain.push(single_incoming_edge.to)
        end,
      )
    else
      single_incoming_chains << [single_incoming_edge.from, single_incoming_edge.to]
    end
  end

  single_incoming_chains.each do |chain|
    chain_preceding_vertexes  = chain[0].incoming_edges.map(&:from) & (input_vertexes + component_vertexes)
    chain_achievable_vertexes = chain[1..].flat_map { |vertex| vertex.outcoming_edges.map(&:to) }

    pre_chain_vertexes = chain_preceding_vertexes - chain_achievable_vertexes

    if pre_chain_vertexes.size == 1
      single_incoming_edge = chain[0].incoming_edges.detect { |edge| edge.from == pre_chain_vertexes[0] }
      single_incoming_edge.resolved!

      chain.unshift(single_incoming_edge.from)
    end

    chain.flat_map { |vertex| vertex.outcoming_edges.to_a }.group_by(&:to).each_value do |outcoming_edges|
      next if outcoming_edges.size < 2

      outcoming_edges[0..outcoming_edges.size - 2].each(&:dropped!)
    end
  end

  around_vertexes = input_vertexes + component_vertexes + output_vertexes

  component_vertexes.each do |maybe_bottlneck_vertex|
    rest_vertexes = around_vertexes.excluding(maybe_bottlneck_vertex)

    input_achievable_vertexes = next_achievable_vertexes(input_vertexes[0], rest_vertexes, visited: Set.new([maybe_bottlneck_vertex]))
    next if input_achievable_vertexes.size == rest_vertexes.size

    maybe_bottlneck_vertex.outcoming_edges.each do |current_edge|
      if input_achievable_vertexes.include?(current_edge.to) && maybe_bottlneck_vertex.incoming_edges.map(&:from).exclude?((current_edge.to))
        current_edge.to.incoming_edges.each do |edge|
          unless edge.from == maybe_bottlneck_vertex
            edge.dropped!
          end
        end
      end
    end

    rest_vertexes -= input_achievable_vertexes

    maybe_bottlneck_vertex.incoming_edges.each do |edge|
      if rest_vertexes.include?(edge.from)
        edge.dropped!
      end
    end
  end
end

#to_h ⇒ Object 



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# File 'lib/enum_machine_contrib/decision_graph.rb', line 62

def to_h
  vertexes.filter(&:active?).to_h do |vertex|
    [
      vertex.value,
      vertex.outcoming_edges.map { |edge| edge.to.value },
    ]
  end
end