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Re: Reducing an array. [message #32271]

Tue, 01 October 2002 07:25

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

MKatz843@onebox.com (M. Katz) writes:

> In order to perform an OR on 64 bits stored in an array, could you do
> something like this:
>
> a = [0,0,0,1,0,1,0,1,1]
> b = total(a) GT 0
>
> Then, if any of the elements of a are non-zero, b will be TRUE, or 1.
> At least I hope that's what you meant by OR.
>
> Likewise AND would be
>
> c = total(a) EQ n_elements(a)

The original poster was asking for a BITWISE "and" operation, not a
logical "and" operation. He was interested in all the bits of the
result, not just whether any bit was set.

Incidentally, "M"'s formulation is pretty much exactly what I use in
my routine CMAPPLY, which applies selected operations, like AND and
OR, to arrays.

Craig

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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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		Re: Reducing an array. By: Craig Markwardt on Tue, 01 October 2002 07:25
		Re: Reducing an array. By: MKatz843 on Mon, 30 September 2002 23:15
		Re: Reducing an array. By: Craig Markwardt on Mon, 30 September 2002 16:17
		Re: Reducing an array. By: Dick Jackson on Tue, 01 October 2002 13:53

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