将所有BigDecimal操作设置为一定的精度? [英] Set all BigDecimal operations to a certain precision?

问题描述

我的Java程序集中在高精度计算上，该计算必须精确到至少120个小数位.
因此，程序中所有非整数都将由BigDecimals表示.

My Java program is centered around high precision calculations, which need to be accurate to at least 120 decimal places.
Consequentially, all non-integer numbers will be represented by BigDecimals in the program.

显然，我需要为BigDecimals指定舍入的精度，以避免无限的十进制表达式等.
目前，我发现在BigDecimal的每个实例化或数学运算中都必须指定准确性非常麻烦.

Obviously I need to specify the accuracy of the rounding for the BigDecimals, to avoid infinite decimal expressions etc.
Currently, I find it a massive nuisance to have to specify the accuracy at every instantiation or mathematical operation of a BigDecimal.

是否可以为所有BigDecimal计算设置全局精度"?
(例如python中的 Decimal 模块的 Context.prec())

Is there a way to set a 'global accuracy' for all BigDecimal calculations?
(Such as the Context.prec() for the Decimal module in python)

谢谢

规格:
Java jre7 SE
Windows 7(32)

Specs:
Java jre7 SE
Windows 7 (32)

推荐答案

(几乎)原始

不是那么简单，但是您可以创建 MathContext 并将其传递给所有 BigDecimal 构造函数和执行操作的方法.

Not as simple, but you can create a MathContext and pass it to all your BigDecimal constructors and the methods performing operations.

修订版

或者，您可以扩展 BigDecimal 并通过提供正确的 MathContext 并使用 divide :

Alternatively, you can extend BigDecimal and override any operations you want to use by supplying the right MathContext, and using the rounding version of divide:

public class MyBigDecimal extends BigDecimal {

      private static MathContext context = new MathContext(120, RoundingMode.HALF_UP);

      public MyBigDecimal(String s) {
           super(s, context);
      }
      public MyBigDecimal(BigDecimal bd) {
           this(bd.toString()); // (Calls other constructor)
      }
      ...
      public MyBigDecimal divide( BigDecimal divisor ){
           return new MyBigDecimal( super.divide( divisor, context ) );
      }
      public MyBigDecimal add( BigDecimal augend ){
           return new MyBigDecimal( super.add( augend ) );
      }
      ...
}

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