Eigenvalues Okay, Eigenvectors Fail
- To: mathgroup at smc.vnet.net
- Subject: [mg88096] Eigenvalues Okay, Eigenvectors Fail
- From: jfuite at phys.ualberta.ca
- Date: Thu, 24 Apr 2008 05:58:36 -0400 (EDT)
Dear Mathematica Adepts,
I seek the eigenvectors and corresponding eigenvalues of a large
matrix of real values, m, such that, Union[Head /@ Flatten[m]]] =
{Real}. So far I have no trouble with this for matrices up to n x n,
n > 1300 using the function Eigensystem with very fast results. But,
sometimes, when I analyze transformed submatrices (mSub) of my
original matrix, where n' < 1300, the function, Eigensystem, fails to
produce output. Further, Eigenvalues[mSub], quickly produces a valid
list of n' eigenvalues, but, Eigenvectors[mSub] fails to complete.
Therefore I ask, "What is happening such that I can calculate a
complete list of n' eigenvalues for a real matrix, mSub, but I cannot
calculate the corresponding eigenvectors?"
I appreciate any thoughts on this. I use Mathematica 5.1.0.0 on MacOS
X 10.5.2.