comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Re: Matching 2 lists

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

Re: Matching 2 lists [message #72218 is a reply to message #72217]

Sat, 21 August 2010 10:03

David Baker
Messages: 6
Registered: August 2010

Junior Member

On Aug 21, 5:52 pm, Paulo Penteado <pp.pente...@gmail.com> wrote:
> On Aug 21, 1:37 pm, David Baker <de...@le.ac.uk> wrote:
>
>>>> If you're using IDL 8.0, you could modify match_2d to return a list of
>>>> length n_a, where each element is an array of indices into b.
>
>>> Thanks for the advice, whilst I maybe comfortable programming basic
>>> stuff I can't even begin to follow the match_2d code so wouldn't know
>>> where exactly to code in what you suggest. But that is exactly what
>>> I'm after.
>
>>> -Cheers,
>>> David
>
>> You mentioned using IDL 8.0. My university is currently still on
>> 7.1.1, is there anything unique about IDL 8.0 to the solution you
>> propose?
>
> Lists and empty arrays. In that case, because each element of A can
> have a different number of matches, so each element of the list is an
> array of a different size (possibly empty, if there are no matches).
>
> The most direct way to do something similar in IDL 7 is a pointer
> array, where each element points to the array of indices that match
> the corresponding element of A. Which is more awkward to use due to
> the need to dereference the pointer, and the need to test (with null
> pointers, for instance) for the no-match case.

OK, but it should still be possible? You're suggesting something like
a two element structure, one element contains the index from A the
other element contains a pointer listing the indicies of any object
from list B that is within the search radius? The structure would just
need to grow via a=[b,c] for each object in A that has matches to
those in B (though this would obviously cause a speed penalty I think
it might outweigh that caused by looping over my lists). The tricky
part I guess (at least for me) is finding out where match_2d prints
out the indicies from B that match to each individual index in A.

-David

Report message to a moderator

[Message index]

		Re: Matching 2 lists By: David Baker on Sun, 22 August 2010 00:06
		Re: Matching 2 lists By: Jeremy Bailin on Sat, 21 August 2010 12:48
		Re: Matching 2 lists By: David Baker on Sat, 21 August 2010 10:03
		Re: Matching 2 lists By: penteado on Sat, 21 August 2010 09:52
		Re: Matching 2 lists By: David Baker on Sat, 21 August 2010 09:37
		Re: Matching 2 lists By: David Baker on Sat, 21 August 2010 08:35
		Re: Matching 2 lists By: Gray on Sat, 21 August 2010 08:28
		Re: Matching 2 lists By: David Baker on Sat, 21 August 2010 08:16
		Re: Matching 2 lists By: Jeremy Bailin on Thu, 26 August 2010 07:10

Previous Topic:	Re: mode of a continuous distribution
Next Topic:	Re: web apps and idl

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 19:58:02 PDT 2025

Total time taken to generate the page: 0.00614 seconds