Introduction to Matlab Coursera Minimum and Maximum Assignment

Having some trouble with this assignment.

Write a function called minimax that takes M, a matrix input argument and returns mmr, a row vector containing the absolute values of the difference between the maximum and minimum valued elements in each row. As a second output argument called mmm, it provides the difference between the maximum and minimum element in the entire matrix. See the code below for an example:

>> A = randi(100,3,4)
A =
    66    94    75    18
     4    68    40    71
    85    76    66     4
>> [x, y] = minimax(A)
x =
    76    67    81
y =
    90
    %Code to call your function
    [mmr, mmm] = minimax([1:4;5:8;9:12])

[Ayush Anand]

mmr = (max(A,[],2)-min(A,[],2))'

mmm = max(A,[],"all")-min(A,[],"all");

[Jacob]

Is there a simpler way of doing this? Coursera has not yet covered some of the code you used.

[Umar]

Hi Jacob, A simpler way to implement this code in Matlab would be

function [mmr, mmm] = minimax(M)

    % Find the maximum value in each row of matrix M

    max_per_row = max(M, [], 2);

    % Find the minimum value in each row of matrix M

    min_per_row = min(M, [], 2);

    % Calculate the range (max-min) for each row

    mmr = abs(max_per_row - min_per_row);

    % Calculate the overall range (max-min) for the entire matrix

    mmm = max(M(:)) - min(M(:));

end

So, function named minimax that takes a matrix M as input and returns two outputs: mmr (range for each row) and mmm (overall range for the entire matrix). The function first finds the maximum and minimum values in each row of the matrix and then calculates the range values accordingly

Hope this will help resolve your issue.

[Jacob]

Thanks, that makes a lot more sense. But the max_per_row and min_per_row will have to be the prime version, right? Since the question asks for a row vector and "max" and "min" return a column vector.

[Umar]

Hi Jacob, To address your concern about `max_per_row` and `min_per_row` being column vectors instead of row vectors, you are correct in pointing out that the current implementation returns column vectors. To ensure that these values are row vectors as per the requirement, you can transpose them to convert from column vectors to row vectors.