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fast search [message #50819]

Tue, 17 October 2006 05:09

m.goullant@gmail.com is currently offline

m.goullant@gmail.com
Messages: 10
Registered: July 2006

Junior Member

Hi there,

I have the following problem:

;data structure of an irregular point cloud
x = points.x
y = points.y
z = points.z

search radio
radio = 8

FOR i=0L,N_ELEMENTS(z)-1 DO BEGIN

square = WHERE(x LE x[i] + radio AND x GE x[i] - radio AND y LE
y[i] + radio AND y GE y[i] - radio)
;(...)

ENDFOR

I realize that WHERE will do the job, but at very low efficiency.
WHERE
makes no assumptions about the list being ordered. It seems to me it
has
to check every element of the array, requiring N steps for an N-element
array

There is a faster way to do this?

thanks,
Marie

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[Message index]

		fast search By: m.goullant@gmail.com on Tue, 17 October 2006 05:09
		Re: fast search By: greg michael on Sat, 21 October 2006 14:42
		Re: fast search By: m.goullant@gmail.com on Fri, 20 October 2006 17:37
		Re: fast search By: greg michael on Thu, 19 October 2006 07:24
		Re: fast search By: greg michael on Thu, 19 October 2006 07:18
		Re: fast search By: m.goullant@gmail.com on Thu, 19 October 2006 03:51

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