Re: [R] Random projection

2018-12-05 Thread Jan Galkowski
Ms Fleming,

This blog post (of mine) may be of interest and hopefully of help:

https://667-per-cm.net/2018/11/20/the-johnson-lindenstrauss-lemma-and-the-paradoxical-power-of-random-linear-operators-part-1/
Cheers!

--
Jan Galkowski (o°)
Westwood, MA

(pronouns: *he, him, his*)

*Keep your energy local*.  --John Farrell, *ILSR[1]*



Links:

  1. http://ilsr.org

[[alternative HTML version deleted]]

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Re: [R] Random projection

2018-12-04 Thread Jeff Newmiller
Your multiplication description sounds more like matrix multiplication than 
scalar multiplication. R supports matrix multiplication with the %*% operator.

I didn't follow the rest of your description... are you doing a homework 
assignment? There is a no homework policy on this list...

On December 4, 2018 2:06:43 PM PST, rosie fleming  
wrote:
>Hello I was wondering if anyone could help. I am using R to perform
>random projection on Gaussians. 
>I need to take k Gaussian random vectors U1,...,Uk in R(reals) 
>Then for any vector v in d dimensions, perform the random projection: 
>f(v) = v.U1, v.U2, ..., v.Uk which reduces v from d dimensions to k
>dimensions 
>So i need v1,...vn so n vectors 
>
>and then the basic idea is that the relative orders will be preserved
>between the vectors v after projection ie the nearet neighbours for
>each vectors will be the same before projection (v1,v2,...,vn) and
>after projection f(v1),...f(vk) 
>
>I'm struggling to produce this in R. I've managed to make a matrix for
>U and V 
>However I now need to use the scalar product to perform the projection,
>taking each row of v (vi) and multiplying it with every column of the U
>matrix. I need to perform this for n vectors and have a matrix as the
>outcome. 
>
>This would then allow me to find the distances between each f(vi)! 
>
>Any help would be greatly appreciated, thankyou!
>__
>R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

-- 
Sent from my phone. Please excuse my brevity.

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[R] Random projection

2018-12-04 Thread rosie fleming
Hello I was wondering if anyone could help. I am using R to perform random 
projection on Gaussians. 
I need to take k Gaussian random vectors U1,...,Uk in R(reals) 
Then for any vector v in d dimensions, perform the random projection: 
f(v) = v.U1, v.U2, ..., v.Uk which reduces v from d dimensions to k dimensions 
So i need v1,...vn so n vectors 

and then the basic idea is that the relative orders will be preserved between 
the vectors v after projection ie the nearet neighbours for each vectors will 
be the same before projection (v1,v2,...,vn) and after projection 
f(v1),...f(vk) 

I'm struggling to produce this in R. I've managed to make a matrix for U and V 
However I now need to use the scalar product to perform the projection, taking 
each row of v (vi) and multiplying it with every column of the U matrix. I need 
to perform this for n vectors and have a matrix as the outcome. 

This would then allow me to find the distances between each f(vi)! 

Any help would be greatly appreciated, thankyou!
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Re: [R] Random Projection

2013-10-04 Thread Stefan Evert

On 3 Oct 2013, at 22:39, Monaghan, David dmonag...@gc.cuny.edu wrote:

 I was wondering, has anyone has encountered an R package that performs random 
 projection/random mapping?  RP is a procedure that is akin to Principal 
 Components Analysis in that it accomplishes dimensionality reduction, but is 
 far more computationally efficient.  I have been searching for some time, but 
 haven't seen anything on CRAN-r yet.  

The experimental wordspace package available from R-Forge has an 
implementation of RI in the dsm.projection() function.  See

https://r-forge.r-project.org/R/?group_id=783

for download / installation.

Best,
Stefan



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[R] Random Projection

2013-10-03 Thread Monaghan, David
Hello:

I was wondering, has anyone has encountered an R package that performs random 
projection/random mapping?  RP is a procedure that is akin to Principal 
Components Analysis in that it accomplishes dimensionality reduction, but is 
far more computationally efficient.  I have been searching for some time, but 
haven't seen anything on CRAN-r yet.  


David Monaghan
Sociology Ph.D. Candidate, CUNY Graduate Center
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