I didn't quite get that, and assuming you tell me to implement it
Thanks
On Thu, Apr 18, 2013 at 1:44 AM, Robin Anil <robin.a...@gmail.com> wrote:
> Make one?
> On Apr 17, 2013 5:37 PM, "Gokhan Capan" <gkhn...@gmail.com> wrote:
>
> > Robin,
> >
> > Aren't SparseRowMatrix rows are sparse vectors? In my use case row
> vectors
> > don't need to be sparse, they are either full or empty.
> >
> >
> > On Thu, Apr 18, 2013 at 1:32 AM, Robin Anil <robin.a...@gmail.com>
> wrote:
> >
> > > SparseRowMatrix?
> > > On Apr 17, 2013 5:26 PM, "Gokhan Capan" <gkhn...@gmail.com> wrote:
> > >
> > > > Hi,
> > > >
> > > > Using Mahout Matrix interface I want to represent some data where the
> > row
> > > > vector is dense iff an instance is associated to this row index,
> empty
> > > > otherwise. The max possible index for rows (a.k.a. rowSize) is
> defined.
> > > >
> > > > I never query the matrix by column.
> > > > I want to be able to add rows if the rowId is not larger than the
> > > rowSize.
> > > >
> > > > Does a matrix implementation exist that I can use, or should I write
> > one?
> > > >
> > > > Not to cause an XY problem, here is the particular use case:
> > > > I row-index a latent factor matrix (for recommendation) with userIDs
> > (and
> > > > itemIDs for the other matrix). I need fast access to a row vector (to
> > > > estimate a score for a user-item pair)
> > > >
> > > > I tried a SparseColumnMatrix, which degrades -it is designed for fast
> > > > access by column- the performance. I may use a DenseMatrix, which
> would
> > > > either bring a memory overhead (by allocating row vectors for empty
> > > rows),
> > > > or result in losing the ability to add new rows (if I map the userIds
> > to
> > > > {1,2,...,noOfCurrentUsers} space)
> > > >
> > > > Thanks
> > > >
> > > > --
> > > > Gokhan
> > > >
> > >
> >
> >
> >
> > --
> > Gokhan
> >
>
--
Gokhan
