I'm pretty sure that the COLT code does it in reverse order (see LanczosSolver for some usage there).
-jake On Sun, Oct 10, 2010 at 7:00 AM, Ted Dunning <[email protected]> wrote: > Cool. > > I previously potted and tested the qr decomposition. Looks I have a similar > task ahead for the svd. > > It us the convention that the singular values come out in order but there > is usually no guarantee that the will so the svd codes usually have a sort > step to do this. > > Sent from my iPhone > > On Oct 9, 2010, at 10:09 PM, "Dmitriy Lyubimov (JIRA)" <[email protected]> > wrote: > > > > > [ > https://issues.apache.org/jira/browse/MAHOUT-376?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12919567#action_12919567] > > > > Dmitriy Lyubimov edited comment on MAHOUT-376 at 10/10/10 1:08 AM: > > ------------------------------------------------------------------- > > > > ok, i got to BBt normalized for rank deficiences in Q blocks. > > > > What eigensolver should i use in context of Mahout? I know there's > something in that Cern library but it is all deprecateed. There's also a > solver in apache commons, but it is not readily imported into the mahout > core. > > > > Thanks. > > > > PS. i tried EigenvalueDecomposition from cern library. I know i am quite > likely providing an ill-conditioned matrix in my unit test but strange thing > is that eigen values are not always in descending order. i thought they were > supposed to come out in descending order? > > > > was (Author: dlyubimov2): > > ok, i got to BBt normalized for rank deficiences in Q blocks. > > > > What eigensolver should i use in context of Mahout? I know there's > something in that Cern library but it is all deprecateed. There's also a > solver in apache commons, but it is not readily imported into the mahout > core. > > > > Thanks. > > > >> Implement Map-reduce version of stochastic SVD > >> ---------------------------------------------- > >> > >> Key: MAHOUT-376 > >> URL: https://issues.apache.org/jira/browse/MAHOUT-376 > >> Project: Mahout > >> Issue Type: Improvement > >> Components: Math > >> Reporter: Ted Dunning > >> Assignee: Ted Dunning > >> Fix For: 0.5 > >> > >> Attachments: MAHOUT-376.patch, sd-bib.bib, sd.pdf, sd.tex, > Stochastic SVD using eigensolver trick.pdf > >> > >> > >> See attached pdf for outline of proposed method. > >> All comments are welcome. > > > > -- > > This message is automatically generated by JIRA. > > - > > You can reply to this email to add a comment to the issue online. > > >
