Re: How does Eigensystem works ?
- To: mathgroup at smc.vnet.net
- Subject: [mg103103] Re: How does Eigensystem works ?
- From: Alois Steindl <alois.steindl at jet2web.cc>
- Date: Tue, 8 Sep 2009 05:57:21 -0400 (EDT)
- References: <h829hp$3pk$1@smc.vnet.net>
guerom00 schrieb: > Hello everyone, > > If I compute the eigenvalues lambda and eigenvectors P of a square > matrix A, I get the original matrix back by calculating Transpose > [P].DiagonalMatrix[lambda].Transpose[Inverse[P]] ??? > > Now, I don't know much in linear algebra but I think I should get the > origonal matrix back by computing P.DiagonalMatrix[lambda].Inverse > [P] ! > > What gives? > > Thanks > Hello, that's, because {eval, evec}=Eigensystem returns the transpose of the matrix P in evec: The i-th element of evec contains the i-th eigenvector, whereas in A = P.diag(lambda).Inverse[P] one expects the i-th eigenvector in column i. Alois