Java Math ulp() method with Examples

The java.lang.Math.ulp() is a built-in java method which returns the size of an ulp of the argument.An ulp stands for unit of least precision.It calculates the distance between the given double or float value and the
double or float value next larger in magnitude.
Arguments can be of two types :

• ulp(float f) :It takes input of float type.
• ulp(double d) :It takes input of double type.

Note :

• If the argument is NaN, Output is NaN.
• If the argument is positive or negative double or float value, Output for ulp(-arg) and ulp(arg) is same.
• If the argument is positive or negative Zero, Output will be Double.MIN_VALUE or Float.MIN_VALUE.
• If the argument is positive or negative infinity, Output is positive infinity.
• If the argument is positive or negative Double.MAX_VALUE or Float.MAX_VALUE, Output will be 2⁹⁷¹ for double type and 2¹⁰⁴ for float type.

Syntax :

public static dataType ulp(dataType g)
Parameter :
 g: argument whose ulp is to be returned.
Return :
This method returns the size of an ulp of the argument.

Example :To show working of java.lang.Math.ulp() method.

// Java program to demonstrate working
// of java.lang.Math.ulp() method
import java.lang.Math;

class Gfg {

    // driver code
    public static void main(String args[])
    {
        double a = 34.543;

        // Input positive double value
        // Output ulp(a)
        System.out.println(Math.ulp(a));

        // Input negative double value
        // Output ulp(-a)==ulp(a)
        System.out.println(Math.ulp(-a));

        double b = 0.0 / 0;

        // Input NaN, Output Nan
        System.out.println(Math.ulp(b));

        float c = -0.0f;

        // Input negative zero
        // Output  Float.MIN_VALUE.
        System.out.println(Math.ulp(c));

        float d = -1.0f / 0;

        // Input negative infinity
        // Output  positive infinity.
        System.out.println(Math.ulp(d));

        double e = Double.MAX_VALUE;

        System.out.println(Math.ulp(e));
    }
}

Output:

7.105427357601002E-15
7.105427357601002E-15
NaN
1.4E-45
Infinity
1.9958403095347198E292