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Am I correct to understand from the previous discussions on this topic (a few years back) that if I have a matrix with missing values my PCA options seem dismal if: (1) I don’t want to impute the missing values. (2) I don’t want to completely remove cases with missing values. (3) I do cov() with use=”pairwise.complete.obs”, as this produces negative eigenvalues (which it has in

Dear all, I'm looking for users of the hyperSpec package for handling (hyper)spectral or spectroscopic data in R which I maintain. First of all, I made a few announcements concerning the further development which can be found in the hyperSpec-help mailing list an on which I hope to get user feedback: see http://lists.r-forge.r-project.org/pipermail/hyperspec-help/2012-July/thread.html. My