CD & PCA-whitened

1) Why in CD learning if the weights get bigger we need more iterations of CD to get unbiased samples from the equilibrium distribution?

2) What is the PCA-whitening that is applied to the data as preprocessing?

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1 Response to “CD & PCA-whitened”


  1. 1 Pierre Luc Carrier April 11, 2013 at 12:24

    Q1 : Briefly, bigger weights => sigmoids units tend to saturate more => Markkov Chains tend to converge more => mixing between modes becomes harder.

    Q2 : PCA projects the data in a space where the attributes are uncorrelated. PCA-Whitening does PCA + ensure that the attributes in the PCA space have unit variance.


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