Ok i can re-do this to use murmur then.
"unit Guassian vectors" is what the original paper("funding structure
with randomness... ") refers to as the first suggested way of
generating Omega.
As you said, i tried to find the exact meaning of this but till this
day am a little bit fuzzy about what they meant there.
I have always suspected that norm distribution should be o.k. too
On Wed, Apr 6, 2011 at 1:44 PM, Ted Dunning <[email protected]> wrote:
> Interesting point. If you don't need to re-use the vector ever, then there
> is no need to generate it coherently.
> Unit Gaussian vector is an ambiguous term just the way you say, btw. For
> random projections using a vector
> composed of random elements each independently drawn from a unit normal
> distribution should be fine. The
> result will be approximately orthogonal and if you divide by the number of
> elements, approximately orthornormal.
> That is all that is required for the random projection work.
>
> On Wed, Apr 6, 2011 at 1:33 PM, Dmitriy Lyubimov <[email protected]> wrote:
>>
>> Actually I ended up not to use even that i have an implementation. I
>> am currently using just Random.nextGaussian since i needed to generate
>> single Gaussian vectors and I meant to ask if that's the best way to
>> do it.
>>
>> I had a version once that used conversion from uniformly generated
>> murmur hash to gaussian similarly to what you discussed but again, I
>> had doubts that's the way. What's the way?
>>
>> -D
>>
>> On Wed, Apr 6, 2011 at 1:02 AM, Ted Dunning <[email protected]> wrote:
>> > The random matrix that dmitriy has uses MurmurHash based on the two
>> > indices
>> > to create the random values. They aren't cached since they are
>> > generated
>> > fairly quickly.
>> >
>> > On Wed, Apr 6, 2011 at 12:36 AM, Sean Owen (JIRA) <[email protected]>
>> > wrote:
>> >
>> >>
>> >> [
>> >>
>> >> https://issues.apache.org/jira/browse/MAHOUT-550?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016285#comment-13016285]
>> >>
>> >> Sean Owen commented on MAHOUT-550:
>> >> ----------------------------------
>> >>
>> >> Well it turns out MersenneTwisterRNG won't take a new seed, but it just
>> >> means setSeed() in RandomWrapper needs to make a new RNG instead. I can
>> >> add
>> >> that, it's a detail.
>> >>
>> >> > Add RandomVector and RandomMatrix
>> >> > ---------------------------------
>> >> >
>> >> > Key: MAHOUT-550
>> >> > URL: https://issues.apache.org/jira/browse/MAHOUT-550
>> >> > Project: Mahout
>> >> > Issue Type: New Feature
>> >> > Components: Math
>> >> > Reporter: Lance Norskog
>> >> > Assignee: Sean Owen
>> >> > Attachments: MAHOUT-550.patch, MAHOUT-550.patch,
>> >> RandomMatrix.patch
>> >> >
>> >> >
>> >> > Add Vector and Matrix implementations that generate a unique and
>> >> reproducible random number for each index.
>> >>
>> >> --
>> >> This message is automatically generated by JIRA.
>> >> For more information on JIRA, see:
>> >> http://www.atlassian.com/software/jira
>> >>
>> >
>
>
