find the signed minimum value in a three dimensional matrix in MATLAB

Question

I have a 3D matrix d and I want to find the signed minimum value along the third dimension. Currently, I use following code

tmp = abs(d);
[row, col]=ndgrid(1:size(d,1),1:size(d,2));

[v,ind] = min(tmp,[],3); 
index = row + size(d,1)*size(d,2)*(ind-1)+ size(d,1)*(col-1); %turn the ind to index
dm = d(index); %get the signed minimum value

The above code does not so efficient. Does anyone know a better choice? Thank you!

Answer 1

无需创建row和col值的网格以将ind转换为可用于索引回d索引，您只需使用min的第一个输出即可，该输出包含第三个维度上的最小值。

dm = min(abs(d), [], 3);