对二维矩阵中的块求和 - MATLAB [英] Sum over blocks in a 2D matrix - MATLAB

问题描述

我正在使用 Matlab，想知道如何在大型矩阵中添加项.具体来说，我有一个 4914x4914 矩阵，并想创建一个 189x189 矩阵，其中每个项等于每个 26x26 项的总和> 子集.

I'm working on Matlab and was wondering how I add terms within a large matrix. Specifically, I have a 4914x4914 matrix and would like to create a 189x189 matrix, where each term is equal to the sum of the terms in each 26x26 subset.

为了说明，假设我有一个神奇的 4x4 矩阵，如下所示:

To illustrate, say I had the magic 4x4 matrix as follows:

[16 2  3  13;

 5  11 10 8;

 9  7  6  12;

 4  14 15 1]

并且我想创建一个 2x2 矩阵，它等于原始魔术 4x4 中每个 2x2 矩阵的总和，即:

and I wanted to create a 2x2 matrix equal to the sum of each 2x2 matrix within the original magic 4x4, i.e.:

[(16+2+5+11)   (3+13+10+8);

(9+7+4+14)  (6+12+15+1)]

感谢您的任何建议！谢谢杰克

Grateful for any advice! Thanks jake

推荐答案

另一种方法是将整个矩阵重塑为 4D 矩阵，并对第一维和第三维的元素求和:

An alternative way is to reshape the whole matrix into a 4D matrix and sum the elements over first and third dimension:

result = squeeze(sum(sum(reshape(A,26,189,26,189),1),3));

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