如何处理Java BigDecimal性能？ [英] What to do with Java BigDecimal performance?

问题描述

我为生活编写货币交易应用程序，所以我必须使用货币值（遗憾的是，Java仍然没有十进制浮动类型，并且没有任何东西可以支持任意精度的货币计算）。 使用BigDecimal！ - 你可能会说。我做。但是现在我有一些代码，其中性能 是一个问题，BigDecimal比 double 原语慢1000倍（！）。

I write currency trading applications for living, so I have to work with monetary values (it's a shame that Java still doesn't have decimal float type and has nothing to support arbitrary-precision monetary calculations). "Use BigDecimal!" — you might say. I do. But now I have some code where performance is an issue, and BigDecimal is more than 1000 times (!) slower than double primitives.

计算非常简单：系统做的是多次计算 a =（1 / b）* c （其中 a ， b 和 c 是定点值）。然而，问题在于此（1 / b）。我不能使用定点算术，因为没有固定点。并且 BigDecimal结果= a.multiply（BigDecimal.ONE.divide（b）.multiply（c）不仅难看，而且速度缓慢。

The calculations are very simple: what the system does is calculating a = (1/b) * c many many times (where a, b and c are fixed-point values). The problem, however, lies with this (1/b). I can't use fixed point arithmetic because there is no fixed point. And BigDecimal result = a.multiply(BigDecimal.ONE.divide(b).multiply(c) is not only ugly, but sluggishly slow.

我可以用什么来代替BigDecimal？我需要至少10倍的性能提升。我发现其他方面非常出色 JScience库，它具有任意精度的算术，但它甚至比BigDecimal慢。

What can I use to replace BigDecimal? I need at least 10x performance increase. I found otherwise excellent JScience library which has arbitrary-precision arithmetics, but it's even slower than BigDecimal.

有什么建议吗？

推荐答案

你应该先用a = c / b替换a =（1 / b）* c吗？它不是10x，但仍然是。

May be you should start with replacing a = (1/b) * c with a = c/b ? It's not 10x, but still something.

如果我是你，我会创建自己的类Money，这将保留很长的美元和长期美分，并在其中进行数学运算。

If I were you, I'd create my own class Money, which would keep long dollars and long cents, and do math in it.

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