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From Jake Mannix <jake.man...@gmail.com>
Subject Re: lanczos problem
Date Thu, 15 Apr 2010 14:14:45 GMT
Hi Young,

  The test we do currently, to verify correctness, is to take the purported
eigenvectors
and simply check how far off from eigen-ness they are, as well as verify all
of the
eigenvectors are orthonormal.

  See org.apache.mahout.math.hadoop.decomposer.EigenVerificationJob for how
we do cleanup and verification of a eigen extraction.

  -jake

On Wed, Apr 14, 2010 at 10:52 PM, Young Y Kim <yoong02@gmail.com> wrote:

> i'm testing my LanczosSolver and i'm having problems validating the result.
> if i'm not mistaken, V^T * A * V should equal T (from
> http://en.wikipedia.org/wiki/Lanczos_algorithm) but my
> LanczosSolver is producing a completely different result.
> how do i check if the resulting eigenvalues are correct?
>
> I've used the basis as V and triDiag as T in solver function. is that
> correct?
>

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