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Re: fractional powers of negative numbers? [message #8810 is a reply to message #8809]

Mon, 28 April 1997 00:00

Jack Saba
Messages: 30
Registered: January 1996

Member

IDL is computing -(5.^1.51) in your example. If you try (-5.)^1.51, you
will get an error.

Med Bennett wrote:
>
> Can someone explain this to me? Is it possible to compute the fractional
> power of a negative number? IDL does it on single negative values but
> not on arrays containing negative values.
>
> IDL> print,findgen(11)-5
> -5.00000 -4.00000 -3.00000 -2.00000
> -1.00000 0.000000 1.00000 2.00000
> 3.00000 4.00000 5.00000
> IDL> print,(findgen(11)-5)^1.51
> -1.#IND0 -1.#IND0 -1.#IND0 -1.#IND0
> -1.#IND0 0.000000 1.00000 2.84810
> 5.25355 8.11168 11.3617
> % Program caused arithmetic error: Floating illegal operand
> IDL> print,-2.^1.51
> -2.84810
> IDL> print,-5.^1.51
> -11.3617
>
> Med Bennett
> bennettm@boulder.pti-enviro.com

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[Message index]

		Re: fractional powers of negative numbers? By: thompson on Mon, 28 April 1997 00:00
		Re: fractional powers of negative numbers? By: Jack Saba on Mon, 28 April 1997 00:00
		Re: fractional powers of negative numbers? By: Med Bennett on Thu, 24 April 1997 00:00

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