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Subject: Re: Eigenvectors with Identical Eigenvalues Lose orthogonality?
Date: Fri, 6 Aug 2010 16:54:04 +0000 (UTC)
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"NIcholas " <dsfadfa@aol.com> wrote in message <i3hcrc$g9o$1@fred.mathworks.com>...
> Shouldn't the command "[V,D] = eig(A);" give an orthogonal basis V?
==============

If A is not Hermitian, it might not even have a fulll set of linear independent eigenvectors, making it impossible for eig() to produce an orthogonal basis.

In your example, A is Hermitian, but since eig doesn't know this in advance, it has no reason to try to orthogonalize the result.