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Topic: Question about Principal Component Analysis (PCA) results.
Replies: 1   Last Post: Nov 6, 2012 2:25 PM

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Aaronne

Posts: 110
Registered: 6/2/11
Question about Principal Component Analysis (PCA) results.
Posted: Nov 6, 2012 8:57 AM
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Currently, I am a little bit confusing about Principal Component Analysis (PCA) results and in which way I can use PCA.

For example, I have got some spectral signal of waves. They are digitised by 2,000 sampling points of each wave. And the training data set contains 500 of such waves.

I store this data set in a 2,000 by 500 matrix.

Then I run the PCA program on the data set, and I want to get 3 PCs only. My question is:

What results should I get?

I think it should produce a 2,000 by 3 matrix and each column of the result matrix is a PC. Am I right?

For example, I use Matlab based fastica package to do the PCA, A is the original 2,000 by 500 matrix,

Should I do:

numberofPC = 3;

[PCs, eigenVal] = fastica(A, 'lastEig', numberofPC, 'only', 'pca');

or

[PCs, eigenVal] = fastica(A', 'lastEig', numberofPC, 'only', 'pca');

???

Thanks very much.



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