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From: | Werner Van Belle | Date: | March 30 2010 10:31am |

Subject: | Re: How to deal with 96 Dimensional Points ? | ||

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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 ? > > Does anybody have an idea about this ? > > Wkr, > > -- > http://werner.yellowcouch.org/ > > > > > > -- > Bier met grenadyn > 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/ Attachment: [application/pgp-signature] OpenPGP digital signature signature.asc

Thread | ||
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• How to deal with 96 Dimensional Points ? | Werner Van Belle | 30 Mar |

• Re: How to deal with 96 Dimensional Points ? | Chris W | 30 Mar |

• Re: How to deal with 96 Dimensional Points ? | Geert-Jan Brits | 31 Mar |

• Re: How to deal with 96 Dimensional Points ? | Werner Van Belle | 31 Mar |

• Re: How to deal with 96 Dimensional Points ? | Werner Van Belle | 31 Mar |

• Re: How to deal with 96 Dimensional Points ? | Chris W | 31 Mar |

• Re: How to deal with 96 Dimensional Points ? | Werner Van Belle | 30 Mar |

• Re: How to deal with 96 Dimensional Points ? | Werner Van Belle | 30 Mar |