Java Code Examples for org.apache.commons.math3.stat.StatUtils#percentile()

/**
 * Returns an estimate of the pth percentile of the values in the array along an axis.
 * @param a Input array
 * @param p The percentile value to compute
 * @param axis The axis
 * @return The pth percentile
 * @throws InvalidRangeException 
 */
public static Array percentile(Array a, double p, int axis) throws InvalidRangeException{
    int[] dataShape = a.getShape();
    int[] shape = new int[dataShape.length - 1];
    int idx;
    for (int i = 0; i < dataShape.length; i++) {
        idx = i;
        if (idx == axis) {
            continue;
        } else if (idx > axis) {
            idx -= 1;
        }
        shape[idx] = dataShape[i];
    }
    Array r = Array.factory(DataType.DOUBLE, shape);
    Index indexr = r.getIndex();
    int[] current;
    for (int i = 0; i < r.getSize(); i++) {
        current = indexr.getCurrentCounter();
        List<Range> ranges = new ArrayList<>();
        for (int j = 0; j < dataShape.length; j++) {
            if (j == axis) {
                ranges.add(new Range(0, dataShape[j] - 1, 1));
            } else {
                idx = j;
                if (idx > axis) {
                    idx -= 1;
                }
                ranges.add(new Range(current[idx], current[idx], 1));
            }
        }
        Array aa = ArrayMath.section(a, ranges);
        double[] v = (double[])aa.get1DJavaArray(Double.class);
        double q = StatUtils.percentile(v, p);
        r.setDouble(i, q);
        indexr.incr();
    }

    return r;
}
 

/**
 * Returns a double array, whose values are quantiles from the given source, based on the given
 * size. The idea is to produce size elements that represent the quantiles of source array
 *
 * @param source The array to whose quantiles are calculated
 * @param size The size of the array to return
 */
private static double[] interpolate(double[] source, int size) {
  double[] interpolatedData = new double[size];
  for (int i = 0; i < size; i++) {
    double value = ((i + .5) / (double) size) * 100;
    interpolatedData[i] = StatUtils.percentile(source, value);
  }
  return interpolatedData;
}
 

/**
 * Returns a double array, whose values are quantiles from the given source, based on the given
 * size. The idea is to produce size elements that represent the quantiles of source array
 *
 * @param source The array to whose quantiles are calculated
 * @param size The size of the array to return
 */
private static double[] interpolate(double[] source, int size) {
  double[] interpolatedData = new double[size];
  for (int i = 0; i < size; i++) {
    double value = ((i + .5) / (double) size) * 100;
    interpolatedData[i] = StatUtils.percentile(source, value);
  }
  return interpolatedData;
}
 

/**
 * Returns a double array, whose values are quantiles from the given source, based on the given
 * size. The idea is to produce size elements that represent the quantiles of source array
 *
 * @param source The array to whose quantiles are calculated
 * @param size The size of the array to return
 */
private static double[] interpolate(double[] source, int size) {
  double[] interpolatedData = new double[size];
  for (int i = 0; i < size; i++) {
    double value = ((i + .5) / (double) size) * 100;
    interpolatedData[i] = StatUtils.percentile(source, value);
  }
  return interpolatedData;
}
 

/**
 * Returns a double array, whose values are quantiles from the given source, based on the given
 * size. The idea is to produce size elements that represent the quantiles of source array
 *
 * @param source The array to whose quantiles are calculated
 * @param size The size of the array to return
 */
private static double[] interpolate(double[] source, int size) {
  double[] interpolatedData = new double[size];
  for (int i = 0; i < size; i++) {
    double value = ((i + .5) / (double) size) * 100;
    interpolatedData[i] = StatUtils.percentile(source, value);
  }
  return interpolatedData;
}
 

/**
 * Returns an estimate of the pth percentile of the values in the array.
 * @param a Input array
 * @param p The percentile value to compute
 * @return The pth percentile
 */
public static double percentile(Array a, double p){
    double[] v = (double[])a.get1DJavaArray(Double.class);
    double r = StatUtils.percentile(v, p);
    return r;
}
 

/**
 * Calculates the median of specified column
 * @param colName the column for which the median will be calculated
 * @return median
 */
public double median(String colName) {
  return StatUtils.percentile(toDoubleArray(colName), 50);
}