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Re: Math Question [message #51110 is a reply to message #51109]

Mon, 30 October 2006 07:19

edward.s.meinel@aero. is currently offline

edward.s.meinel@aero.
Messages: 52
Registered: February 2005

Member

Rob wrote:
> In general, powers of negative numbers are complex so you should start
> with that assumption in the expression:
>
> IDL> print,(dcomplex(-1.0,0.0))^2.01
> ( 0.99950656, 0.031410729)
> IDL> print,(dcomplex(-1.0,0.0))^2.0
> ( 1.0000000, -2.4492127e-016)
>
> It would be nice if IDL told you this rather than throwing a NaN at
> you.

Actually, to be consistent, IDL should just return a complex number.
One of the reasons that I've been using IDL is that it automatically
changes the variable TYPE when necessary so that I don't have to keep
track of whether I'm operating on a BYTE, LONG, DOUBLE, whatever... Now
I find out that it's "mostly" true (but who can refuse a nice mutton
sandwich?).

I would consider this a bug.

Ed "to blave" Meinel

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[Message index]

		Re: Math Question By: rkombiyil on Wed, 01 November 2006 04:51
		Re: Math Question By: Jo Klein on Tue, 31 October 2006 04:33
		Re: Math Question By: news.qwest.net on Mon, 30 October 2006 13:07
		Re: Math Question By: Jean H. on Mon, 30 October 2006 12:32
		Re: Math Question By: Jean H. on Mon, 30 October 2006 12:35
		Re: Math Question By: Jo Klein on Mon, 30 October 2006 12:17
		Re: Math Question By: Braedley on Mon, 30 October 2006 10:22
		Re: Math Question By: James Kuyper on Mon, 30 October 2006 10:15
		Re: Math Question By: David Fanning on Mon, 30 October 2006 09:19
		Re: Math Question By: James Kuyper on Mon, 30 October 2006 09:04
		Re: Math Question By: news.qwest.net on Mon, 30 October 2006 08:54
		Re: Math Question By: Foldy Lajos on Mon, 30 October 2006 07:29
		Re: Math Question By: edward.s.meinel@aero. on Mon, 30 October 2006 07:19
		Re: Math Question By: Rob Dimeo on Sun, 29 October 2006 16:15
		Re: Math Question By: Robbie on Sun, 29 October 2006 15:40
		Re: Math Question By: Robbie on Sun, 29 October 2006 15:01
		Re: Math Question By: Foldy Lajos on Sun, 29 October 2006 09:59

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