[mlpack-svn] [MLPACK] #355: kernelPCA centering
MLPACK Trac
trac at coffeetalk-1.cc.gatech.edu
Thu Jun 26 10:26:40 EDT 2014
#355: kernelPCA centering
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Reporter: Niteloser | Owner:
Type: defect | Status: new
Priority: major | Milestone:
Component: mlpack | Keywords:
Blocking: | Blocked By:
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I have had a look at the kernelPCA source code. When you centre a kernel
matrix, should
arma::sum(kernelMatrix, 1) / kernelMatrix.n_cols;
not be computed before you subtract the means from the rows in the
previous line?
I seem to be getting inconsistent results when using it, with the first PC
disagreeing
with alternative implementations, but then agreeing from the second PC
onwards. This seems like a tell-tale sign of centring going wrong.
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Ticket URL: <https://trac.research.cc.gatech.edu/fastlab/ticket/355>
MLPACK <www.fast-lab.org>
MLPACK is an intuitive, fast, and scalable C++ machine learning library developed at Georgia Tech.
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