Vector has both dot() and cross() products. Are you looking at the latest .diff?
I can easily move the vector package stuff back into matrix. It used to be there and I moved it into its own package just to "organize" it better. You are correct; however, that having them in the same package would allow protected methods to be shared between the implementations. Moving all the matrix and vector operations into org.apache.mahout.matrix is also worth discussing. I can see its importance is, perhaps, more than just as a utility. Jeff -----Original Message----- From: Jason Rennie (JIRA) [mailto:[EMAIL PROTECTED] Sent: Friday, March 07, 2008 1:00 PM To: mahout-dev@lucene.apache.org Subject: [jira] Commented: (MAHOUT-6) Need a matrix implementation [ https://issues.apache.org/jira/browse/MAHOUT-6?page=com.atlassian.jira.p lugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12576371#a ction_12576371 ] Jason Rennie commented on MAHOUT-6: ----------------------------------- Re: Jeff Sounds good. It think I might actually have some time to do this. One thing I didn't see when looking through the last patch was basic matrix/vector operations. I'll go ahead and include a dot-product method to exhibit how it'd work and do some speed comparisons vs. a HashMap impl. Yeah, would definitely be good to get this stuff in trunk, if only to make it easier to read/access! :) Re: Ted Didn't realize HashMaps were so fast. Will be good to revisit the testing I did earlier. Agreed on the CRS benefits. One way I get around the sorted constraint while constructing a sparse vector is a SparseVectorBuilder class. It basically has two methods: void add(int _idx, double _val), and SparseVector build(). Avoids having to keep state within the SparseVector. > Need a matrix implementation > ---------------------------- > > Key: MAHOUT-6 > URL: https://issues.apache.org/jira/browse/MAHOUT-6 > Project: Mahout > Issue Type: New Feature > Reporter: Ted Dunning > Attachments: MAHOUT-6a.diff, MAHOUT-6b.diff, MAHOUT-6c.diff, MAHOUT-6d.diff, MAHOUT-6e.diff, MAHOUT-6f.diff, MAHOUT-6g.diff, MAHOUT-6h.patch, MAHOUT-6i.diff, MAHOUT-6j.diff > > > We need matrices for Mahout. > An initial set of basic requirements includes: > a) sparse and dense support are required > b) row and column labels are important > c) serialization for hadoop use is required > d) reasonable floating point performance is required, but awesome FP is not > e) the API should be simple enough to understand > f) it should be easy to carve out sub-matrices for sending to different reducers > g) a reasonable set of matrix operations should be supported, these should eventually include: > simple matrix-matrix and matrix-vector and matrix-scalar linear algebra operations, A B, A + B, A v, A + x, v + x, u + v, dot(u, v) > row and column sums > generalized level 2 and 3 BLAS primitives, alpha A B + beta C and A u + beta v > h) easy and efficient iteration constructs, especially for sparse matrices > i) easy to extend with new implementations -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.
