how create a new matrix with values found in an another matrix
5 views (last 30 days)
Show older comments
Hi, I've the matrix A with dimension (m*n*p). I've found the indexes of the first non-zero elements along the dimension p. They are stored in I with dimension m*n. I would create a new matrix B with dimension m*n with the values corresponding to the indexes I taken in A.
Thanks, Gianluca
2 Comments
Accepted Answer
Sven
on 23 Sep 2012
Edited: Sven
on 23 Sep 2012
Hi Gianluca,
Have you tried using the second output from find_ndim?
[I, Imap] = find_ndim(A,3,'first');
B = A(Imap); % The actual elements of A that were "found" above, as a vector
B = reshape(B, size(I)); % size(I) is just [m n] from your question
Basically, the elements of the variable I (output from find_ndim) are the subscript references of the 3rd dimension of A. You can also use sub2ind() to get the same result as above, you just also need the first and second subscript references:
[subs2ndDim,subsFirstDim] = meshgrid(1:size(A,2),1:size(A,1));
inds = sub2ind(size(A), subsFirstDim, subs2ndDim, I)
B = A(inds);
Hope this helped you out.
0 Comments
More Answers (0)
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!