Combine arrays to form another arrays

1 vue (au cours des 30 derniers jours)
Ellina
Ellina le 9 Sep 2014
Commenté : Andrei Bobrov le 9 Sep 2014
Hello, can we combine many arrays into another arrays?
for example:
k = 5;
for u=1:k
H(:,:,u)=randn(M,N)+j*randn(M,N);
end
for u=1:k
Hi(:,:,1)=[H(:,:,2);H(:,:,3);H(:,:,4);H(:,:,5)];
Hi(:,:,2)=[H(:,:,1);H(:,:,3);H(:,:,4);H(:,:,5)];
Hi(:,:,3)=[H(:,:,1);H(:,:,2);H(:,:,4);H(:,:,5)];
Hi(:,:,4)=[H(:,:,1);H(:,:,2);H(:,:,3);H(:,:,5)];
Hi(:,:,5)=[H(:,:,1);H(:,:,2);H(:,:,3);H(:,:,4)];
end
what if k=19, should I repeat all the steps. Are there other simpler programs to combine it. Thank you
  1 commentaire
Pierre Benoit
Pierre Benoit le 9 Sep 2014
What is the relation between the number of arrays you wish to concatenate each time and k ? Is it always 4, or k-1 or something else ?

Connectez-vous pour commenter.

Connectez-vous pour répondre à cette question.

Réponse acceptée

Guillaume
Guillaume le 9 Sep 2014
H = randn(M, N, k) + j*randn(M, N, k); %no need for loop
c = num2cell(H, [1 2]); %split H into cell array along 3rd dimension
for u=1:k
indices = [1:u-1 u+1:k]; %get numbers 1:k without u
Hi(:, :, u) = vertcat(c{indices}); %use cell array to comma separated list expansion to feed vertcat
end
  1 commentaire
Ellina
Ellina le 9 Sep 2014
It's work. Thank you so much. :-)

Connectez-vous pour commenter.

Plus de réponses (1)

Pierre Benoit
Pierre Benoit le 9 Sep 2014
Modifié(e) : Pierre Benoit le 9 Sep 2014
M = 5;
N = 5;
k = 5;
H = randn(M, N, k) + j*randn(M, N, k);
permut = nchoosek(1:k,k-1); % Find all permutations
permut = permut(end:-1:1,:); % Flip array
Hi = reshape(permute(reshape(H(:,:,permut'),[M N k-1 k]),[1 3 2 4]),
[M*(k-1) N k]);
Or with a for-loop to be more explicit
Hi = zeros(M*(k-1),N,k); % Pre-allocation
for ii = 1:k-1
Hi(:,:,ii) = reshape(permute(H(:,:,permut(ii,:)),[1 3 2]),[M*(k-1) N]);
end
  1 commentaire
Andrei Bobrov
Andrei Bobrov le 9 Sep 2014
variant
M = 4;
N = 3;
k = 5;
H = randn(M, N, k) + 1i*randn(M, N, k);
p = flipud(nchoosek(1:k,k-1));
Tout = permute(reshape(permute(H(:,:,p),[1 3 2]),[],k-1,N),[1 3 2]);

Connectez-vous pour commenter.

Catégories

En savoir plus sur Linear Algebra 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