I did not choose Lanczos. It found it being used as a part of Spectral-Kmeans implemented in Mahout. Can u please recommend some better alternative of Lanczos.
Thanks, Aniruddha -----Original Message----- From: Ted Dunning [mailto:[email protected]] Sent: Tuesday, July 31, 2012 6:24 PM To: [email protected] Cc: Jake Mannix Subject: Re: Mahout LanczosSolver explanation WHy are you using Lanczos? Why not use something more recent? On Tue, Jul 31, 2012 at 7:00 PM, Aniruddha Basak <[email protected]>wrote: > Hi, > I am working on Spectral Kmeans which involves an eigen-decomposition > step using Lanczos. As I did not get exact similar results as > expected, I tried to understand the implementation. > I have one question about "LanczosSolver .java" : > In the "solve" method, while building the "tridiagonal matrix" there > is a step just after the multiplication job (performed on Hadoop as > TimesSquaredJob) as > ------------ > nextVector.assign(new Scale(1.0 / state.getScaleFactor())); > ----------- > I could not understand why this scaling is performed? > > ( When I compared the results on a small matrix to an equivalent > Matlab script, I found the results are exactly similar WITHOUT this > scaling. Including this scaling makes the results different from the > Matlab results. ) > > > Thanks, > Aniruddha > >
