code: public double[] interpolated11PointPrecision()
      {
          double[] interpolatedPrecision = new double[11];
          int numCorrectAtRankI = 0;
          for (int i=0; i<pairs.length; i++) {
              if (correctPair(i)) ++numCorrectAtRankI;
              double recall = numCorrectAtRankI/((double)numCorrectPairs);
              double precision = numCorrectAtRankI/(i+1.0);
              for (int j=0; j<elevenPoints.length; j++) {
                  if (recall>=elevenPoints[j]) {
                      interpolatedPrecision[j] = Math.max(interpolatedPrecision[j], precision);
                  }
              }
          }
          return interpolatedPrecision;
      }
docs: Return an array of interpolated precision at various different recall levels.