creating a data array from a matrix
7 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Hi,
I have matrix1 of 39 x 39. I need to create X and Y arrays by reading elements from rows and columns of matrix1 in a certain way.
X Y
(2,1) (1,2)
(3,1) (1,3)
(4,1) (1,4)
..
(39,1) (1,39)
(3,2) (2,3)
(4,2) (2,4)
..
(39,2) (2,39)
(4,3) (3,4)
..
(39,3) (3,39)
..
(39,38) (38,39)
How can I implement in MATLAB? Can somebody help me.
Thanks in advance,
0 commentaires
Réponse acceptée
Geoff Hayes
le 30 Mai 2014
Modifié(e) : Geoff Hayes
le 30 Mai 2014
Hi Damith - I'd go with a double for loop, pre-allocating memory for the X and Y vectors:
[m,n] = size(matrix1); % where matrix1 is the 39x39 matrix
numElems = (m-1)*m/2; % since ignoring elements on matrix diagonal
X = zeros(numElems,1);
Y = X;
at = 1;
for i=1:m
for j=i+1:m % since not interested in i==j
X(at) = matrix1(j,i);
Y(at) = matrix1(i,j);
at = at + 1;
end
end
Plus de réponses (1)
Udit Gupta
le 30 Mai 2014
This is simple if you use matlab lower triangle functions. See the example code below please.
A = magic(39) % Your Martix
mask = tril(true(39),-1);
X = A(mask);
B = A';
Y = B(mask);
2 commentaires
Voir également
Catégories
En savoir plus sur Creating and Concatenating Matrices dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!