code: public double falsePositiveRate(int classindex) {
      int fp = falsePositives(classindex);
      int tn = trueNegatives(classindex);
      return ((double) fp) / ((double) (fp + tn));
    }
docs: Provides the <i>false positive rate</i> for the specified class.
  
  
  @param classindex the index of the class to retrieve the false positive
  rate for
  @return the false positive rate for the specified class