Vectorization in more than two dimensions

Is there a way to use vectorized operations in more than two dimensions? For example, in the following code I want to create a three-dimensional matrix based off a function in three variables. I am able to vectorize in two dimensions using the transpose function, but for the third dimension I use a for loop. Is there a way to eliminate the loop?
x=1:1000;x=x';
y=1:586;
z=1:247;
U=zeros(length(x),length(y),length(z));
for cnt=1:length(z)
U(:,:,cnt)=(x.^2+y.^3*z(cnt)).*exp(x*z(cnt).^2).*besselj(0,y);
end

1 comentario

I think I figured out a solution. If there is a more elegant way, I am all ears. I want to extend this to five dimensions, and keeping track of the permutations is going to be tricky.
x=1:5;
y=1:6;
z=1:3;
X=repmat(x',[1 length(y) length(z)]);
Y=repmat(y,[length(x) 1 length(z)]);
Z=repmat(z,[length(x) 1 length(y)]);Z=permute(Z,[1 3 2]);
U=(X.^2+Y.^3.*Z).*exp(X.*Z.^2).*besselj(0,y);

Iniciar sesión para comentar.

Respuestas (1)

Walter Roberson
Walter Roberson el 25 de Nov. de 2020
Editada: Walter Roberson el 25 de Nov. de 2020
X = reshape(1:5, [], 1, 1);
Y = reshape(1:6, 1, [], 1);
Z = reshape(1:3, 1, 1, []);
U = (X.^2+Y.^3.*Z).*exp(X.*Z.^2).*besselj(0,Y);
size(U)
ans = 1×3
5 6 3
Need R2016b or later.

2 comentarios

Jan
Jan el 25 de Nov. de 2020
This is much more efficient then expanding the arrays. besselj is expensive. Then expanding the argument wastes a lot of time with calculating the results for the same inputs.
Nicole Brimhall
Nicole Brimhall el 25 de Nov. de 2020
Thank you. That was very helpful.

Iniciar sesión para comentar.

Productos

Versión

R2020b

Preguntada:

el 25 de Nov. de 2020

Comentada:

el 25 de Nov. de 2020

Community Treasure Hunt

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

Start Hunting!

Translated by