How can I store the whole diagonal and not only the first element (For loop)

4 views (last 30 days)
Jonas Morgner
Jonas Morgner on 8 May 2022
Commented: VBBV on 8 May 2022
% Part 3.1: Diagonal
%A
rng('default')
r2 = randi(100,3,3); % Creating a 3x3 matrix, with random values from 1 to 100
%B
d = diag(r2) % Obtain the diagonal elements
%C
Metod1 = d(2,1) % Using two parameters (row 2, column 1)
Metod2 = d(3) % Using one parametr (3rd element)
%D
for K = 1 : size(d,1)
d(K,K)
end
I have a problem in storing the diagonal values of the Matrix. It somehow only stores the first entry of the diagonal, where instead it should store 3 entries in total. How can I change the for loop so it also stores the rest of the entries?
Also I get this error message when using the for loop:
"Index in position 2 exceeds array bounds. Index must not exceed 1"
What does it mean and how can I fix this?

Accepted Answer

VBBV
VBBV on 8 May 2022
% Part 3.1: Diagonal
%A
rng('default')
r2 = randi(100,3,3); % Creating a 3x3 matrix, with random values from 1 to 100
%B
d = diag(r2) % Obtain the diagonal elements
d = 3×1
82 64 96
%C
Metod1 = d(2,1) % Using two parameters (row 2, column 1)
Metod1 = 64
Metod2 = d(3) % Using one parametr (3rd element)
Metod2 = 96
%D
for K = 1 : size(d,1)
D(K,K) = d(K); % d matrix has only 3 rows , 1 col
end
D % declare/assign a new matrix which stores all elements of d into D diagonally.
D = 3×3
82 0 0 0 64 0 0 0 96
  2 Comments
VBBV
VBBV on 8 May 2022
You can simply use
D = d; % With out using loop
for K = 1 : size(d,1)
D(K,1) = d(K); % using loop
end

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by