Ted,
Are you going to commit this?
On Thu, Apr 18, 2013 at 5:18 PM, Ted Dunning <ted.dunn...@gmail.com> wrote:
> Actually, I built a BlockSparseMatrix some time ago that does this.
>
> It was just like our current row sparse matrix except that it allowed for
> blocks instead of rows.
>
> It did assume sparse matrices where the data existed.
>
> Worked a charm on the app in question.
>
> It doesn't appear that I committed it.
>
>
>
>
> On Thu, Apr 18, 2013 at 7:02 AM, Gokhan Capan <gkhn...@gmail.com> wrote:
>
> > Ok, I'll do that.
> >
> > Thank you, Jake.
> >
> >
> > On Thu, Apr 18, 2013 at 4:43 AM, Jake Mannix <jake.man...@gmail.com>
> > wrote:
> >
> > > SparseMatrix is implemented as a Map<Integer, Vector>, you could modify
> > > that class to allow you to chose between dense or sparse rows at
> > > construction time.
> > >
> > >
> > > On Wed, Apr 17, 2013 at 4:01 PM, Robin Anil <robin.a...@gmail.com>
> > wrote:
> > >
> > > > Yes! Yes! Go for it!.
> > > > On Apr 17, 2013 5:52 PM, "Gokhan Capan" <gkhn...@gmail.com> wrote:
> > > >
> > > > > 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
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > >
> > > -jake
> > >
> >
> >
> >
> > --
> > Gokhan
> >
>
--
Gokhan
