Re: Updating Eigenvectors



Behjat wrote:
Hi,

I am looking for efficient methods of updating the eigenvectors when
the dimensions of the matrix is incremented.

Specifically, if I have a solution to the generalized eigenvalue
problem Ax = B $\lambda$ x with A and B of dimensions nxn. Now A and
B are updated to A' and B' of dimensions (n+1)x(n+1) by appending a
row, column and a diagonal element. Are there any efficient ways of
solving for A'x' = B' $\lambda'$ x'?

Thanks,
Behjat

Extend your known matrices A, B and your vector x trivially, by setting
A(n+1,n+1)=\lambda, B(n+1,n+1)=1, and, x(n+1)=1. Then treat A', B' as rank 1 perturbations of your extended A, B.

I can not point you to the right algorithm, as it is a bit outside my field, but googling "low rank perturbation +eigenvalue problem", looks promising.

Ah, I see Spellucci has already answered this question

http://www.math.niu.edu/~rusin/known-math/01_incoming/SVD_update

/CCKM
.



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    ... I am looking for efficient methods of updating the eigenvectors when ... the dimensions of the matrix is incremented. ... if I have a solution to the generalized eigenvalue ...
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  • Updating Eigenvectors
    ... I am looking for efficient methods of updating the eigenvectors when ... the dimensions of the matrix is incremented. ... if I have a solution to the generalized eigenvalue ...
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  • Updating Eigenvectors
    ... I am looking for efficient methods of updating the eigenvectors when ... the dimensions of the matrix is incremented. ... if I have a solution to the generalized eigenvalue ...
    (sci.math.num-analysis)