what does it mean by [ ] in the following code

min(N,[],3)

Answer 1

[ANKUR KUMAR]

It returns a column vector containing the smallest element in each row along third dimension.

Read this for more details https://in.mathworks.com/help/matlab/ref/min.html

Answer 2

[Star Strider]

In the min function, the second argument is usually the second numerical scalar value to be compared. If you only have one argument, for example a matrix, and you want to find the minimum in a specific dimension of the matrix, leave the second argument ‘empty’ with the ‘empty array’ denoted by [], and then use a dimension argument.

In a function call, all arguments must appear in the correct order.

So here:

min(N,[],3)

the function takes the minimum of matrix ‘N’ along the third dimension, leaving the second argument ‘empty’.