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Re: The intersection of 2 arrays - where_ar.pro [1/1] [message #8435]

Tue, 04 March 1997 00:00

J.D. Smith
Messages: 214
Registered: August 1996

Senior Member

David P. Steele wrote:
>
> The attached routine (WHERE_ARRAY.PRO) was posted a few years back on this
> newsgroup, courtesy of Stephen Strebel. It uses a vector algorithm, and does
> what I think Phil wants to do.

Just make sure you don't try and use it with big arrays -- it's an n^2 algorithm
(versus the n algorithms posted prior). E.g., to compare two floating 128x128
arrays for overlapping values, the program would create 3 arrays, each of which
takes 1 GB! The routine match() is likely much more efficient for doing
intersections on big arrays. (Unless you have some serious RAM on your machine).

JD

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		Re: The intersection of 2 arrays - where_ar.pro [1/1] By: J.D. Smith on Tue, 04 March 1997 00:00
		Re: The intersection of 2 arrays - where_ar.pro [1/1] By: David.Steele on Tue, 04 March 1997 00:00

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