On Monday 19 February 2007 12:06, Sven Schreiber wrote: > Zachary Pincus schrieb: > > Hello all, > > > > It seems that the 'eigh' routine from numpy.linalg does not follow > > the same convention as numpy.linalg.eig in terms of the order of the > > returned eigenvalues. (And thus eigenvectors as well...) > > I was told on this list that the ordering should not be relied upon, and > that it might change in the future. So it seems that user code should > explicitly re-order the eigenvalues (and corresponding eigenvectors, > probably using argsort and fancy indexing -- if those are the right terms).
Indeed. eig and eigh are wrappers for lapack functions, so the result is whatever those give back. Do not rely on a particular order of eigenvalues, sort yourself. Short example for convenience: #--------- eigvals, eigvecs = eig(some_matrix) ind = argsort(eigvals) eigvals = eigvals[ind] eigvecs = eigvecs[:, ind] # second axis !! # etc. #------------ Johannes _______________________________________________ Numpy-discussion mailing list Numpy-discussion@scipy.org http://projects.scipy.org/mailman/listinfo/numpy-discussion
