vectorized non-linear matrix assignment

8 vues (au cours des 30 derniers jours)
cmo
cmo le 18 Mai 2015
Commenté : John D'Errico le 18 Mai 2015
Let A be an m x n matrix (both m,n > 1).
let "X" p-by-1 be a set of row indices of A, and "Y" p-by-1 be a set of column indices of "A".
Suppose I want to assign the values of vector "V" p-by-1 to coordinates "(X,Y)" of "A".
Is there a way to vectorize this assignment?
e.g.
A = zeros(10,10);
X = [1 4 5 9];
Y = [ 2 2 1 8];
V = [1.1 2.98 -3 14];
i.e.
I want to assign A(1,2) = 1.1 and A(4,2) = 2.98 and A(5,1) = -3 and A(9,8) = 14.
something like "A(X,Y) = V", but that doesnt work.

Réponses (1)

Star Strider
Star Strider le 18 Mai 2015
Using the sub2ind function is the easiest way:
LI = sub2ind(size(A), X', Y');
A(LI) = V
  1 commentaire
John D'Errico
John D'Errico le 18 Mai 2015
+1. While this is of course the correct answer, it has always bothered me that there is not a more direct solution. Use of sub2ind is just too un-obvious to the new user.

Connectez-vous pour commenter.

Catégories

En savoir plus sur Mathematics dans Help Center et File Exchange

Tags

Community Treasure Hunt

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

Start Hunting!

Translated by