Thank you, Jake. I suspected as much about Colt. On Jun 18, 2013 8:30 PM, "Jake Mannix" <jake.man...@gmail.com> wrote:
> On Tue, Jun 18, 2013 at 6:14 PM, Dmitriy Lyubimov <dlie...@gmail.com> > wrote: > > > Hello, > > > > so i finally got around to actually do it. > > > > I want to get Mahout sparse vectors and matrices (DRMs) and rebuild some > > solvers using spark and Bagel /scala. > > > > I also want to use in-core solvers that run directly on Mahout. > > > > Question #1: which mahout artifacts are better be imported if I don't > want > > to pick the hadoop stuff dependencies? Is there even such a separation of > > code? I know mahout-math seems to try to avoid being hadoop specfic but > not > > sure if it is followed strictly. > > > > mahout-math should not depend on hadoop apis at all, if you build it and > hadoop gets pulled in via maven, then file a ticket, that's a bug. > > > > Question #2: which in-core solvers are available for Mahout matrices? I > > know there's SSVD, probably Cholesky, is there something else? In > > paticular, i need to be solving linear systems, I guess Cholesky should > be > > equipped enough to do just that? > > > > Question #3: why did we try to import Colt solvers rather than actually > > depend on Colt in the first place? Why did we not accept Colt's sparse > > matrices and created native ones instead? > > > > Colt seems to have a notion of parse in-core matrices too and seems like > a > > well-rounded solution. However, it doesn't seem like being actively > > supported, whereas I know Mahout experienced continued enhancements to > the > > in-core matrix support. > > > > Colt was totally abandoned, and I talked to the original author and he > blessed > it's adoption. When we pulled it in, we found it was woefully undertested, > and > tried our best to hook it in with proper tests and use APIs that fit with > the use > cases we had. Plus, we already had the start of some linear apis (i.e. > the Vector interface) and dropping the API completely seemed not terribly > worth it at the time. > > > > > > Thanks in advance > > -Dmitriy > > > > > > -- > > -jake >