Finding unique slices of a multidimensional array
8 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Jake Martin
il 20 Nov 2020
Commentato: the cyclist
il 20 Nov 2020
I'm trying to find unique slices of a multi-dimensional array. For example, if I have something like
A = repmat(magic(4),1,1,3);
A(:,:,2) = A(:,:,2) - 1
A(:,:,1) =
16 2 3 13
5 11 10 8
9 7 6 12
4 14 15 1
A(:,:,2) =
15 1 2 12
4 10 9 7
8 6 5 11
3 13 14 0
A(:,:,3) =
16 2 3 13
5 11 10 8
9 7 6 12
4 14 15 1
I would like to be able to call something (with the dimension along which I'm slicing specified) and get
[C, ia, ic] = highdim_unique(A, 3)
C(:,:,1) =
16 2 3 13
5 11 10 8
9 7 6 12
4 14 15 1
C(:,:,2) =
15 1 2 12
4 10 9 7
8 6 5 11
3 13 14 0
ia =
1
2
ic =
1
2
1
Any chance that something like this exists or has a straightforward solution? Ideally I would want to do this for arbitrariliy many dimensions, but doing it in 3 would be fine.
Thanks,
Jake
0 Commenti
Risposta accettata
the cyclist
il 20 Nov 2020
% Define a 3-d array of pretend data, that has a couple duplicate slices
% (Use your data instead)
rng default
A = rand(2,2,4) > 0.5;
% Find the size of A, for generality
[s1,s2,s3] = size(A);
% Reshape the slices into rows (by working down column-wise, and then across columns)
A_r = reshape(A,s1*s2,s3,1)';
% Find the unique rows (which corresponds to unique slices of original array)
A_ru = unique(A_r,'rows','stable');
% Reshape the rows back to 3-d
A_u = reshape(A_ru',s1,s2,[]);
2 Commenti
the cyclist
il 20 Nov 2020
Excellent.
I didn't really think about how to do it for N-dimensional array for N>3, but I see no reason why you could not do the same "reshape into rows" method.
Più risposte (0)
Vedere anche
Categorie
Scopri di più su Creating and Concatenating Matrices in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!