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Avoiding FOR loops (version googleplex.infinity) [message #59696]

Mon, 07 April 2008 05:42

Gaurav
Messages: 50
Registered: January 2007

Member

Dear all,

I know IDL provides us with neat tricks to avoid the processor monster
called FOR loop but I always tend to become incapable using the magic
tricks viz WHERE when I need them the most. Will someone please show
me the way here.

What I have is a 2D Byte array. For each element I need to find the
number of elements in a surrounding 5 X 5 window that is equal to the
element under scrutiny. It is easy to achieve this using FOR loops and
EXTRAC & WHERE functions, but it obviously becomes very slow for large
arrays.

How do I avoid the FOR loop in this case using wildcards and the ":"
operator?

Like always, I hope I do not get to gnaw at my fingernails for long.

Cheers
Gaurav

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[Message index]

		Avoiding FOR loops (version googleplex.infinity) By: Gaurav on Mon, 07 April 2008 05:42
		Re: Avoiding FOR loops (version googleplex.infinity) By: MichaelT on Wed, 09 April 2008 05:56
		Re: Avoiding FOR loops (version googleplex.infinity) By: Gaurav on Wed, 09 April 2008 05:33
		Re: Avoiding FOR loops (version googleplex.infinity) By: David Fanning on Fri, 11 April 2008 05:56
		Re: Avoiding FOR loops (version googleplex.infinity) By: R.G. Stockwell on Fri, 11 April 2008 09:15
		Re: Avoiding FOR loops (version googleplex.infinity) By: Gaurav on Fri, 11 April 2008 05:41
		Re: Avoiding FOR loops (version googleplex.infinity) By: weitkamp on Fri, 11 April 2008 00:52
		Re: Avoiding FOR loops (version googleplex.infinity) By: Gaurav on Thu, 10 April 2008 23:15
		Re: Avoiding FOR loops (version googleplex.infinity) By: Tom McGlynn on Fri, 11 April 2008 08:04
		Re: Avoiding FOR loops (version googleplex.infinity) By: Tom McGlynn on Thu, 10 April 2008 11:49
		Re: Avoiding FOR loops (version googleplex.infinity) By: Gaurav on Mon, 14 April 2008 22:46
		Re: Avoiding FOR loops (version googleplex.infinity) By: David Fanning on Fri, 11 April 2008 10:38
		Re: Avoiding FOR loops (version googleplex.infinity) By: Greg Hennessy on Fri, 11 April 2008 10:32
		Re: Avoiding FOR loops (version googleplex.infinity) By: David Fanning on Fri, 11 April 2008 09:44

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