Row product and column product

5. Recall that if A is an m n matrix and B is a p q matrix, then the product C = AB is denoted if and only if n = p, in which case C is an m q matrix.

(a) Write a function M-file that takes as input two matrices A and B, and as output produces the product by columns of the two matrix. For instance, if A is 3x4 and B is 4x5, the product is given by the matrix C = [A*B(:,1), A*B(:,2), A*B(:,3), A*B(:,4), A*B(:,5)]The function file should work for any dimension of A and B and it should perform a

check to see if the dimensions match (Hint: use a for loop to denote each column of C). Call the file columnproduct.m.Test your function on a random 5x3 matrix A and a random 3x5 matrix B . Compare the output with A*B. Repeat with 3 x 6 and 6 x 4 matrices and with 3 x 6 and 4 x 6 matrices.Use the command rand to generate the random matrices for testing. Include in your lab report the function M-file and the output obtained by running it.

(b) Write a function M- file that takes as input two matrices A and B, and as output produces the product by rows of the two matrices. For instance, if A is 3 x 4 and B is 4x5, the product AB is given by the matrix C = [A(1,:)*B; A(2,:)*B; A(3,:)*B] The function file should work for any dimension of A and B and it should perform a check to see if the dimensions match (Hint: use a for loop to denote each row of C). Call the file rowproduct.m. Test your function on a random 5x3 matrix A and a random 3x5 matrix B . Compare the output with A*B. Repeat with 3 x 6 and 6 x 4 matrices and with 3 x 6 and 4 x 6 matrices. Use the command rand to generate the random matrices for testing.

Include in your lab report the function M-file and the output obtained by running it.

[the cyclist]

Quoting Steven Lord, in the other homework problem you posted:

Because this is a homework assignment, please show us the code you've written to try to solve the problem and ask a specific question about where you're having difficulty and we may be able to provide some guidance.

If you aren't sure where to start because you're not familiar with how to write MATLAB code, I suggest you start with the MATLAB Onramp tutorial (https://www.mathworks.com/support/learn-with-matlab-tutorials.html) to quickly learn the essentials of MATLAB.

If you aren't sure where to start because you're not familiar with the mathematics you'll need to solve the problem, I recommend asking your professor and/or teaching assistant for help.

[Tyler Bates]

This is how my code looks. I would just like to verify it is correct. I duplicated it and changed m and n to comply with assignment for the other 2 parts.

function C=rowproduct1(A,B)
m=5;n=2;
A=floor(rand(m,n)*10);
B=floor(rand(n,1)*10);
[a,b]=size(A);
[p,q]=size(B);
if(p==b)
    C=zeros(a,q);
    for i=1:m
        C(i,:)=A(i,:)*B
    end
else 
    disp('Size mismatch check input!')
    C=[];
end
end

[Steven Lord]

Your code is not correct. You receive A and B from the user of your function (likely your professor) then promptly discard the A and B matrices you received as input and create your own random ones. Just use the matrices you were given.

Once you've corrected that problem, try calling your function with (small) A and B inputs for which you know or can manually compute the correct answer, and see if your function returns the answer you expect. Each time you receive the known / manually computed correct answer, that increases your confidence that your code is correct. If it doesn't return the answer you expect debug the code by stepping through it, section by section or line by line. Then if you made a change to fix the bug, rerun your previous test cases to make sure you haven't broken something that was working previously.