我应该使用双精度还是浮点数? [英] Should I use double or float?

问题描述

在 C++ 中使用一种代替另一种的优点和缺点是什么?

What are the advantages and disadvantages of using one instead of the other in C++?

推荐答案

如果你想知道真正的答案，你应该阅读每个计算机科学家都应该知道的关于浮点运算的知识.

If you want to know the true answer, you should read What Every Computer Scientist Should Know About Floating-Point Arithmetic.

简而言之，虽然 double 在其表示中允许更高的精度，但对于某些计算，它会产生更大的错误.正确"的选择是:使用尽可能多的精度，但不要更多并选择正确的算法.

In short, although double allows for higher precision in its representation, for certain calculations it would produce larger errors. The "right" choice is: use as much precision as you need but not more and choose the right algorithm.

无论如何，许多编译器都在非严格"模式下进行扩展浮点数学运算(即使用硬件中可用的更广泛的浮点类型，例如 80 位和 128 位浮点)，这也应该被考虑在内.在实践中，您几乎看不出速度上的任何差异——无论如何它们都是硬件原生的.

Many compilers do extended floating point math in "non-strict" mode anyway (i.e. use a wider floating point type available in hardware, e.g. 80-bits and 128-bits floating), this should be taken into account as well. In practice, you can hardly see any difference in speed -- they are natives to hardware anyway.

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