Java - Math ulp() Method

The Java Math ulp() method returns the size of the unit of least precision (ulp) of the argument. An ulp is the positive distance between the given double/float value and the double/float value next larger in magnitude. In special cases it returns the following:

• If the argument is NaN, then the result is NaN.
• If the argument is positive or negative infinity, then the result is positive infinity.
• If the argument is positive or negative zero, then the result is Double.MIN_VALUE or Float.MIN_VALUE.
• If the argument is ±Double.MAX_VALUE, then the result is equal to 2⁹⁷¹ and if the argument is ±Float.MAX_VALUE, then the result is equal to 2¹⁰⁴.

Syntax

public static double ulp(double arg)
public static float ulp(float arg)

Parameters

Return Value

Returns the size of an ulp of the argument.

Exception

NA.

Example:

In the example below, ulp() method returns the size of an ulp of the argument.

public class MyClass {
 public static void main(String[] args) {
  System.out.println(Math.ulp(25.0)); 
  System.out.println(Math.ulp(30.238)); 
  System.out.println(Math.ulp(35.5)); 
  System.out.println(Math.ulp(-25));     
 }
}

The output of the above code will be:

3.552713678800501E-15
3.552713678800501E-15
7.105427357601002E-15
1.9073486E-6