List: General Discussion « Previous MessageNext Message » From: Werner Van Belle Date: March 30 2010 10:31am Subject: Re: How to deal with 96 Dimensional Points ? View as plain text
```Johan De Meersman wrote:
> Well... a "point" in an n-dimensional space, is a location that has a
> defined value for each of it's n dimensions. If you have a value for
> each of your 96 dimensions, you have a point.
Well, it's fairly simple. If you have two points with 96 values in each.
Point1=(x1,...x96) and Point2=(y1,...,y96). The distance between these
two is

d=sqrt( (x_1-y_1)^2 + ... + (x_96-y_96)^2 )

There is no magic in this.
> The mathematics of comparing distances in 96 dimensions is beyond me,
> though :-) I guess a good start would be looking at comparing
> distances in 2 and 3 dimensions (vector math, that is) and trying to
> extrapolate a method from that. Alternatively, hire a mathematician :-p
Extrapolating from lower dimensions doesn't work too well. In this case
this would mean storing 48 different points and then trying to define a
distance measure based on each individual point. I'm not sure this is
feasable.

In general: KD-trees are quite good tools to deal with such large
dimensional spaces, but I see no possibility to use them in mysql,

Wkr,

>
>
> On Tue, Mar 30, 2010 at 11:39 AM, Werner Van Belle
> <werner@stripped <mailto:werner@stripped>> wrote:
>
>     Hello,
>
>     I have been pondering this for a while, but never really looked deeply
>     into the problem.
>
>     I have 96 dimensional points and I would like to pose queries such as:
>     'give me all points that are within such a radius of this one'.
>     The gis
>     extensions to mysql might support such type of query. The problem
>     is of
>     course that points are 2 dimensional and I'm not sure whether I can
>     extend it to more than 3 dimensions ?
>
>
>     Wkr,
>
>     --
>     http://werner.yellowcouch.org/
>
>
>
>
>
> --
> Is als mosterd by den wyn
> Sy die't drinkt, is eene kwezel
> Hy die't drinkt, is ras een ezel

--
http://werner.yellowcouch.org/

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How to deal with 96 Dimensional Points ?Werner Van Belle30 Mar
• Re: How to deal with 96 Dimensional Points ?Chris W30 Mar
• Re: How to deal with 96 Dimensional Points ?Geert-Jan Brits31 Mar
• Re: How to deal with 96 Dimensional Points ?Werner Van Belle31 Mar
• Re: How to deal with 96 Dimensional Points ?Werner Van Belle31 Mar
• Re: How to deal with 96 Dimensional Points ?Chris W31 Mar
Re: How to deal with 96 Dimensional Points ?Werner Van Belle30 Mar
Re: How to deal with 96 Dimensional Points ?Werner Van Belle30 Mar