Java Math.nextDown() method

The java.lang.Math.nextDown() is a built-in math method in java. It returns the floating-point value adjacent to the user specified parameter (d) in the direction of negative infinity. This method is equivalent to nextAfter(d, Double.NEGATIVE_INFINITY) method.

Implementation of nextDown may run faster than its equivalent nextAfter call.

Syntax

public static double nextDown(double a)
public static float nextDown(float a)

Parameter

Return

This method returns the adjacent floating-point value closer to negative infinity.

If the argument is a NaN, this method will return NaN.
If the argument is Zero and we are dealing with double, this method will return Double.MIN_VALUE.
If the argument is Zero and we are dealing with float, this method will return Float.MIN_VALUE.
If the argument is Negative Infinity, this method will return Negative Infinity.

Example 1

public class NextDownExample1
{
    public static void main(String[] args) 
    {
        float x = 0.0f / 0;
        // Input NaN, Output NaN
        System.out.println(Math.nextDown(x));
    }
}

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Output:

NaN

Example 2

public class NextDownExample2
{
    public static void main(String[] args) 
    {
        double x = 744.93;
        // Input double value, Output adjacent floating-point
        System.out.println(Math.nextDown(x));
    }
}

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Output:

744.9299999999998

Example 3

public class NextDownExample3 
{
    public static void main(String[] args) 
    {
        float a = 328.7f;
        // Input float value, Output adjacent floating-point
        System.out.println(Math.nextDown(a));
    }
}

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Output:

328.69998

Example 4

public class NextDownExample4 
{
    public static void main(String[] args) 
    {
        float x = 0.0f;
        // Input zero, Output Float.MIN_VALUE for float
        System.out.println(Math.nextDown(x));
    }
}

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Output:

-1.4E-45

Example 5

public class NextDownExample5
{
    public static void main(String[] args) 
    {
        double x = 0.0;
        // Input zero, Output Double.MIN_VALUE for double
        System.out.println(Math.nextDown(x));
    }
}

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Output:

-4.9E-324

Example 6

public class NextDownExample6
{
    public static void main(String[] args) 
    {
        Float x = -1.0f / 0;
        // Input negative infinity, Output negative infinity
        System.out.println(Math.nextDown(x));
    }
}

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Output: