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Re: [Q]: ID analog to FORTRAN "sign" function [message #22023 is a reply to message #21932]

Mon, 09 October 2000 14:45

Mark Hadfield
Messages: 783
Registered: May 1995

Senior Member

"Alex Schuster" <alex@pet.mpin-koeln.mpg.de> wrote in message
news:39E1C067.16F7488E@pet.mpin-koeln.mpg.de...
> Rostyslav Pavlichenko wrote:
>
>> Does the IDl have something close to Fortran SIGN (DSIGN... so on...)
>> functions
>> ...
>> result = SIGN (a, b)
>> a (Input) Must be of type integer or real.
>>
>> b Must have the same type and kind parameters as a.
>>
>> Results:
>> =========
>> The result type is the same as a.
>> The value of the result is
>> | a | if b >= zero
>> and -| a | if b < zero.
>> ...
> No, but you can easily write it:
>
> function sign, a, b
> if ( b ge 0 ) then $
> return, abs( a ) $
> else $
> return, -abs( a )
> end

The following is more compact and works when b is an array

return, abs(a) * (fix(b ge 0) - fix(b lt 0))

---
Mark Hadfield
m.hadfield@niwa.cri.nz http://katipo.niwa.cri.nz/~hadfield/
National Institute for Water and Atmospheric Research
PO Box 14-901, Wellington, New Zealand

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[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

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