comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Re: randomn problem

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

Re: randomn problem [message #52955 is a reply to message #52954]

Sun, 11 March 2007 12:41

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

askemer@gmail.com writes:

> I was playing around with randomn and noticed some weird behavior:
>
> IDL> print, stddev(randomn(seed, 1e7))
>
> I consistently get back numbers around ~0.992. I've tried it on a
> different computer, and the result was not exactly the same, but
> similar. If I change 1e7 to 1e8, the problem gets worse, and I get
> ~0.853. I've tried the syntax with floats, integers, and longs, and I
> still get the same answer. Does anyone know what could be going on?

IDL> print, !version
{ x86 Win32 Windows Microsoft Windows 6.3 Mar 23 2006 32 64}

IDL> print, stddev(randomn(seed, 1e7))
0.999961
IDL> print, stddev(randomn(seed, 1e7, /double))
1.0000060

Don't know. :-(

Cheers,

David
--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Report message to a moderator

[Message index]

		Re: randomn problem By: Ben Panter on Mon, 12 March 2007 09:17
		Re: randomn problem By: Nigel Wade on Mon, 12 March 2007 09:07
		Re: randomn problem By: Paolo Grigis on Mon, 12 March 2007 02:07
		Re: randomn problem By: Ingo von Borstel on Mon, 12 March 2007 01:03
		Re: randomn problem By: David Fanning on Sun, 11 March 2007 18:10
		Re: randomn problem By: askemer on Sun, 11 March 2007 16:04
		Re: randomn problem By: David Fanning on Sun, 11 March 2007 12:41
		Re: randomn problem By: JD Smith on Tue, 13 March 2007 09:25
		Re: randomn problem By: Paolo Grigis on Tue, 13 March 2007 04:03

Previous Topic:	Re: New IDLDE
Next Topic:	Delete bad data and interplate the new data

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 09:44:15 PDT 2025

Total time taken to generate the page: 0.96047 seconds