Module: Ms::ErrorRate::Decoy

Defined in:
lib/ms/error_rate/decoy.rb

Class Method Summary collapse

Class Method Details

.precision(num_target, num_decoy, frit = 1.0) ⇒ Object

this is the # true positives (found by estimating the number of false hits using the # decoy) frit == fraction



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# File 'lib/ms/error_rate/decoy.rb', line 8

def self.precision(num_target, num_decoy, frit=1.0)
  # will calculate as floats in case fractional amounts passed in for
  # whatever reason
  num_target_f = num_target.to_f
  num_true_pos = num_target_f - (num_decoy.to_f * frit)
  precision =
    if num_target_f == 0.0
      if num_decoy.to_f > 0.0
        0.0
      else
        1.0
      end
    else
      num_true_pos/num_target_f
    end
  precision
end