Modified power iterations in existing SSVD code
-----------------------------------------------
Key: MAHOUT-796
URL: https://issues.apache.org/jira/browse/MAHOUT-796
Project: Mahout
Issue Type: Improvement
Components: Math
Affects Versions: 0.5
Reporter: Dmitriy Lyubimov
Assignee: Dmitriy Lyubimov
Fix For: 0.6
Nathan Halko contacted me and pointed out importance of availability of power
iterations and their significant effect on accuracy of smaller eigenvalues and
noise attenuation.
Essentially, we would like to introduce yet another job parameter, q, that
governs amount of optional power iterations. The suggestion how to modify the
algorithm is outlined here :
https://github.com/dlyubimov/ssvd-lsi/wiki/Power-iterations-scratchpad .
Note that it is different from original power iterations formula in the paper
in the sense that additional orthogonalization performed after each iteration.
Nathan points out that that improves errors in smaller eigenvalues a lot (If i
interpret it right).
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
