PPS > not sure about numerical stability with 100% streaming though. if that turns out to be a problem, i can always go back to multiple Q blocks per mapper though to improve on it.
On Tue, Oct 26, 2010 at 12:27 PM, Dmitriy Lyubimov <[email protected]>wrote: > not sure about numerical stability with 100% streaming though. > > > > On Tue, Oct 26, 2010 at 12:22 PM, Dmitriy Lyubimov <[email protected]>wrote: > >> Just an update. >> >> I am still working out a version that would do 100% mapreduce version of Q >> orhonormalization . I think i made some progress with the prototype, and >> basically there seems also to be a way to drastically cut on the output of >> the first map reduce (i.e. reduce amount of partial B^t outer products) >> depending on how much one wants to compromise the stochastic effect produced >> by Y. The algorithm also significantly simplifies the orthogonolization >> process by basically getting rid of Y-blocking entirely inside the same >> mapper (i.e. it's 100% streaming, 1 Q-block per mapper with memory >> requirements still constant to size of a row of A). >> >> It's slow due to my family situtation (i had just several hours to work on >> non-mr prototype so far, which passed Q orthogonality test, everything else >> is just a thought experiment) >> >> >> On Sun, Oct 24, 2010 at 12:11 AM, Ted Dunning (JIRA) <[email protected]>wrote: >> >>> >>> [ >>> https://issues.apache.org/jira/browse/MAHOUT-376?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel] >>> >>> Ted Dunning updated MAHOUT-376: >>> ------------------------------- >>> >>> Attachment: sd.tex >>> sd.pdf >>> >>> Updated version. >>> >>> I think that this is actually a feasible algorithm. >>> >>> > 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, Modified stochastic svd >>> algorithm for mapreduce.pdf, sd-bib.bib, sd.pdf, sd.pdf, sd.pdf, sd.pdf, >>> sd.tex, sd.tex, sd.tex, 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. >>> >>> >> >
