Fortran中多维数组的索引线性 [英] Linear Indexing of Multi-Dimension Arrays in Fortran

问题描述

设A是DIMENSION（M，N，P）的多维数组。是一个线性索引（使用一个索引）允许用Fortran？如果是这样，什么是线性指标和多维指数之间的对应关系？

Let A be a multi-dimensional array of DIMENSION(m,n,p). Is linear indexing of A (using a single index) allowed in Fortran? If so, what is correspondence between the linear index and the multi-dimensional index?

在换句话说，就是A（一）允许的，哪些元素做了（我）对应于（其中依次是尺寸遍历）？

In other words, is A(i) allowed, and which element does A(i) correspond to (in which order are the dimensions traversed)?

推荐答案

的http：// www.obliquity.com/computer/fortran/array.html 的解释数组存储在列为主的形式，从而使最左边的索引的最迅速的变化，其次是第二到最左边的等（这是C的对面，我相信）。它似乎很不明智的索引多维数组，就好像是一维的，但上面的链接页面说明，你的编译器将产生code，它就是这样做的（因此是非常快）的只要你嵌套你的循环以正确的顺序的

http://www.obliquity.com/computer/fortran/array.html explains that arrays are stored in "column-major" form, so that the left most index changes the most quickly, followed by the second to leftmost, etc. (this is the opposite of C, I believe). It seems quite unwise to try to index a multidimensional array as though it were one-dimensional, but as the above-linked page explains, your compiler will produce code that does just that (and is therefore very fast) as long as you nest your loops in the right order.

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