我不时地读到Fortran在繁重的计算中比C更快。这是真的吗?我必须承认我几乎不懂Fortran,但是到目前为止我看到的Fortran代码并没有显示出该语言具有C语言所不具备的特性。

如果是真的,请告诉我原因。请不要告诉我什么语言或库适合处理数字,我不打算写一个应用程序或库来做这个,我只是好奇。


当前回答

Fortran可以非常方便地处理数组,特别是多维数组。在Fortran中对多维数组元素进行切片比在C/ c++中容易得多。c++现在有库可以做这项工作,比如Boost或Eigen,但它们毕竟是外部库。在Fortran中,这些函数是固有的。

对于开发来说,Fortran是更快还是更方便主要取决于您需要完成的工作。作为地球物理的科学计算人员,我用Fortran(我指的是现代Fortran, >=F90)进行了大部分计算。

其他回答

I was doing some extensive mathematics with FORTRAN and C for a couple of years. From my own experience I can tell that FORTRAN is sometimes really better than C but not for its speed (one can make C perform as fast as FORTRAN by using appropriate coding style) but rather because of very well optimized libraries like LAPACK (which can, however, be called from C code as well, either linking against LAPACK directly or using the LAPACKE interface for C), and because of great parallelization. On my opinion, FORTRAN is really awkward to work with, and its advantages are not good enough to cancel that drawback, so now I am using C+GSL to do calculations.

Fortran和C之间的速度差异更多的是编译器优化和特定编译器使用的底层数学库的函数。Fortran没有什么固有的特性可以使它比C更快。

不管怎样,一个优秀的程序员可以用任何语言编写Fortran。

大多数帖子已经提出了令人信服的论点,所以我只是在另一个方面加上众所周知的2美分。

在处理能力方面,fortran更快或更慢是有其重要性的,但如果用fortran开发一些东西需要5倍多的时间,因为:

it lacks any good library for tasks different from pure number crunching it lack any decent tool for documentation and unit testing it's a language with very low expressivity, skyrocketing the number of lines of code. it has a very poor handling of strings it has an inane amount of issues among different compilers and architectures driving you crazy. it has a very poor IO strategy (READ/WRITE of sequential files. Yes, random access files exist but did you ever see them used?) it does not encourage good development practices, modularization. effective lack of a fully standard, fully compliant opensource compiler (both gfortran and g95 do not support everything) very poor interoperability with C (mangling: one underscore, two underscores, no underscore, in general one underscore but two if there's another underscore. and just let not delve into COMMON blocks...)

那么这个问题就无关紧要了。如果某样东西很慢,大多数时候你无法在给定的限制范围内改进它。如果你想要更快,改变算法。最后,使用电脑的时间很便宜。人类的时间不是。珍惜减少人类时间的选择。如果它增加了使用电脑的时间,无论如何它都是有成本效益的。

没有一种语言比另一种语言更快,所以正确的答案是否定的。

你真正要问的是“用Fortran编译器X编译的代码是否比用C编译器Y编译的等效代码更快?”这个问题的答案当然取决于您选择哪两个编译器。

人们可能会问的另一个问题是“考虑到在他们的编译器中优化投入了相同的精力,哪个编译器会生成更快的代码?” 这个问题的答案实际上是Fortran。Fortran编译器有一些优势:

Fortran had to compete with Assembly back in the day when some vowed never to use compilers, so it was designed for speed. C was designed to be flexible. Fortran's niche has been number crunching. In this domain code is never fast enough. So there's always been a lot of pressure to keep the language efficient. Most of the research in compiler optimizations is done by people interested in speeding up Fortran number crunching code, so optimizing Fortran code is a much better known problem than optimizing any other compiled language, and new innovations show up in Fortran compilers first. Biggie: C encourages much more pointer use than Fortran. This drasticly increases the potential scope of any data item in a C program, which makes them far harder to optimize. Note that Ada is also way better than C in this realm, and is a much more modern OO Language than the commonly found Fortran77. If you want an OO langauge that can generate faster code than C, this is an option for you. Due again to its number-crunching niche, the customers of Fortran compilers tend to care more about optimization than the customers of C compilers.

然而,没有什么能阻止人们在C编译器的优化上投入大量精力,并使其生成比他们平台的Fortran编译器更好的代码。事实上,C编译器产生的较大销售额使得这种情况非常可行

我是一个业余程序员,在这两种语言上我都是“平均”。 我发现编写快速Fortran代码比编写C(或c++)代码更容易。Fortran和C都是“历史悠久”的语言(按照今天的标准),被大量使用,并且很好地支持免费和商业编译器。

我不知道这是否是一个历史事实,但Fortran感觉它是为并行/分布式/向量化/多核化而构建的。今天,当我们谈论速度时,它几乎是“标准度量”:“它能缩放吗?”

对于纯粹的cpu计算,我喜欢Fortran。对于任何与IO相关的东西,我发现使用c更容易(无论如何这两种情况都很困难)。

当然,对于并行计算密集型代码,你可能需要使用GPU。C和Fortran都有很多或多或少很好地集成了CUDA/OpenCL接口(现在还有OpenACC)。

我比较客观的回答是:如果你对这两种语言都同样了解或不了解,那么我认为Fortran更快,因为我发现用Fortran写并行/分布式代码比用c更容易(一旦你明白你可以写“自由形式”Fortran,而不仅仅是严格的F77代码)

Here is a 2nd answer for those willing to downvote me because they don't like the 1st answer : Both language have the features required to write high-performance code. So it's dependent of the algorithm you're implementing (cpu intensive ? io intensive ? memory intensive?), the hardware (single cpu ? multi-core ? distribute supercomputer ? GPGPU ? FPGA ?), your skill and ultimately the compiler itself. Both C and Fortran have awesome compiler. (i'm seriously amazed by how advanced Fortran compilers are but so are C compilers).

PS:我很高兴你特别排除了库,因为我有很多关于Fortran GUI库的不好的东西要说。:)