Matlab:矩阵的最小值 [英] Matlab : Minimum of matrix

问题描述

我需要找到整个矩阵的最小值，它是坐标". 在类似

I need to find the minimum of an entire matrix and it's 'coordinates'. In a matrix like

matrix = 8 7 6 5  
         4 3 2 1

在(2，4)处最小值为1.

The minimum would be 1 at (2, 4).

推荐答案

这可以非常简单地通过使用 find ，您将在其中使用它的两个输出版本.因此，您要做的就是搜索矩阵中与矩阵最小值匹配的行和列位置.

This can very simply be done by using find, where you would use the two output version of it. So what you want to do is search for those row and column locations in your matrix that match the minimum value in your matrix.

因此:

[row, col] = find(matrix == min(matrix(:)));

row和col将包含等于此最小值的matrix的行和列位置.请注意，我必须通过执行matrix(:)将矩阵展开为向量.之所以这样，是因为如果您要在矩阵上使用min，则默认情况下它将为您提供沿每一列的最小值.因为要查找整个矩阵的最小值，所以可以将其转换为单个矢量，然后沿整个矢量找到最小值.

row and col would contain the row and column locations of matrix that are equal to this minimum value. Note that I had to unroll the matrix into a vector by doing matrix(:). The reason why is because if you were to use min on a matrix, it would by default give you the minimum along each column. Because you want to find the minimum over the entire matrix, you would convert this into a single vector, then find the minimum along the entire vector.

请注意，这将返回与最小值匹配的所有行和列位置，因此实际上会将row和col用作N x 1列向量，其中N是matrix中等于最小值的元素总数.

Take note that this will return all row and column locations that match the minimum, so it would actually give row and col as N x 1 column vectors, where N is the total amount of elements in matrix that equal the minimum.

如果您只想一个匹配，只需将1作为第二个参数附加到find:

If you only want one match, simply append a 1 as the second parameter to find:

[row, col] = find(matrix == min(matrix(:)), 1);

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