private static double qMinus(
		final double mm,
		final double m0,
		final double m1,
		final double m2,
		final double q0,
		final double q1,
		final double q2
	) {
		double result =
			q1 -
			((mm - m0)*(q2 - q1)/(m2 - m1) +
			(m2 - mm)*(q1 - q0)/(m1 - m0))/(m2 - m0);

		if (q0 > result) {
			result = q1 + (q0 - q1)/(m0 - m1);
		}

		return result;
	}
Combine two {@code Quantile} objects.

@since 3.1

@param other the other {@code Quantile} object to combine
@return {@code this}
@throws java.lang.NullPointerException if the {@code other} object is
        {@code null}.
@throws java.lang.IllegalArgumentException if the {@link #quantile}
        of the {@code other} object differs from {@code this} one.
jenetics/src/main/java/io/jenetics/stat/Quantile.java