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Re: How to rebin complex array? [message #39019 is a reply to message #39016]

Wed, 14 April 2004 00:39

Timm Weitkamp
Messages: 66
Registered: August 2002

Member

On 13.04.04 at 15:57 -0700, Yunxiang Zhang wrote:

> I wanna do the following thing as fast as possible.
>
> ;creat a complex array
> a=complexarr(na)
> ;replicate the array k times
> b=rebin(a,na,k)
>
> But rebin won't accept complex array. :( What should I do?

This here is probably what you want:

a=complexarr(na) ; create a complex array
u = 1 + FLTARR(k) ; create unit vector with k elements
b = a # u ; matrix multiplication of a and u

By the way, there is a good reason for REBIN not to work on complex
arrays, and that is the fact that there is not really any proper way of
interpolating between two complex values. (You could argue that
next-neighbor sampling should still be possible.)

> Another similiar question is what is the best solution to replicate a 2d
> image eg dist(512,512) k times to get a k-frame "still movie" as a 3d array
> movie(512,512,k) without using any loops?

As previous posters have said, there's no reason why REBIN shouldn't work
here, given that DIST yields a real-valued result. But *if* you did have a
complex array that you wanted to replicate in the manner described above,
or if you want to avoid REBIN for some other reason, and not use loops,
then I'd probably do this:

s = SIZE(image)
movie = MAKE_ARRAY(s[1], s[2], TYPE=s[3])
movie[*] = image[*] # (1.0 + FLTARR(k))

Cheers,

Timm

--
Timm Weitkamp <http://people.web.psi.ch/weitkamp>

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[Message index]

		Re: How to rebin complex array? By: Yunxiang Zhang on Wed, 14 April 2004 13:01
		Re: How to rebin complex array? By: R.G. Stockwell on Wed, 14 April 2004 09:31
		Re: How to rebin complex array? By: James Kuyper on Wed, 14 April 2004 06:47
		Re: How to rebin complex array? By: Timm Weitkamp on Wed, 14 April 2004 00:39
		Re: How to rebin complex array? By: Peter Mason on Tue, 13 April 2004 17:47
		Re: How to rebin complex array? By: Mark Hadfield on Tue, 13 April 2004 17:10

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