PCA for spectral data
Hello, I am performing a PCA on a large data set (257 columns (wavenumber) and about 8000 rows (samples)) and want to recognise certain patterns between the spectra with the PCA.
However, this warning always appears ‘Warning: The matrix correlation is not positive definite.’ Can someone help me to understand what this means and if it is relevant for my analysis of the data? I am only a beginner in ...