comp.lang.idl-pvwave archive: archive » [Q]: ID analog to FORTRAN "sign" function

Home » Public Forums » archive » [Q]: ID analog to FORTRAN "sign" function

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: [Q]: ID analog to FORTRAN "sign" function [message #21992 is a reply to message #21932]

Thu, 12 October 2000 00:00

Phillip David
Messages: 36
Registered: April 1999

Member

Dick Jackson wrote:
>
> Do I dare offer one more? Subscript lookups seem faster than arithmetic
> operations, making this one faster, more compact and no less cryptic! :-)
>
> Return, Abs(a) * ([-1, 1])[b GE 0]

to which I reply:

If this one really works, then why not go even one step further?

Return, ([-Abs(a), Abs(a)])[b GE 0]

or

Return, ([a, -a])[(a*b) LT 0]

I haven't timed either of these to find out if they're truly better (as
I don't have IDL on my newsgroup computer), but they MIGHT work
better...

Phillip

Report message to a moderator

[Message index]

		[Q]: ID analog to FORTRAN "sign" function By: Rostyslav Pavlichenko on Fri, 06 October 2000 22:34
		Re: [Q]: ID analog to FORTRAN "sign" function By: Mark Hadfield on Thu, 12 October 2000 13:50
		Re: [Q]: ID analog to FORTRAN "sign" function By: Phillip David on Thu, 12 October 2000 00:00
		Re: [Q]: ID analog to FORTRAN "sign" function By: Dick Jackson on Thu, 12 October 2000 00:00
		Re: [Q]: ID analog to FORTRAN "sign" function By: Mark Hadfield on Mon, 09 October 2000 14:45
		Re: [Q]: ID analog to FORTRAN "sign" function By: Dick Jackson on Fri, 13 October 2000 00:00

Previous Topic:	3D Visualization
Next Topic:	Re: BINARY FILES

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 22:18:07 PDT 2025

Total time taken to generate the page: 1.03825 seconds