SequentialBigSvd Power Iterations

[Ahmed Elgohary <aa...@gmail.com>]

Hi,
I am trying to use SequentialBigSvd as an in-memory implementation for the
ssvd. But, It is not clear to me if there is a reason behind not supporting
power iterations (i.e. power iterations Q is always set to zero) in the
current implementation. Are power iterations not needed in small scale
settings?

thanks,

--ahmed

Re: SequentialBigSvd Power Iterations

[Ted Dunning <te...@gmail.com>]

The reason it doesn't do the iterations is that I didn't realize how
important they were at the time I wrote the sequential implementations.

I wrote the implementations largely as practice attempts before talking too
much about the map-reduce implementation.  Dmitriy was primary on the
map-reduce implementation and added some significant capabilities like the
power iteration and PCA options.

It would be excellent to back-port those capabilities to the sequential
versions.

D's upcoming scala implementations should be interesting as well.



On Fri, Aug 2, 2013 at 10:49 AM, Dmitriy Lyubimov <dl...@gmail.com> wrote:

> it would seem it just was not implemented.
>
> It is pretty easy though. I have in-core implementation ported to scala dsl
> [1] which will find its way into Mahout -0.9 as a part of MAHOUT-1297 if i
> am successful in convincing PMC it is of use to community.
>
>
> On Fri, Aug 2, 2013 at 9:32 AM, Ahmed Elgohary <aa...@gmail.com> wrote:
>
> > Hi,
> > I am trying to use SequentialBigSvd as an in-memory implementation for
> the
> > ssvd. But, It is not clear to me if there is a reason behind not
> supporting
> > power iterations (i.e. power iterations Q is always set to zero) in the
> > current implementation. Are power iterations not needed in small scale
> > settings?
> >
> > thanks,
> >
> > --ahmed
> >
>

Re: SequentialBigSvd Power Iterations

[Dmitriy Lyubimov <dl...@gmail.com>]

[1]
http://weatheringthrutechdays.blogspot.com/2013/07/scala-dsl-for-mahout-in-core-linear.html


On Fri, Aug 2, 2013 at 10:49 AM, Dmitriy Lyubimov <dl...@gmail.com> wrote:

> it would seem it just was not implemented.
>
> It is pretty easy though. I have in-core implementation ported to scala
> dsl [1] which will find its way into Mahout -0.9 as a part of MAHOUT-1297
> if i am successful in convincing PMC it is of use to community.
>
>
> On Fri, Aug 2, 2013 at 9:32 AM, Ahmed Elgohary <aa...@gmail.com> wrote:
>
>> Hi,
>> I am trying to use SequentialBigSvd as an in-memory implementation for the
>> ssvd. But, It is not clear to me if there is a reason behind not
>> supporting
>> power iterations (i.e. power iterations Q is always set to zero) in the
>> current implementation. Are power iterations not needed in small scale
>> settings?
>>
>> thanks,
>>
>> --ahmed
>>
>
>

Re: SequentialBigSvd Power Iterations

[Dmitriy Lyubimov <dl...@gmail.com>]

it would seem it just was not implemented.

It is pretty easy though. I have in-core implementation ported to scala dsl
[1] which will find its way into Mahout -0.9 as a part of MAHOUT-1297 if i
am successful in convincing PMC it is of use to community.


On Fri, Aug 2, 2013 at 9:32 AM, Ahmed Elgohary <aa...@gmail.com> wrote:

> Hi,
> I am trying to use SequentialBigSvd as an in-memory implementation for the
> ssvd. But, It is not clear to me if there is a reason behind not supporting
> power iterations (i.e. power iterations Q is always set to zero) in the
> current implementation. Are power iterations not needed in small scale
> settings?
>
> thanks,
>
> --ahmed
>