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Re: row calculation in a 2D array [message #12587]

Wed, 26 August 1998 00:00

Alex Schuster
Messages: 124
Registered: February 1997

Senior Member

Jonas wrote:

> This was kind of a special example since total could do all the work. What
> if I would like to do another calculation where total is not applicable...
> in other words:
> is there generally an easy way to perform the same calculation over all the
> (sub-)rows in a in a 2D array?

Calculating the average of each row could be done by matrix
multiplication:

a = findgen( 10, 10 )
b = reform( fltarr( 10 ) + 1, 1, 10 )
average = reform( b # a / 10 )
print, average

4.50000 14.5000 24.5000 34.5000 44.5000
54.5000
64.5000 74.5000 84.5000 94.5000

Other things would be more difficult, though, and sometimes you just
cannot avoid loops.

Alex
--
Alex Schuster Wonko@weird.cologne.de PGP Key available
alex@pet.mpin-koeln.mpg.de

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[Message index]

		Re: row calculation in a 2D array By: Alex Schuster on Wed, 26 August 1998 00:00
		Re: row calculation in a 2D array By: Jonas on Wed, 26 August 1998 00:00
		Re: row calculation in a 2D array By: Martin Schultz on Tue, 25 August 1998 00:00
		Re: row calculation in a 2D array By: Jonas on Tue, 25 August 1998 00:00
		Re: row calculation in a 2D array By: Kevin Ivory on Tue, 25 August 1998 00:00
		Re: row calculation in a 2D array By: David Kastrup on Tue, 25 August 1998 00:00

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