Yes. Apache Math linear algebra is very difficult for us to use because their matrices are non-extensible.
But there is actually quite a lot of code to do with random distributions, optimization and quadrature. Those are much more likely to be useful to us. On Mon, Aug 12, 2013 at 3:26 PM, Dmitriy Lyubimov <[email protected]> wrote: > Larger part of mahout-math is linear algebra, which is currently broken for > sparse part of the equation and which we don't use at all. > > One part of the problem is that our use for that library is always a fringe > case, and as far as i can tell, will always continue to be such. > > Another part of the problem is that keeping dependency will invite > bypassing Mahout's solvers and, as a result, architecture inconsistency. > > That said, I guess Ted's argument (which is mainly cost, as i gathered), > trumps the two above. > > > On Mon, Aug 12, 2013 at 3:20 PM, Peng Cheng <[email protected]> wrote: > > > seriously, I would prefer the dependency as a good architectural pattern. > > It encourages other people to use/contribute to it to avoid repetitive > work. > > > > > > On 13-08-12 06:16 PM, Ted Dunning wrote: > > > >> I am fine with it staying. > >> > >> > >> On Mon, Aug 12, 2013 at 3:14 PM, Dmitriy Lyubimov <[email protected]> > >> wrote: > >> > >> So you are ok with apache-math dependency to stay? > >>> > >>> > >>> On Mon, Aug 12, 2013 at 3:09 PM, Ted Dunning <[email protected]> > >>> wrote: > >>> > >>> So I checked on these. The non-trivial issues with replacing Commons > >>>> > >>> Math > >>> > >>>> include: > >>>> > >>>> - Poisson and negative binomial distributions. This would be several > >>>> > >>> hours > >>> > >>>> work to write and test (we have Colt-inherited negative binomial > >>>> distribution, but it takes no longer to write a new one than to test > an > >>>> > >>> old > >>> > >>>> one). > >>>> > >>>> - random number generators. This is about and hour or two of work to > >>>> > >>> pull > >>> > >>>> the MersenneTwister implementation into our code. > >>>> > >>>> - next prime number finder. Not a big deal to replicate, but it would > >>>> > >>> take > >>> > >>>> a few hours to do. > >>>> > >>>> - quadrature. We use an adaptive integration routine to check > >>>> > >>> distribution > >>> > >>>> properties. This, again, would take a few hours to replace. > >>>> > >>>> I really don't see the benefit to this work. > >>>> > >>>> On Mon, Aug 12, 2013 at 2:53 PM, Ted Dunning <[email protected]> > >>>> wrote: > >>>> > >>>> 2 distribution.**PoissonDistribution; > >>>>> 2 distribution.**PascalDistribution; > >>>>> 2 distribution.**NormalDistribution; > >>>>> 1 util.FastMath; > >>>>> 1 random.RandomGenerator; > >>>>> 1 random.MersenneTwister; > >>>>> 1 primes.Primes; > >>>>> 1 linear.RealMatrix; > >>>>> 1 linear.EigenDecomposition; > >>>>> 1 linear.Array2DRowRealMatrix; > >>>>> 1 distribution.RealDistribution; > >>>>> 1 distribution.**IntegerDistribution; > >>>>> 1 analysis.integration.**UnivariateIntegrator; > >>>>> 1 analysis.integration.**RombergIntegrator; > >>>>> 1 analysis.UnivariateFunction; > >>>>> > >>>>> > > > > >
