[SciPy-user] linalg.eig
Pearu Peterson
pearu at cens.ioc.ee
Thu Sep 19 11:49:50 EDT 2002
On Thu, 19 Sep 2002, Nils Wagner wrote:
> Hi,
>
> To finish the discussion on linalg.eig ...
>
> w, vl, vr = linalg.eig(A,B,left=1,right=1)
>
> Please correct me, but I guess that the output of
> linalg.eig(A,B,left=1,right=1)
> is as follows
>
> vr are the right eigenvectors
>
> but vl are the complex c o n j u g a t e left eigenvectors
Yes, you are right. This is also what linalg.eig.__doc__ says.
Note that linalg.eig uses LAPACK convention. In matrix notation, we have
w, vl, vr = linalg.eig(a,b,left=1,right=1)
such that
a * vr = d * b * vr
a^H * vl = d^H * b^H * vl or vl^H * a = d * vl^H * b
where `*' denotes matrix multiplication and d is a diagonal matrix of
eigenvalues: d = diag(w).
Pearu
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