Re: What's up with the order of Eigenvalues
- To: mathgroup at smc.vnet.net
- Subject: [mg105825] Re: [mg105786] What's up with the order of Eigenvalues
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Sun, 20 Dec 2009 06:56:30 -0500 (EST)
- Reply-to: hanlonr at cox.net
According to the Eigenvalues documentation:
"If they are numeric, eigenvalues are sorted in order of decreasing absolute value."
It did what it said that it would do.
Bob Hanlon
---- mokambo <alexandrepassosalmeida at gmail.com> wrote:
=============
Dear all,
Consider a circulant matrix,
m = {{0, 1, 1, 0}, {0, 0, 1, 1}, {1, 0, 0, 1}, {1, 1, 0, 0}}
The eigenvalues of m are:
Eigenvalues[m]
= {2, -1 + I, -1 - I, 0}
But they should be equal to the Discrete Fourier Transform of the
first row of m
Fourier[{0, 1, 1, 0}, FourierParameters -> {1, -1}]
= {2 + 0.I, -1 - 1.I, 0 + 0.I, -1. + 1. I}
So what's up with the order of values given by Eigenvalues[]?
--
Bob Hanlon