target/generated-sources/template/com/flowpowered/math/GenericMath.java
public static double inverseSqrt(double a) {
        final double halfA = 0.5d * a;
        a = Double.longBitsToDouble(0x5FE6EB50C7B537AAl - (Double.doubleToRawLongBits(a) >> 1));
        return a * (1.5d - halfA * a * a);
    }
public static double inverseSqrt(double a) {
        final double halfA = 0.5d * a;
        a = Double.longBitsToDouble(0x5FE6EB50C7B537AAl - (Double.doubleToRawLongBits(a) >> 1));
        return a * (1.5d - halfA * a * a);
    }
Returns a fast estimate of the inverse square root of the value

@param a The value
@return The estimate of the inverse square root