comp.lang.idl-pvwave archive: archive » Re: position matching

Home » Public Forums » archive » Re: position matching

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: position matching [message #54008 is a reply to message #54005]

Tue, 15 May 2007 07:14

Paolo Grigis
Messages: 171
Registered: December 2003

Senior Member

Seems to be a recurring theme... here's a nice article:

http://www.dfanning.com/code_tips/slowloops.html

Ciao,
Paolo

cmancone@ufl.edu wrote:
> Hi everyone,
> A common task I have to do is take two lists of stars with x & y
> positions and match up the closest stars within a certain radius (so
> that each star has at most one match, that one being the best match).
> A long time ago I wrote some code to do this that gets the job done,
> but probably not in the fastest way. It just uses a for loop over one
> of the lists and uses a where to search for the closest star to each
> star on the other list. Most of the time this is more than adequate,
> but anytime my star lists get around 10000-20000 stars each (which
> happens on a not-so irregular basis) the program turns into quite a
> beast and takes its sweet time (i.e. a minute or two). Granted, this
> isn't exactly research-stopping time delays, but I'm sure that with a
> well thought-out algorithm, the execution time could be pulled down to
> a handful of seconds. The problem is, I have yet to come up with a
> well thought-out algorithm. I'm sure I'm not the only one who has run
> into this, so I was hoping there might be someone else out there that
> has dealt with the same thing, and knows a better way.
> -Conor
>

Report message to a moderator

[Message index]

		Re: position matching By: cmancone on Tue, 15 May 2007 08:55
		Re: position matching By: Edd Edmondson on Tue, 15 May 2007 08:25
		Re: position matching By: Paolo Grigis on Tue, 15 May 2007 08:14
		Re: position matching By: Edd Edmondson on Tue, 15 May 2007 08:11
		Re: position matching By: cmancone on Tue, 15 May 2007 07:36
		Re: position matching By: Paolo Grigis on Tue, 15 May 2007 07:14
		Re: position matching By: JD Smith on Wed, 16 May 2007 13:47
		Re: position matching By: cmancone on Wed, 16 May 2007 07:09

Previous Topic:	Re: how to write a K with a hat symbol above
Next Topic:	Defining IDL structures given variable type, width and precision

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sat Oct 11 10:26:28 PDT 2025

Total time taken to generate the page: 2.07675 seconds