comp.lang.idl-pvwave archive: archive » Re: Array Tiling

Home » Public Forums » archive » Re: Array Tiling - The IDL Way

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

Re: Array Tiling - The IDL Way [message #79628 is a reply to message #79574]

Sat, 17 March 2012 09:13

Percy Pugwash
Messages: 12
Registered: January 2012

Junior Member

Thanks for the suggestions.

Unfortunately in this case it seems that the nested for-loop method is actually much faster! I think the reason is that the arrays I'm using are so large (gigabytes in size) that the amount of memory manipulation involved in the TRANSPOSE operation dwarfs the time spend on running a for-loop.

Ah well.

P

On Monday, 12 March 2012 18:54:59 UTC, Mike Galloy wrote:
> On 3/12/12 11:31 AM, Percy Pugwash wrote:
>> I have a large array that I'd like to break up into tiles (square tiles of side T). I would like to have those tiles in the form of a stack, such that my array goes from dimensions [Nx*T,Ny*T] to [T,T,Nx*Ny].
>>
>> Is there any way I can do this using only functions like REFORM and TRANSPOSE and no for-loops? Ideally I'd like to do it in-place too. I've been racking my brain for a nice IDLesque way to do this, but no luck thus far...
>>
>> P
>
> I think this is what you are trying to do:
>
> IDL> a = indgen(10, 10)
> IDL> b = transpose(reform(a, 2, 5, 2, 5), [1, 3, 0, 2])
>
> This will break the image a into 5 tiles of size 2 in each dimension. So
> you can do the following, e.g., to retrieve the tile at (4, 4):
>
> IDL> print, reform(b[4, 4, *, *])
> 88 89
> 98 99
>
> Mike
> --
> Michael Galloy
> www.michaelgalloy.com
> Modern IDL, A Guide to Learning IDL: http://modernidl.idldev.com
> Research Mathematician
> Tech-X Corporation

Report message to a moderator

[Message index]

		Re: Array Tiling - The IDL Way By: rogass on Mon, 12 March 2012 12:32
		Re: Array Tiling - The IDL Way By: rogass on Mon, 12 March 2012 12:28
		Re: Array Tiling - The IDL Way By: Michael Galloy on Mon, 12 March 2012 11:54
		Re: Array Tiling - The IDL Way By: Percy Pugwash on Sat, 17 March 2012 09:13

Previous Topic:	how to extend a vector from size A to size B, (A<B) without "damage" the data in A
Next Topic:	please send your resume

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 15:08:44 PDT 2025

Total time taken to generate the page: 0.47759 seconds