On Aug 4, 2013 4:32 AM, "Fernando Fernández" <
[email protected]> wrote:
>
> > I thought both methods accept exactly the same drm format so u could
just
> feed the same thing to them?
>
> That's exactly what I'm doing, (or I think I'm doing at least... I will
> look deeply into this in three or four weeks when I get back to work).
>
> As for the movielens example I will try to replicate the tests with
> mahout's ssvd and lanczos and see what happens. I will try also to do the
> opposite and run my actual data in R's prototype with a big enough
machine,
> and run it also with IRLBA package which seems to work pretty well in
terms
> of precision.
>
> Also, maybe it's easy to adapt SSVD prototype in R to use uniform vectors,
> right?
Yes, it is easy, one just needs ot substitute rnorm with runif over -1..1
but it is much more likely that numeric stability issues in prototype power
iterations if any would appear more pronounced because of dense AB'
multiplication as well as qr.
>
> Thanks again,
>
> Fernando.
>
>
> 2013/8/3 Ted Dunning <[email protected]>
>
> > On Sat, Aug 3, 2013 at 3:05 AM, Fernando Fernández <
> > [email protected]> wrote:
> >
> > > > svd.r$d[1:10] [1] 640.63362 244.83635 217.84622 159.15360 158.21191
> > > 145.87261 126.57977 121.90770 106.82918 99.74794[1] "three runs with
> > q=0"
> > > [1] 640.63362 244.83613 217.84493 159.14512 158.20471 145.82572
126.42295
> > > 121.79764 105.99973 98.99649 [1] 640.63362 244.83592 217.84568
159.13914
> > > 158.19299 145.84226 126.46651 121.73629 106.22892 99.11622 [1]
640.63362
> > > 244.83590 217.84482 159.12955 158.19675 145.81728 126.47135 121.79920
> > > 106.45790 99.01242
> > >
> > > [1] "three runs with q=1" [1] 640.63259 244.75889 217.66362 158.40002
> > > 157.61954 145.26448 125.25675 119.74266 104.16382 95.43547 [1]
> > > 640.6327 244.7559 217.6805 158.6019 157.4059 144.9223 124.2859
> > > 119.1194 103.9104 96.6282 [1] 640.63313 244.62599 217.67781 158.72475
> > > 157.13394 145.08462 125.33024 120.20984 102.45867 95.37994
> > >
> > >
> > > I have repeated the runs several times with the same results... Maybe
I'm
> > > still missing something else but given these results I can't apply the
> > rule
> > > of q=1 improves accuracy. At least I have to experiment, my guess is
it
> > do
> > > depends on the dataset. I would like also to repeat this comparison
with
> > > Mahout's SSVD and my dataset and see what happens.
> > >
> > > Dmitriy, thank you very much for your attention and sharing your
thoughts
> > > with me. I really appreciate it.
> > >
> >
> > That is interesting.
> >
> > The results for q=0 and q=1 are remarkably similar which I wouldn't
expect.
> >
