def gap_validation(prediction_raw, sm)
      return 1 if prediction_raw.length != sm.length
      # find gaps in the prediction and
      # not in the statistical model
      no_gaps = 0
      (0..sm.length - 1).each do |i|
        no_gaps += 1 if prediction_raw[i] == '-' && sm[i] != '-'
      end
      no_gaps / (sm.length + 0.0)
    end
def gap_validation(prediction_raw, sm)
      return 1 if prediction_raw.length != sm.length
      # find gaps in the prediction and
      # not in the statistical model
      no_gaps = 0
      (0..sm.length - 1).each do |i|
        no_gaps += 1 if prediction_raw[i] == '-' && sm[i] != '-'
      end
      no_gaps / (sm.length + 0.0)
    end
Returns the percentage of gaps in the prediction
 with respect to the statistical model
 Params:
 +prediction+: +String+ corresponding to the prediction sequence
 +sm+: +String+ corresponding to the statistical model
 Output:
 +Fixnum+ with the score