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
