class Archipelago

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 9
def initialize
  @populations = [] # each population is an island
  @connections = {} # an hash of array containing indexes pointing population,
                    # (sparse adjacency matrix)
  @connect_strategy = RandomConnectStrategy.new
  @migration_rate = (1.0/100.0)
  @migration_type = :random # use also :synchronized or :fixed_time
  @migration_symmetric = FALSE

  @generation_step_count = 0 #internal usage
  @populations_to_migrate_indexes = []

  reset_topological_metrics

  trigger(:on_archipelago_init)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 114
def add_edge(population_index1, population_index2)
  if population_index1 == population_index2
    return
  end
  unless @connections.has_key? population_index1
    @connections[population_index1] = []
  end
  unless @connections[population_index1].include? population_index2
    @connections[population_index1].push(population_index2)
  end
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 51
def add_population population
  @populations.push population
  reset_topological_metrics
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 104
def connect(population_index1, population_index2)
  if population_index1 == population_index2
    return
  end
  add_edge(population_index1, population_index2)
  add_edge(population_index2, population_index1)
  reset_topological_metrics
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 57
def connect_all
  @connect_strategy.connect(self)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 190
def connect_path(path, closed_path = FALSE)
  previous = nil
  previous = path[-1] if closed_path
  path.each do |current|
    connect(previous, current) unless previous.nil?
    previous = current
  end
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 34
def generation_step
  reset_populations_migration_state
  @generation_step_count += 1
  archipelago_level_migration = FALSE
  if @migration_type == :synchronized
    archipelago_level_migration = rand() < @migration_rate
  end
  if @migration_type == :fixed_time
    archipelago_level_migration = should_fixed_time_migrate
  end
  @populations.each do |population|
    population.generation_step
    migrate(population, archipelago_level_migration)
  end
  trigger(:on_archipelago_generation_step)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 162
def get_average_degree
  nodes_count = @populations.length.to_f
  edges_count = get_edges_count.to_f
  edges_count / nodes_count
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 168
def get_average_fitness
  sum = 0
  @populations.each do |population|
    sum += population.get_average_fitness
  end
  # Beware of that division by 0
  sum / @populations.length
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 177
def get_best_fitness
  best_solution = get_best_solution
  best_solution.get_fitness
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 182
def get_best_solution
  best_population = @populations.min_by do |population|
    population.get_best_fitness
  end
  best_population.get_best_solution
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 81
def get_clustering_coefficient
  unless @clustering_coefficient.nil?
    return @clustering_coefficient
  end
  @clustering_coefficient = ClusteringCoefficientMeasure.new.compute(self)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 73
def get_connected_classes_count
  ConnectedMeasure.new.compute(self)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 200
def get_degree(node)
  unless @connections.has_key?(node)
    return 0
  end
  @connections[node].length
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 77
def get_diameter
  DiameterMeasure.new.compute(self)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 143
def get_edges
  edges = []
  @connections.each do |node, facing_nodes|
    facing_nodes.each do |facing_node|
      edges.push([node, facing_node])
    end
  end
  edges
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 153
def get_edges_count
  edges_count = 0
  @connections.values.each do |target_connections|
    target_connections_length = target_connections.length
    edges_count += target_connections_length
  end
  edges_count
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 95
def get_neighbors(node)
  unless @connections.has_key?(node)
    return []
  end
  @connections[node].clone
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 89
def get_nodes
  nodes = *(0..@populations.length - 1)
  nodes
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 61
def get_population_size
  size = 0
  @populations.each do |population|
    size += population.get_population_size
  end
  size
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 69
def get_size
  @populations.size
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 136
def has_edge(population_index1, population_index2)
  unless @connections.has_key? population_index1
    return FALSE
  end
  @connections[population_index1].include? population_index2
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 127
def remove_edge(population_index1, population_index2)
  if @connections.has_key? population_index1
    @connections[population_index1].delete(population_index2)
  end
  if @connections.has_key? population_index2
    @connections[population_index2].delete(population_index1)
  end
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 302
def get_event_manager
  $dependencies.event_manager
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 290
def get_migration_period
  if @migration_rate == 0
    return FALSE
  end
  1.0 / @migration_rate
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 276
def is_population_migrated(population)
  population_index = @populations.index(population)
  # If population is migrated it's not anymore in the list
  @populations_to_migrate.index(population_index).nil?
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 270
def mark_population_as_migrated(population)
  population_index = @populations.index(population)
  @populations_to_migrate_indexes.delete(population_index)
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 209
def migrate(population, forced = FALSE)
  if (not forced) && (@migration_type != :random)
    return FALSE
  end
  unless forced
    r = rand()
    unless (r <= @migration_rate)
      return FALSE
    end
  end
  if is_population_migrated(population)
    # the population has already been migrated, we avoid to do it twice
    return FALSE
  end
  population_index = @populations.index(population)
  unless @connections.has_key?(population_index)
    return FALSE
  end
  connected_populations_indexes = @connections[population_index]
  if connected_populations_indexes.length == 0
    return FALSE
  end
  random_index = rand(connected_populations_indexes.length + 1) - 1 # +1 -1 to avoid strange suspected behavior on rand(1)
  target_population_index = connected_populations_indexes[random_index]
  if target_population_index.nil? # Why handling that case ? No idea,
                                  # a bug occurred randomly
    return FALSE
  end
  target_population = @populations[target_population_index]
  migrate_from_to(population, target_population)
  TRUE
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 242
def migrate_from_to(population, target_population)
  selected_solutions_1 = population.pick
  to_migrate_count = selected_solutions_1.length
  selected_solutions_2 = nil
  if @migration_symmetric
    selected_solutions_2 = target_population.pick
    to_migrate_count += selected_solutions_2.length
  end
  trigger(:on_archipelago_migration_begin,
          {:migrated_solutions_count => to_migrate_count})
  target_population.replace(selected_solutions_1)
  mark_population_as_migrated(population)
  unless selected_solutions_2.nil?
    population.replace(selected_solutions_2)
    mark_population_as_migrated(target_population)
  end
  trigger(:on_archipelago_migration_end,
          {:migrated_solutions_count => to_migrate_count})
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 266
def reset_populations_migration_state
  @populations_to_migrate = get_nodes
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 262
def reset_topological_metrics
  @clustering_coefficient = nil
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 282
def should_fixed_time_migrate
  migration_period = get_migration_period
  if migration_period.nil?
    return FALSE
  end
  (@generation_step_count % get_migration_period).round == 0
end

# File lib/gimuby/genetic/archipelago/archipelago.rb, line 297
def trigger(event_type, event_data = {})
  event_data[:archipelago] = self
  get_event_manager.trigger_event(event_type, event_data)
end