Class: Evolvable::Population

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/evolvable/population.rb

Overview

Population objects are responsible for generating and evolving instances. They orchestrate all the other Evolvable objects to do so.

Populations can be initialized and re-initialized with a number of useful parameters.

Examples:

# TODO: initialize a population with all supported parameters

Constant Summary collapse

DUMP_METHODS =
%i[evolvable_type
id
name
size
evolutions_count
search_space
evolution
evaluation].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(evolvable_type: nil, evolvable_class: nil, id: nil, name: nil, size: 40, evolutions_count: 0, gene_space: nil, search_space: nil, parent_evolvables: [], evaluation: Evaluation.new, evolution: Evolution.new, selection: nil, combination: nil, mutation: nil, evolvables: []) ⇒ Population

Initializes an Evolvable::Population. Keyword arguments:

evolvable_class

Required. Implicitly specified when using EvolvableClass.new_population.

id, name

Both default to nil. Not used by Evolvable, but convenient when working with multiple populations.

size

Defaults to 40. Specifies the number of instances in the population.

evolutions_count

Defaults to 0. Useful when re-initializing a saved population with instances.

search_space

Defaults to evolvable_class.new_search_space which uses the EvolvableClass.search_space method

evolution

Defaults to Evolvable::Evolution.new. See evolution

evaluation

Defaults to Evolvable::Evaluation.new, with a goal of maximizing towards Float::INFINITY. See evaluation

instances

Defaults to initializing a size number of evolvable_class instances using the search_space object. Any given instances are assigned, but if given less than size, more will be initialized.


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# File 'lib/evolvable/population.rb', line 46

def initialize(evolvable_type: nil,
               evolvable_class: nil, # Deprecated
               id: nil,
               name: nil,
               size: 40,
               evolutions_count: 0,
               gene_space: nil, # Deprecated
               search_space: nil,
               parent_evolvables: [],
               evaluation: Evaluation.new,
               evolution: Evolution.new,
               selection: nil,
               combination: nil,
               mutation: nil,
               evolvables: [])
  @id = id
  @evolvable_type = evolvable_type || evolvable_class
  @name = name
  @size = size
  @evolutions_count = evolutions_count
  @search_space = initialize_search_space(search_space || gene_space)
  @parent_evolvables = parent_evolvables
  self.evaluation = evaluation
  @evolution = evolution
  self.selection = selection if selection
  self.combination = combination if combination
  self.mutation = mutation if mutation
  @evolvables = new_evolvables(count: @size - evolvables.count, evolvables: evolvables)
end

Instance Attribute Details

#evaluationObject

Returns the value of attribute evaluation.


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# File 'lib/evolvable/population.rb', line 107

def evaluation
  @evaluation
end

#evolutionObject

Returns the value of attribute evolution.


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# File 'lib/evolvable/population.rb', line 76

def evolution
  @evolution
end

#evolutions_countObject

Returns the value of attribute evolutions_count.


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# File 'lib/evolvable/population.rb', line 76

def evolutions_count
  @evolutions_count
end

#evolvable_typeObject

Returns the value of attribute evolvable_type.


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# File 'lib/evolvable/population.rb', line 76

def evolvable_type
  @evolvable_type
end

#evolvablesObject

Returns the value of attribute evolvables.


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# File 'lib/evolvable/population.rb', line 76

def evolvables
  @evolvables
end

#idObject

Returns the value of attribute id.


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# File 'lib/evolvable/population.rb', line 76

def id
  @id
end

#nameObject

Returns the value of attribute name.


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# File 'lib/evolvable/population.rb', line 76

def name
  @name
end

#parent_evolvablesObject

Returns the value of attribute parent_evolvables.


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# File 'lib/evolvable/population.rb', line 76

def parent_evolvables
  @parent_evolvables
end

#search_spaceObject

Returns the value of attribute search_space.


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# File 'lib/evolvable/population.rb', line 76

def search_space
  @search_space
end

#sizeObject

Returns the value of attribute size.


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# File 'lib/evolvable/population.rb', line 76

def size
  @size
end

Class Method Details

.load(data) ⇒ Object


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# File 'lib/evolvable/population.rb', line 17

def self.load(data)
  dump_attrs = Serializer.load(data)
  new(**dump_attrs)
end

Instance Method Details

#best_evolvableObject


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# File 'lib/evolvable/population.rb', line 161

def best_evolvable
  evaluation.best_evolvable(self)
end

#dump(only: nil, except: nil) ⇒ Object


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# File 'lib/evolvable/population.rb', line 203

def dump(only: nil, except: nil)
  Serializer.dump(dump_attrs(only: only, except: except))
end

#dump_attrs(only: nil, except: nil) ⇒ Object


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# File 'lib/evolvable/population.rb', line 216

def dump_attrs(only: nil, except: nil)
  attrs = {}
  dump_methods = only || DUMP_METHODS
  dump_methods -= except if except
  dump_methods.each { |m| attrs[m] = send(m) }
  attrs
end

#evolvable_classObject


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# File 'lib/evolvable/population.rb', line 199

def evolvable_class
  @evolvable_class ||= evolvable_type.is_a?(Class) ? evolvable_type : Object.const_get(evolvable_type)
end

#evolve(count: Float::INFINITY, goal_value: nil) ⇒ Object

Keyword arguments:

#### count The number of evolutions to run. Expects a positive integer and Defaults to Float::INFINITY and will therefore run indefinitely unless a goal_value is specified. #### goal_value Assigns the goal object's value. Will continue running until any instance's value reaches it. See evaluation

### Evolvable::Population#best_instance Returns an instance with the value that is nearest to the goal value.

### Evolvable::Population#met_goal? Returns true if any instance's value matches the goal value, otherwise false.

### Evolvable::Population#new_instance Initializes an instance for the population. Note that this method does not add the new instance to its array of instances.

Keyword arguments:

#### genes An array of initialized gene objects. Defaults to [] #### population_index Defaults to nil and expects an integer.

See (EvolvableClass#population_index)[#evolvableclasspopulation_index-population_index]


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# File 'lib/evolvable/population.rb', line 147

def evolve(count: Float::INFINITY, goal_value: nil)
  goal.value = goal_value if goal_value
  1.upto(count) do
    before_evaluation(self)
    evaluation.call(self)
    before_evolution(self)
    break if met_goal?

    evolution.call(self)
    self.evolutions_count += 1
    after_evolution(self)
  end
end

#met_goal?Boolean

Returns:

  • (Boolean)

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# File 'lib/evolvable/population.rb', line 165

def met_goal?
  evaluation.met_goal?(self)
end

#new_evolvable(genome: nil) ⇒ Object


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# File 'lib/evolvable/population.rb', line 169

def new_evolvable(genome: nil)
  return generate_evolvables(1).first unless genome || parent_evolvables.empty?

  evolvable = evolvable_class.new_evolvable(population: self,
                                            genome: genome || search_space.new_genome,
                                            generation_index: @evolvables.count)
  @evolvables << evolvable
  evolvable
end

#new_evolvables(count:, evolvables: nil) ⇒ Object


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# File 'lib/evolvable/population.rb', line 179

def new_evolvables(count:, evolvables: nil)
  evolvables ||= @evolvables || []
  @evolvables = evolvables

  if parent_evolvables.empty?
    Array.new(count) { new_evolvable(genome: search_space.new_genome) }
  else
    @evolvables = generate_evolvables(count)
  end
end

#new_parent_genome_cycleObject


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# File 'lib/evolvable/population.rb', line 195

def new_parent_genome_cycle
  parent_evolvables.map(&:genome).shuffle!.combination(2).cycle
end

#reset_evolvablesObject


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# File 'lib/evolvable/population.rb', line 190

def reset_evolvables
  self.evolvables = []
  new_evolvables(count: size)
end