Class: Saulabs::TrueSkill::Factors::Prior

Inherits:
Base
  • Object
show all
Defined in:
lib/saulabs/trueskill/factors/prior.rb

Instance Method Summary collapse

Methods inherited from Base

#bind, #message_count, #reset_marginals, #send_message_at

Constructor Details

#initialize(mean, variance, variable) ⇒ Prior

Returns a new instance of Prior.



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# File 'lib/saulabs/trueskill/factors/prior.rb', line 9

def initialize(mean, variance, variable)
  super()
  @message = Gauss::Distribution.with_variance(mean, variance)
  bind(variable)
end

Instance Method Details

#log_normalization ⇒ Object 



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# File 'lib/saulabs/trueskill/factors/prior.rb', line 29

def log_normalization
  0.0
end

#update_message_at(index) ⇒ Object 



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# File 'lib/saulabs/trueskill/factors/prior.rb', line 15

def update_message_at(index)
  raise "illegal message index: #{index}" if index < 0 || index > 0
  message = @messages[index]
  variable = @variables[index]
  new_marginal = Gauss::Distribution.with_precision(
                   variable.precision_mean + @message.precision_mean - message.precision_mean,
                   variable.precision + @message.precision - message.precision
                 )
  diff = variable - new_marginal
  variable.replace(new_marginal)
  message.replace(@message)
  return diff
end