BigIntegerMath 类 |番石榴 |Java

BigIntegerMath用于对 BigInteger 值执行数学运算。基本的独立数学函数根据所涉及的主要数字类型分为IntMath、LongMath、DoubleMath 和 BigIntegerMath类。这些类具有并行结构，但每个仅支持相关的功能子集。 int 和 for long 的类似功能分别可以在 IntMath 和 LongMath 中找到。

声明： com.google.common.math.BigIntegerMath类的声明是：

@GwtCompatible(emulated = true)
public final class BigIntegerMath
   extends Object

下表显示了 BigIntegerMath 的 Guava 类提供的方法：

例外：

• log2 : IllegalArgumentException如果 x <= 0
• log10 : IllegalArgumentException如果 x <= 0
• sqrt : IllegalArgumentException如果 x < 0
• 除 : ArithmeticException如果 q == 0，或者如果 mode == UNNECESSARY 并且 a 不是 b 的整数倍
• 阶乘： IllegalArgumentException如果 n < 0
• 二项式 : IllegalArgumentException如果 n < 0, kn

示例 1：

// Java code to show implementation of
// BigIntegerMath Class of Guava
import java.math.*;
import com.google.common.math.BigIntegerMath;
  
class GFG {
  
    // Driver code
    public static void main(String args[])
    {
  
        // Creating an object of GFG class
        GFG obj = new GFG();
  
        // Function calling
        obj.examples();
    }
  
    private void examples()
    {
  
        try {
  
            // exception will be thrown as 10 is
            // not completely divisible by 3
            // thus rounding is required, and
            // RoundingMode is set as UNNESSARY
            System.out.println(BigIntegerMath.divide(BigInteger.TEN,
                                                new BigInteger("3"), 
                                           RoundingMode.UNNECESSARY));
        }
        catch (ArithmeticException ex) {
            System.out.println("Error Message is : " +
                                       ex.getMessage());
        }
    }
}

输出：

Error Message is : Rounding necessary

示例 2：

// Java code to show implementation of
// BigIntegerMath Class of Guava
import java.math.*;
import com.google.common.math.BigIntegerMath;
  
class GFG {
  
    // Driver code
    public static void main(String args[])
    {
  
        // Creating an object of GFG class
        GFG obj = new GFG();
  
        // Function calling
        obj.examples();
    }
  
    private void examples()
    {
  
        // As 10 is divisible by 5, so
        // no exception is thrown
        System.out.println(BigIntegerMath.divide(BigInteger.TEN,
                                        new BigInteger("5"),
                                    RoundingMode.UNNECESSARY));
  
        // To compute log to base 10
        System.out.println("Log10 is : " + 
             BigIntegerMath.log10(new BigInteger("1000"), 
                                 RoundingMode.HALF_EVEN));
  
        // To compute factorial
        System.out.println("factorial is : " + 
                         BigIntegerMath.factorial(7));
  
        // To compute log to base 2
        System.out.println("Log2 is : " + 
           BigIntegerMath.log2(new BigInteger("8"),
                          RoundingMode.HALF_EVEN));
  
        // To compute square root
        System.out.println("sqrt is : " +       
                    BigIntegerMath.sqrt(BigInteger.
                    TEN.multiply(BigInteger.TEN),
                        RoundingMode.HALF_EVEN));
    }
}

输出：

2
Log10 is : 3
factorial is : 5040
Log2 is : 3
sqrt is : 10

参考：谷歌番石榴