Yes, it should be. I thought Ted implied VectorWritable does it only this
way and non other.

If we can differentiate I'd rather do it. Implying that if you save in one
format (non-sequential) we'd support it with caveat that it's subpar in
certain cases whereas where you want to format input sequentially, we'd
eliminate vector prebuffering stage. Yes, that will work. Thank you, Jake.

-d


On Mon, Dec 13, 2010 at 4:26 PM, Jake Mannix <[email protected]> wrote:

> Dmitriy,
>
>  You should be able to specify that your matrices be stored in
> SequentialAccessSparseVector format if you need to.  This is
> almost always the right thing for HDFS-backed matrices, because
> HDFS is write-once, and SASVectors are optimized for read-only
> sequential access, which is your exact use case, right?
>
>  -jake
>
> On Mon, Dec 13, 2010 at 4:21 PM, Dmitriy Lyubimov <[email protected]>
> wrote:
>
> > I don't think sequentiality is a requirement in the case i am working on.
> > However, let me peek at the code first. I am guessing it is some form of
> a
> > near-perfect hash, in which case it may not be possible to read it in
> parts
> > at all. Which would be bad, indeed. I would need to find a completely
> > alternative input format then to overcome my case.
> >
> > On Mon, Dec 13, 2010 at 4:01 PM, Ted Dunning <[email protected]>
> > wrote:
> >
> > > I don't thikn that sequentiality part of the contract.
> > >  RandomAccessSparseVectors are likely to
> > > produce disordered values when serialized, I think.
> > >
> > > On Mon, Dec 13, 2010 at 1:48 PM, Dmitriy Lyubimov <[email protected]>
> > > wrote:
> > >
> > > > I will have to look at details of VectorWritable to make sure all
> cases
> > > are
> > > > covered (I only took a very brief look so far). But as long as it is
> > able
> > > > to
> > > > produce elements in order of index increase, push technique will
> > > certainly
> > > > work for most algorithms (and in some cases, notably with SSVD, even
> if
> > > it
> > > > produces the data in non-sequential way, it would work too ) .
> > > >
> > >
> >
>

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