comp.lang.idl-pvwave archive: archive » Cubic root finding on a grid

Home » Public Forums » archive » Cubic root finding on a grid

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

Re: cubic root [message #83963 is a reply to message #68737]

Tue, 16 April 2013 08:27

wlandsman
Messages: 743
Registered: June 2000

Senior Member

You can also use FZ_ROOTS to get all 3 roots to the equation x^3 + 1 = 0

IDL> print,fz_roots([1,0d,0,1.0d])
( -1.0000000, 0.0000000)( 0.50000000, -0.86602540)( 0.50000000, 0.86602540)

or use http://idlastro.gsfc.nasa.gov/ftp/contrib/freudenreich/cuber oot.pro

On Tuesday, April 16, 2013 11:08:12 AM UTC-4, fd_...@mail.com wrote:
> Hi all
>
>
>
> I have a question about cubic roots. The cubic roots of a negative number there exists. The cubir root of -1 is -1, 0f -2 is -1.25 and so on why when I typed in IDL to calculate the cubic root of a negative value it print out NaN which means Not a Number?
>
>
>
> E.g. I typed: (-1)^1.0/3 and it prints out NaN
>
>
>
> Is there any way to fixed it and don't get NaNs but get the actual value?
>
>
>
> Best Wishes
>
> Maria

Report message to a moderator

[Message index]

		Cubic root finding on a grid By: Luds on Fri, 20 November 2009 08:03
		Re: cubic root By: Lajos Foldy on Tue, 16 April 2013 09:44
		Re: cubic root By: wlandsman on Tue, 16 April 2013 08:27
		Re: cubic root By: Lajos Foldy on Tue, 16 April 2013 08:19

Previous Topic:	Re: Finding distance with longitude and latitude
Next Topic:	All logical unit currently in use

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 14:17:46 PDT 2025

Total time taken to generate the page: 0.23931 seconds