Hi Jonathan, Here's what u gotta do to run RowSimilarity on ur CSV formatted data. You would have to use the MapReduce version since the Spark version only supports LLR.
1. Convert CSV to Vectors - use CSVIterator and store the vectors as SequenceFiles 2. Run RowIDJob on the SequenceFile output of (1). This should generate a Matrix of <IntWritable, VectorWriteable> and a docIndex of <IntWritable, Text> 3. Run RowSimilarityjob on the matrix output from (2) specifiying CosineDistance and a cutoff threshold. This should generate a matrix of Rows -> Most similar rows with distances. On Wed, May 13, 2015 at 11:42 PM, Jonathan Seale <jonathanpse...@gmail.com> wrote: > Thanks, Charlie, > > The data has been through lots of processing, but in an attempt to make it > more Mahout-friendly, I've converted it into a single csv table with > columns: star_id, wavelength, intensity. My motivation was to make it like > a user_id, item_id, rating table you might see in other Mahout uses. > > As opposed to using my local machine, I've setup an instance on Amazon with > hopes of turning this into a remote service. So the install is whatever > comes with Amazon's default Mahout installation. > > Jonathan > > > > On Wed, May 13, 2015 at 11:29 PM, Charlie Hack <charles.t.h...@gmail.com> > wrote: > > > Hi Jonathan, how do you have the data stored? More info about your setup > > the better. > > > > > > Charlie > > > > > > > > > > > > > > > > > > > > — > > Sent from Mailbox > > > > > > > > > > On Wednesday, May 13, 2015 at 23:16, Jonathan Seale < > > jonathanpse...@gmail.com>, wrote: > > Scientists, > > > > > > I have an astrophysical application for Mahout that I need help with. > > > > > > I have 1-dimensional stellar spectra for many, many stars. Each spectrum > > > > consists of a series of intensity values, one per wavelength of light. I > > > > need to be able to find the cosine similarity between ALL pairs of stars. > > > > Seems to me this is simply a user-user similarity problem where I have > > > > stars instead of users, wavelengths instead of items, and intensities > > > > instead of ratings/clicks. > > > > > > But I'm having difficulty using mahout's row similarity package (I'm new > to > > > > this, and these days astronomers code pretty exclusively in python). I > know > > > > that I must have to 1) create a sparse matrix where each row is a star, > > > > columns are wavelengths, and the values are intensity, and 2) implement > row > > > > similarity. But I'm just not sure how to do it. Anyone have a good > resource > > > > or be willing to help? I could probably offer some compensation to anyone > > > > that would be willing to provide a little focussed, personalized > > assistance. > > > > > > Thanks, > > > > Jonathan > > >
