Class: Bayesnet::Node

Inherits:
Object
  • Object
show all
Defined in:
lib/bayesnet/node.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, parent_nodes) ⇒ Node

Returns a new instance of Node.



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# File 'lib/bayesnet/node.rb', line 5

def initialize(name, parent_nodes)
  @name = name
  @parent_nodes = parent_nodes
  @values = []
  @factor = Factor.new
end

Instance Attribute Details

#factor ⇒ Object (readonly)

Returns the value of attribute factor.



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# File 'lib/bayesnet/node.rb', line 3

def factor
  @factor
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/bayesnet/node.rb', line 3

def name
  @name
end

#parent_nodes ⇒ Object (readonly)

Returns the value of attribute parent_nodes.



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# File 'lib/bayesnet/node.rb', line 3

def parent_nodes
  @parent_nodes
end

Instance Method Details

#as(distribution, given:) ⇒ Object 



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# File 'lib/bayesnet/node.rb', line 42

def as(distribution, given:)
  @values.zip(distribution).each do |value, probability|
    @factor.val [value] + given + [probability]
  end
end

#distributions(&block) ⇒ Object 



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# File 'lib/bayesnet/node.rb', line 33

def distributions(&block)
  instance_eval(&block)
end

#parameters ⇒ Object

— Node DSL —



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# File 'lib/bayesnet/node.rb', line 38

def parameters
  (values.size - 1) * parent_nodes.values.reduce(1) { |mul, n| mul * n.values.size }
end

#resolve_factor(parent_nodes) ⇒ Object 



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# File 'lib/bayesnet/node.rb', line 48

def resolve_factor(parent_nodes)
  @parent_nodes = parent_nodes
  if @factor.is_a?(Proc)
    proc = @factor
    node = self
    @factor = Factor.build do
      scope node.name => node.values
      node.parent_nodes.each do |parent_node_name, parent_node|
        scope parent_node_name => parent_node.values
      end
    end
    instance_eval(&proc)
  end
end

#values(hash_or_array = nil, &block) ⇒ Object

+++ Node DSL +++



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# File 'lib/bayesnet/node.rb', line 13

def values(hash_or_array = nil, &block)
  case hash_or_array
  when NilClass
    @values
  when Hash
    @values = hash_or_array.keys
    node = self
    @factor = Factor.build do
      scope node.name => node.values
      hash_or_array.each do |value, probability|
        val [value, probability]
      end
    end
  when Array
    raise Error, "DSL error, #values requires a &block when first argument is an Array" unless block
    @values = hash_or_array
    @factor = block
  end
end