I think the key point in favor of Fortran is that it is a language slightly more suited for expressing vector- and array-based math. The pointer analysis issue pointed out above is real in practice, since portable code cannot really assume that you can tell a compiler something. There is ALWAYS an advantage to expression computaitons in a manner closer to how the domain looks. C does not really have arrays at all, if you look closely, just something that kind of behaves like it. Fortran has real arrawys. Which makes it easier to compile for certain types of algorithms especially for parallel machines.

在运行时系统和调用约定等方面，C语言和现代的Fortran非常相似，很难看出有什么不同。注意，这里的C实际上是基础C: c++是一个完全不同的问题，具有非常不同的性能特征。

Fortran有更好的I/O例程，例如隐含的do工具提供了C标准库无法比拟的灵活性。

Fortran编译器直接处理更复杂的 涉及到语法，而且这样的语法不能轻易简化 参数传递形式，C不能有效地实现它。

The faster code is not really up to the language, is the compiler so you can see the ms-vb "compiler" that generates bloated, slower and redundant object code that is tied together inside an ".exe", but powerBasic generates too way better code. Object code made by a C and C++ compilers is generated in some phases (at least 2) but by design most Fortran compilers have at least 5 phases including high-level optimizations so by design Fortran will always have the capability to generate highly optimized code. So at the end is the compiler not the language you should ask for, the best compiler i know is the Intel Fortran Compiler because you can get it on LINUX and Windows and you can use VS as the IDE, if you're looking for a cheap tigh compiler you can always relay on OpenWatcom.

更多信息: http://ed-thelen.org/1401Project/1401-IBM-Systems-Journal-FORTRAN.html

我还没有听说过Fortan比C快得多，但是可以想象在某些情况下它会更快。关键不在于语言特征的存在，而在于那些(通常)不存在的特征。

一个例子是C指针。C指针几乎到处都在使用，但指针的问题是编译器通常无法判断它们是否指向同一个数组的不同部分。

例如，如果你写了一个strcpy例程，看起来像这样:

strcpy(char *d, const char* s)
{
  while(*d++ = *s++);
}

编译器必须在d和s可能是重叠数组的假设下工作。所以当数组重叠时，它不能执行会产生不同结果的优化。正如您所期望的，这在很大程度上限制了可以执行的优化类型。

[我应该注意到，C99有一个“restrict”关键字，显式地告诉编译器指针不重叠。还要注意，Fortran也有指针，语义不同于C语言，但指针不像C语言那样无处不在。

但是回到C与Fortran的问题上，可以想象，Fortran编译器能够执行一些对于(直接编写的)C程序可能无法实现的优化。所以我不会对这种说法感到太惊讶。不过，我确实希望性能差异不会太大。(~ 5 - 10%)

这两种语言具有相似的特性集。性能上的差异来自Fortran不允许混淆的事实，除非使用了EQUIVALENCE语句。任何有别名的代码都不是有效的Fortran，但是它是由程序员而不是编译器来检测这些错误的。因此，Fortran编译器忽略了可能的内存指针别名，并允许它们生成更有效的代码。看一下C语言中的这个小例子:

void transform (float *output, float const * input, float const * matrix, int *n)
{
    int i;
    for (i=0; i<*n; i++)
    {
        float x = input[i*2+0];
        float y = input[i*2+1];
        output[i*2+0] = matrix[0] * x + matrix[1] * y;
        output[i*2+1] = matrix[2] * x + matrix[3] * y;
    }
}

这个函数在优化后会比Fortran函数运行得慢。为什么如此?如果你在输出数组中写入值，你可能会改变矩阵的值。毕竟，指针可以重叠并指向相同的内存块(包括int指针!)C编译器被迫从内存中重新加载所有计算的四个矩阵值。

在Fortran中，编译器只加载一次矩阵值，并将它们存储在寄存器中。它可以这样做是因为Fortran编译器假定指针/数组在内存中不重叠。

Fortunately, the restrict keyword and strict-aliasing have been introduced to the C99 standard to address this problem. It's well supported in most C++ compilers these days as well. The keyword allows you to give the compiler a hint that the programmer promises that a pointer does not alias with any other pointer. The strict-aliasing means that the programmer promises that pointers of different type will never overlap, for example a double* will not overlap with an int* (with the specific exception that char* and void* can overlap with anything).

If you use them you will get the same speed from C and Fortran. However, the ability to use the restrict keyword only with performance critical functions means that C (and C++) programs are much safer and easier to write. For example, consider the invalid Fortran code: CALL TRANSFORM(A(1, 30), A(2, 31), A(3, 32), 30), which most Fortran compilers will happily compile without any warning but introduces a bug that only shows up on some compilers, on some hardware and with some optimization options.

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。