为了表达平等和不平等，什么被认为是惯用的Fortran？ [英] To represent equalities and inequalities, what is considered idiomatic Fortran?

问题描述

使用通常的

  a< p> b 
x == y 
  

等等或者是

  a .lt。 b 
 x .eq。 y 
  

用得更频繁吗？

有时候我不确定什么是习惯用法，什么是使用Fortran时打卡时代的遗留问题，这可能是我没有找到答案的一种情况

解决方案

据我所知，选择只是风格，我不认为社区已经同意那个更好。 Fortran 90标准中引入了'现代'运算符（< / code>， == ...）已经出现了一段时间。

值得注意的是逻辑运算符（ .NOT。， .OR。 ...）的格式与传统关系运算符（ .NE。， .LT 。 ...）。因此，人们可以选择混搭：

 （（a <1.0）.AND。（a> 0.0 ））
  

或保持一致：

<$ p
$ （（a .LT。1.0）.AND。（a .GT。0.0））


我个人更喜欢现代形式，特别是在这些情况下，因为它有助于区分逻辑运算符和关系运算符。

在我看来，那么（dif 比（dif .LT。tol）更容易理解，特别是对于休闲或快速阅读。



我也很好奇 - 其他人会有不同的偏好吗？也许有人可以参考一个有意见的fortran风格指南。



有趣的是，对我来说一个常见的Fortran引用（ PGI Fortran ，第11页）列出了表中的所有现代操作符，使用一个单一遗留操作符的示例，并没有提及任何的其他传统运营商。


Is it more idiomatic to use the usual

a < b
x == y

and so on or is

a .lt. b
x .eq. y

used more frequently?

Sometimes I'm not sure what is idiomatic and what is just legacy from the punchcard era when using Fortran, and this is probably the one case I have not found an answer for yet.

解决方案

As far as I know, the choice is stylistic only, and I don't think the community has agreed that one is better. The 'modern' operators (<, == ...) were introduced in the fortran 90 standard so both have been around for a while.

It's worth noting that logical operators (.NOT., .OR. ...) are formatted similarly to the legacy relational operators (.NE., .LT. ...). So one can choose to mix-and-match:

 ((a < 1.0) .AND. (a > 0.0))

or be consistent:

 ((a .LT. 1.0) .AND. (a .GT. 0.0))

I personally prefer the modern form, particularly in these cases, because it helps to distinguish between logical and relational operators.

It also seems to me that (dif < tol) is easier to quickly understand than (dif .LT. tol), particularly for the casual or fast reader.

I'm curious too, though - will other people have different preferences? Perhaps somebody can reference a fortran style guide that has an opinion.

Interestingly, a common fortran reference for me (PGI Fortran, page 11) lists all the modern operators in a table, uses an example with a single legacy operator, and doesn't make mention of any of the other legacy operators.

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