Class: TruncateFactor

Inherits:
Factor
  • Object
show all
Defined in:
lib/TrueSkill/FactorGraph/TruncateFactor.rb

Instance Attribute Summary

Attributes inherited from Factor

#vars

Instance Method Summary collapse

Methods inherited from Factor

#var

Constructor Details

#initialize(var, v_func, w_func, draw_margin) ⇒ TruncateFactor

Returns a new instance of TruncateFactor.



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# File 'lib/TrueSkill/FactorGraph/TruncateFactor.rb', line 6

def initialize(var,v_func,w_func,draw_margin)
  super([var])
  @v_func=v_func
  @w_func=w_func
  @draw_margin=draw_margin
end

Instance Method Details

#up ⇒ Object 



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# File 'lib/TrueSkill/FactorGraph/TruncateFactor.rb', line 14

def up()
  val=var
  msg=var[self]
  div=val/msg
  sqrt_pi=Math.sqrt(div.pi)
  
  v=@v_func.call(div.tau/sqrt_pi,@draw_margin*sqrt_pi)
  w=@w_func.call(div.tau/sqrt_pi,@draw_margin*sqrt_pi)
  
  denom=(1.0-w)
  pi=div.pi/denom
  tau=(div.tau+sqrt_pi*v)/denom
  return var.update_value(self,pi,tau)
end