Compare big matrices A ,B
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I Have 2 big matrix A, B with the same dimension (mxn) that n>>m. I apply the princomp function on those for computing the principal components because I wanted to reduce those dimension for comparing those with each other. I want to find that which row of those matrices has biggest difference with each other. Is it possible by comparing the angles between the eigenvectors that I computed by the princomp function (principal components of the 2 matrix)?? It really appreciated if you get me some proposal and help. Thank you for your time and help. Kamal
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Image Analyst
on 23 Nov 2013
I agree with Jan - I'm confused too. After you do PCA on A and on B, you'll have two more sets of axes (one for each PC set on A and B) Are you comparing rows of A to rows of A? And same for B? Or are you comparing rows of A to rows of B? Or the angle between PC1 of A with PC2 of A? Or PC1 of A with PC1 of B? Please clarify.
Answers (1)
Image Analyst
on 23 Nov 2013
Edited: Image Analyst
on 23 Nov 2013
Try this
comparison = abs(A-B);
[maxValue, indexOfMax] = max(comparison);
% Get row and column from linear index.
[row, col] = ind2sub(size(A), indexOfMax);
How does that work for you?
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