Produce matrix with loop

Hi! I have a homework problem that I have difficulties with.

The problem is asking me to create a m by n matrix, using a function file, whose elements are going to be the sum of the index of each element. For exemple my first column would be A(1,1)=2 A(2,1)=3 A(3,1)=4 and so on.. I also must use the ''for'' loop. I tried to figure out how am I going to solve this problem before typing anything in my script file, so I thought that I could assign a matrix composed of ones, and of the dimensions of my outpout argument like U=ones(m,n) so my index variable ''k'' in my for loop could give the right value of each one after each pass, but I can't figure out hiow can I do that.. Can you give me a hint ?

Thanks!

Answer 1

[Matt Fig]

Most people on here will not just do a whole homework assignment for you. If you don't do any work, you will not learn. I will show you most of the solution, and I bet you can easily fill in the rest. Be sure to study it so you understand.

function A = elems_sum(m,n)
% Put help here.  
for ii = 1:m
    for jj = 1:n
        A(ii,jj) = ??????;
    end
end

[Tom]

I'm sorry If I went too fast on the ''ask'' button I didn't know until now how could I use a nested loop. But be assured that I tried to find a way to write my script using my references. But thank you very much for your time. If I understand, the two for statements indicates that for the first pass ii will equal 1, until all the values of jj are passed; so in my function the loop does (1+1),(1+2) etc.. until ii=m, then the loops ends and I have my matrix.. Thanks again..

[Matt Fig]

Sounds like you got it. Good luck to you.

Answer 2

[chris hinkle]

Here's an idea, tell your teacher not to promote for loops and take advantage of matlabs strength in vectorized functions

Matr=ones(m, n); [y,x] = find(Matr > 0); indMat = y+x;

The less you use for loops the better!

[Matt Fig]

You could have just used find(Matr) without first doing the logical comparison. And I think you meant:

Matr=ones(m, n); [y,x] = find(Matr); Matr(:) = y+x

We can even do without using FIND all together:

A = cumsum([2:m+2;ones(n-2,m+1)])

[chris hinkle]

Good point matt, and yes I was just being sloppy just answered this on my phone!