comp.lang.idl-pvwave archive: archive » Re: Randomize array order

Home » Public Forums » archive » Re: Randomize array order

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

Re: Randomize array order [message #54990 is a reply to message #54988]

Fri, 27 July 2007 14:29

James Kuyper
Messages: 425
Registered: March 2000

Senior Member

David Streutker wrote:
...
> If there are only 2^32 possible sequences, then why is the internal
> state characterized by a 36-element array?
>
> IDL> test = randomu(seed)
> IDL> help, seed
> SEED LONG = Array[36]

That is a VERY good question. I only looked at the documentation; I
didn't bother to check. The documentation says:

> The state of the random number generator is contained in a long integer vector.

and also

> If the Seed argument is:
> * an undefined variable - the generic state is used and the resulting generic state array is stored in the variable.

Given that the resulting generic state appears to be a 36-element
array, I don't think both statements can be true. An array of 36 longs
would be more than enough to generate all possible shuffles of a 52-
card deck. More importantly, it's large enough to do large numerical
simulations in quantum field theory without introducing spurious
correlations. Therefore I hope that the second statement is the one
that's correct.

Report message to a moderator

[Message index]

		Re: Randomize array order By: Michael Galloy on Fri, 27 July 2007 15:35
		Re: Randomize array order By: James Kuyper on Fri, 27 July 2007 14:29
		Re: Randomize array order By: Conor on Fri, 27 July 2007 11:09
		Re: Randomize array order By: David Streutker on Fri, 27 July 2007 10:54
		Re: Randomize array order By: Conor on Fri, 27 July 2007 09:44
		Re: Randomize array order By: James Kuyper on Fri, 27 July 2007 09:29
		Re: Randomize array order By: James Kuyper on Fri, 27 July 2007 09:05
		Re: Randomize array order By: David Streutker on Fri, 27 July 2007 07:54
		Re: Randomize array order By: Paolo Grigis on Fri, 27 July 2007 06:59
		Re: Randomize array order By: Allan Whiteford on Fri, 27 July 2007 05:03
		Re: Randomize array order By: Allan Whiteford on Fri, 27 July 2007 02:33
		Re: Randomize array order By: David Streutker on Thu, 26 July 2007 14:27
		Re: Randomize array order By: Vince Hradil on Thu, 26 July 2007 13:32
		Re: Randomize array order By: David Streutker on Thu, 26 July 2007 09:57
		Re: Randomize array order By: Conor on Thu, 26 July 2007 09:22
		Re: Randomize array order By: Allan Whiteford on Thu, 26 July 2007 08:49
		Re: Randomize array order By: Vince Hradil on Thu, 26 July 2007 08:13
		Re: Randomize array order By: Vince Hradil on Thu, 26 July 2007 07:58
		Re: Randomize array order By: Conor on Thu, 26 July 2007 06:40
		Re: Randomize array order By: Allan Whiteford on Thu, 26 July 2007 06:30
		Re: Randomize array order By: Brian Larsen on Thu, 26 July 2007 06:06
		Re: Randomize array order By: Brian Larsen on Thu, 26 July 2007 06:04
		Re: Randomize array order By: mattf on Thu, 26 July 2007 05:50
		Re: Randomize array order By: Conor on Thu, 26 July 2007 05:28
		Re: Randomize array order By: Conor on Thu, 26 July 2007 05:24
		Re: Randomize array order By: Vince Hradil on Wed, 25 July 2007 12:59

Previous Topic:	Re: Routine for Converting DN to Radiance to Temperature
Next Topic:	Re: Socket server in > IDL 6.3

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 18:16:51 PDT 2025

Total time taken to generate the page: 0.00273 seconds