strictmath_Java StrictMath ulp（）方法与示例

strictmath

StrictMath类ulp()方法 (StrictMath Class ulp() method)

Syntax:

句法：

    public static double ulp(double do);
public static float ulp(float fl);

ulp() Method is available in java.lang package.
ulp()方法在java.lang包中可用。
ulp(double do) Method is used to return the size of an ulp of the given argument in the method. In this method, an ulp of the given double value parameter is the positive distance between double floating-point value and the given argument double value next larger in magnitude.
ulp(double do)方法用于返回方法中给定参数的ulp的大小。在此方法中，给定双值参数的ulp是双浮点值与下一个幅度较大的给定自变量double值之间的正距离。
ulp(float fl) Method is used to return the size of an ulp of the given argument in the method. In this method, an ulp of the given float value parameter is the positive distance between float floating-point value and the given argument float value next larger in magnitude.
ulp(float fl)方法用于返回方法中给定参数的ulp的大小。在此方法中，给定浮点值参数的ulp是浮点浮点值与给定自变量浮点值之间的正距离，其大小随后更大。
These methods don't throw an exception.
这些方法不会引发异常。
These are static methods, it is accessible with the class name and, if we try to access these methods with the class object then we will not get any error.
这些是静态方法，可以通过类名进行访问，如果尝试使用类对象访问这些方法，则不会出现任何错误。

Parameter(s):

参数：

float / double – represents the value represents the double floating point value whose ulp is to be returned.
float / double-表示该值表示要返回其ulp的double浮点值。

Return value:

返回值：

The return type of the method is float / double, it returns the size of an ulp of the given parameter and return value is of float / double type.

该方法的返回类型为float / double ，它返回给定参数的ulp的大小，返回值为float / double类型。

Note:

注意：

If we pass NaN, the method returns the same value (i.e. NaN).
如果我们通过NaN，则该方法返回相同的值(即NaN)。
If we pass an infinity (positive or negative), the method returns the positive infinity.
如果我们传递无穷大(正数或负数)，则该方法将返回正无穷大。
If we pass zero (positive or negative), the method returns the Float.MIN_VALUE / Double.MIN_VALUE.
如果传递零(正数或负数)，则该方法返回Float.MIN_VALUE / Double.MIN_VALUE 。
If we pass Float.MAX_VALUE, the method returns the 2 raised to the power of 104 and if we pass Double.MAX_VALUE, the method returns the 2 raised to the power of 971.
如果传递Float.MAX_VALUE ，则该方法返回2的幂，以104的幂表示；如果传递Double.MAX_VALUE ，则该方法返回2的幂为971的幂。

Example:

例：

// Java program to demonstrate the example 
// of signum() method of StrictMath class
public class Ulp {
public static void main(String[] args) {
// variable declarations
double d1 = 0.0;
double d2 = -0.0;
double d3 = 7.0 / 0.0;
double d4 = -7.0 / 0.0;
double d5 = 1285.45;
float f1 = 0.0f;
float f2 = -0.0f;
float f3 = 7.0f / 0.0f;
float f4 = -7.0f / 0.0f;
float f5 = 1285.45f;
System.out.println();
System.out.println("ulp(double d:)");
// Display previous value of d1,d2,d3 ,d4and d5
System.out.println("d1:" + d1);
System.out.println("d2: " + d2);
System.out.println("d3: " + d3);
System.out.println("d4: " + d4);
System.out.println("d5: " + d5);
// Display previous value of f1,f2,f3 ,f4and d5
System.out.println("f1: " + f1);
System.out.println("f2: " + f2);
System.out.println("f3: " + f3);
System.out.println("f4: " + f4);
System.out.println("f5: " + f5);
// Here , we will get (Double.MIN_VALUE) because
// we are passing parameter (0.0)
System.out.println("StrictMath.ulp(d1): " + StrictMath.ulp(d1));
// Here , we will get (Double.MIN_VALUE) because
// we are passing parameter (-0.0) 
System.out.println("StrictMath.ulp(d2): " + StrictMath.ulp(d2));
// Here , we will get (Infinity) because
// we are passing parameter (7.0/0.0) 
System.out.println("StrictMath.ulp(d2): " + StrictMath.ulp(d3));
// Here , we will get (Infinity) because 
// we are passing parameter (-7.0/0.0)
System.out.println("StrictMath.ulp(d2): " + StrictMath.ulp(d4));
// Here , we will get (2 raised to the power of 971) because
// we are passing parameter (1285.45)
System.out.println("StrictMath.ulp(d5): " + StrictMath.ulp(d5));
System.out.println();
System.out.println("ulp(float fl:)");
// Here , we will get (Float.MIN_VALUE) because 
// we are passing parameter (0.0)
System.out.println("StrictMath.ulp(f1): " + StrictMath.ulp(f1));
// Here , we will get (Float.MIN_VALUE) because 
// we are passing parameter (-0.0) 
System.out.println("StrictMath.ulp(f2): " + StrictMath.ulp(f2));
// Here , we will get (Infinity) because 
// we are passing parameter (7.0/0.0) 
System.out.println("StrictMath.ulp(f3): " + StrictMath.ulp(f3));
// Here , we will get (Infinity) because 
// we are passing parameter (-7.0/0.0) 
System.out.println("StrictMath.ulp(f4): " + StrictMath.ulp(f4));
// Here , we will get (2 raised to the power of 971) because
// we are passing parameter (1285.45) 
System.out.println("StrictMath.ulp(f5): " + StrictMath.ulp(f5));
}
}

Output

输出量


ulp(double d:)
d1:0.0
d2: -0.0
d3: Infinity
d4: -Infinity
d5: 1285.45
f1: 0.0
f2: -0.0
f3: Infinity
f4: -Infinity
f5: 1285.45
StrictMath.ulp(d1): 4.9E-324
StrictMath.ulp(d2): 4.9E-324
StrictMath.ulp(d2): Infinity
StrictMath.ulp(d2): Infinity
StrictMath.ulp(d5): 2.2737367544323206E-13ulp(float fl:)
StrictMath.ulp(f1): 1.4E-45
StrictMath.ulp(f2): 1.4E-45
StrictMath.ulp(f3): Infinity
StrictMath.ulp(f4): Infinity
StrictMath.ulp(f5): 1.2207031E-4