找到一个非常大的矩阵的转置 [英] Finding the transpose of a very, very large matrix

问题描述

我有这个巨大的二维数据数组.它以行顺序存储:

A(1,1)A(1,2)A(1,3)..... A(n-2，n)A(n-1，n)A(n，n)

我想将其重新排列为列顺序

A(1,1)A(2,1)A(3,1)..... A(n，n-2)A(n，n-1)A(n，n)

数据集非常大-超出了计算机RAM上的容量. (n约为10,000，但每个数据项占用约1K的空间.)

有人知道精巧或有效的算法吗?

解决方案

创建n空文件(如果可以的话，为n元素保留足够的空间).遍历原始矩阵.将元素(i,j)追加到文件j.完成此操作后，请附加刚刚编写的文件.

I have this huge 2 dimensional array of data. It is stored in row order:

A(1,1) A(1,2) A(1,3) ..... A(n-2,n) A(n-1,n) A(n,n)

I want to rearrange it into column order

A(1,1) A(2,1) A(3,1) ..... A(n,n-2) A(n,n-1) A(n,n)

The data set is rather large - more than will fit on the RAM on a computer. (n is about 10,000, but each data item takes about 1K of space.)

Does anyone know slick or efficient algorithms to do this?

解决方案

Create n empty files (reserve enough space for n elements, if you can). Iterate through your original matrix. Append element (i,j) to file j. Once you are done with that, append the files you just wrote.

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