Hi Deb, On Tue, Feb 25, 2014 at 7:07 AM, Debasish Das <debasish.da...@gmail.com> wrote: > Continuation on last email sent by mistake: > > Is cpl license is compatible with apache ? > > http://opensource.org/licenses/cpl1.0.php
Based on what I read here, there is no problem to include CPL code in apache project as long as the code isn't modified, and we include the maven binary. https://www.apache.org/legal/3party.html > Mallet jars are available on maven. They have hessian based solvers which > looked interesting along with bfgs and cg. We found that hessian based solvers don't scale as the # of features grow, and we have lots of customers trying to train sparse input. That's our motivation to work on L-BFGS which approximate hessian using just a few vectors. Just take a look at MALLET, and it does have L-BFGS and its variant OWL-QN which can tackle L1 problem. Since implementing L-BFGS is very subtle, I don't know the quality of the mallet implementation. Personally, I implemented one based on textbook, and not very stable. If MALLET is robust, I'll go for it since it has more features, and already in maven. > Note that right now the version is not blas optimized. With jblas or > netlib-java discussions that's going on it can be improved. Also it runs on > a single thread which can be improved...so there is scope for further > improvements in the code. I think it will not impact performance even it's not blas optimized nor multi-threaded, since most of the parallelization is in computing gradientSum and lossSum in Spark, and the optimizer just takes gradientSum, lossSum, and weights to get the newWeights. As a result, 99.9% of time is in computing gradientSum and lossSum. Only small amount of time is in optimization. > > Basically Xiangrui, is there a push back on making optimizers part of spark > mllib ? I am exploring cg and qp solvers for spark mllib as well and I am > developing these as part of mllib optimization. I was hoping we should be > able to publish mllib as a maven artifact later. > > Thanks. > Deb Thanks. Sincerely, DB Tsai Machine Learning Engineer Alpine Data Labs -------------------------------------- Web: http://alpinenow.com/
