I want to create a following matrix using nested loops

Matrix[1,2,3,4,5;2,4,7,11,16;3,7,14,25,41] Here every row has different logic.How do I use for loop?

[Rik]

Why do you want to use for loops exactly? What pattern is in this matrix?

[Walter Roberson]

it would make more sense to me if the last entry was 40 instead of 41...

Answer 1

[Image Analyst]

Here is another way where you're not starting with some initial matrix but just starting with an initial matrix of all zeros.

rows = 3;
columns = 5;
Matrix = zeros(rows, columns); % Initialize
for row = 1 : rows
    if row == 1
        for col = 1 : columns
            Matrix(row, col) = col;
        end
    else
        for col = 1 : columns
            if col == 1
                Matrix(row, col) = row;
            else
                Matrix(row, col) = Matrix(row, col - 1) + Matrix(row-1, col);
            end
        end
    end
end
Matrix

Matrix = 3×5

1 2 3 4 5 2 4 7 11 16 3 7 14 25 41

[Shivani Galande]

Thank you so much. I was struggling with if loop.

Answer 2

[Sam Chak]

@Shivani Galande

I'm no good at nested math. Please write the math equations to describe the relationship between the elements of the matrix.

The general idea is to populate the zero matrix in loops

M = zeros(3, 5)

M =

0 0 0 0 0

0 0 0 0 0

0 0 0 0 0

to become

M = [1 2 3 4 5; 2 4 7 11 16; 3 7 14 25 41]

M =

1 2 3 4 5

2 4 7 11 16

3 7 14 25 41

[Shivani Galande]

I'm not able to find out pattern between the columns.

[Sam Chak]

Hi @Shivani Galande

I can understand it is not easy at the beginning. But it is definitely something to train your cognitive skills in writing Loops and Conditionals.

If you want to challenge yourself, or at least make it a little extraordinary from your classmates, you can modify @Image Analyst's code to begin from the last ROW. You can submit two solutions.

Answer 3

[Image Analyst]

Here is one way:

Matrix = [1,2,3,4,5;
    2,4,7,11,16;
    3,7,14,25,41] 

Matrix = 3×5

1 2 3 4 5 2 4 7 11 16 3 7 14 25 41

rows = 3;
columns = 5;
m = Matrix; % Initialize
for row = 2 : rows
    for col = 2 : columns
        m(row, col) = Matrix(row, col - 1) + Matrix(row-1, col);
    end
end
m

m = 3×5

1 2 3 4 5 2 4 7 11 16 3 7 14 25 41

(IMPORTANT Note, if this is your homework you could get into trouble submitting my code as your own.)

Be sure to see my other answer where Matrix is all zeros to start with..

Note: You could also do this with the conv2 function.