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Re: Assign data point to n-Dimensional grid [message #80597 is a reply to message #80595]

Fri, 22 June 2012 08:14

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article <ada6c25c-b056-4578-8d10-f9fb2fa9694d@googlegroups.com>,
antar3s86@gmail.com wrote:

> Hi
>
> I face a serious problem in the development of my algorithm.In principle it
> is very simple:
>
> I have a data point in a 9-dimensional parameter space (say,
> x1,x2,x3,y1,y2,y3,z1,z2,z3) with x,y,z being physical quantities with
> different units. Furthermore, I have an unequally spaced 9-dimensional
> reference grid and all i have to do is to compute which grid point is closest
> to my data point with respect to all 9 dimensions.
>
> I have to do this several billion times, so I really want to make sure to do
> it as fast as possible.
>
> Any help with that?
>
> cheers

Is your grid separable? That is, does the x-coordinate of
each grid point depend only on x? If it does, you can find
the index of each nearest neighbor independently of the others.

If your grids are regular, you should be able to compute the
nearest neighbor index. Something like this

i = ROUND(nx*(x - xmin)/(xmax - xmin))

If your grids are not regular (not evenly spaced), use
VALUE_LOCATE to do a binary search.

If your grids are not separable, you have a much more difficult
problem.

Ken Bowman

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[Message index]

		Re: Assign data point to n-Dimensional grid By: Kenneth P. Bowman on Fri, 22 June 2012 11:28
		Re: Assign data point to n-Dimensional grid By: Craig Markwardt on Fri, 22 June 2012 10:49
		Re: Assign data point to n-Dimensional grid By: antar3s86 on Fri, 22 June 2012 09:06
		Re: Assign data point to n-Dimensional grid By: antar3s86 on Fri, 22 June 2012 08:38
		Re: Assign data point to n-Dimensional grid By: Kenneth P. Bowman on Fri, 22 June 2012 08:14

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