strictmath

StrictMath類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給定參數的ulp的大小。 在此方法中，給定雙值參數的ulp是雙浮點值與下一個幅度較大的給定自變量double值之間的正距離。

• 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給定參數的ulp的大小。 在此方法中，給定浮點值參數的ulp是浮點浮點值與給定自變量浮點值之間的正距離，其大小隨后更大。

• These methods don't throw an exception.

  這些方法不會引發異常。

• 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.

  這些是靜態方法，可以通過類名進行訪問，如果嘗試使用類對象訪問這些方法，則不會出現任何錯誤。

Parameter(s):

參數：

• float / double – represents the value represents the double floating point value whose ulp is to be returned.

  float / double-表示該值表示要返回其ulp的double浮點值。

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.

該方法的返回類型為float / double ，它返回給定參數的ulp的大小，返回值為float / double類型。

Note:

注意：

• If we pass NaN, the method returns the same value (i.e. NaN).

  如果我們通過NaN，則該方法返回相同的值(即NaN)。

• If we pass an infinity (positive or negative), the method returns the positive infinity.

  如果我們傳遞無窮大(正數或負數)，則該方法將返回正無窮大。

• If we pass zero (positive or negative), the method returns the Float.MIN_VALUE / Double.MIN_VALUE.

  如果傳遞零(正數或負數)，則該方法返回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.

  如果傳遞Float.MAX_VALUE ，則該方法返回2的冪，以104的冪表示；如果傳遞Double.MAX_VALUE ，則該方法返回2的冪為971的冪。

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

輸出量

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

翻譯自: https://www.includehelp.com/java/strictmath-ulp-method-with-example.aspx

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