HP41C random number generator help
12-08-2017, 09:56 PM (This post was last modified: 12-08-2017 10:04 PM by Dieter.)
Post: #24
 Dieter Senior Member Posts: 2,397 Joined: Dec 2013
RE: HP41C random number generator help
(12-08-2017 09:17 PM)Trond Wrote:  I guess I missed the 1, 3, 7, 9 part, but yes I meant beyond the sixth decimal (do we have this written down somewhere? You seemed uncertain too).

As already noted, an article in PPC Journal V4N8 by Victor K. Heyman takes a close look at four popular PRNGs, among them the 997x generator. The article mentions 11 different tests, even some quite sophisticated ones. Here it says:

Quote:With the proper seed, this generator has a cylce of 500,000 iterations. HP chose pretty well when it selected .5284163. It is supposed to pass all standard tests, and with a blink or two, it does. That is a tough seed to remember, and worse to program, so I have found one that is as good and much easier on the user: Pi, Sin, Tan. It works, and also follows all the rules -- the seed must have seven digits after multiplying by 997, the 7th not divisible by 2 or 5. (...) However every seed that meets the rule is not good.

"Not divisible by 2 or 5" means 1, 3, 7 or 9 for the seed's last digit. And that's exactly what the 997x generator produces.

Dieter
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 Messages In This Thread HP41C random number generator help - Trond - 12-05-2017, 05:45 AM RE: HP41C random number generator help - Paul Dale - 12-05-2017, 05:52 AM RE: HP41C random number generator help - Trond - 12-05-2017, 06:02 AM RE: HP41C random number generator help - Paul Dale - 12-05-2017, 06:06 AM RE: HP41C random number generator help - Dieter - 12-05-2017, 08:31 AM RE: HP41C random number generator help - Sylvain Cote - 12-05-2017, 06:08 AM RE: HP41C random number generator help - Trond - 12-05-2017, 06:33 AM RE: HP41C random number generator help - Trond - 12-05-2017, 10:25 PM RE: HP41C random number generator help - Trond - 12-05-2017, 06:12 AM RE: HP41C random number generator help - Dieter - 12-05-2017, 08:23 AM RE: HP41C random number generator help - Namir - 12-05-2017, 12:30 PM RE: HP41C random number generator help - Trond - 12-05-2017, 03:24 PM RE: HP41C random number generator help - Dieter - 12-05-2017, 06:54 PM RE: HP41C random number generator help - Trond - 12-05-2017, 07:50 PM RE: HP41C random number generator help - Dieter - 12-05-2017, 08:11 PM RE: HP41C random number generator help - Trond - 12-08-2017, 04:26 AM RE: HP41C random number generator help - Dieter - 12-08-2017, 07:43 PM RE: HP41C random number generator help - Trond - 12-08-2017, 09:17 PM RE: HP41C random number generator help - Dieter - 12-08-2017 09:56 PM RE: HP41C random number generator help - Mike T. - 12-21-2021, 07:09 PM RE: HP41C random number generator help - Dieter - 12-09-2017, 09:53 PM RE: HP41C random number generator help - Trond - 12-10-2017, 04:09 AM RE: HP41C random number generator help - ttw - 12-05-2017, 01:43 PM RE: HP41C random number generator help - Trond - 12-05-2017, 03:53 PM RE: HP41C random number generator help - Thomas Okken - 12-05-2017, 05:21 PM RE: HP41C random number generator help - Trond - 12-05-2017, 06:32 PM RE: HP41C random number generator help - Garth Wilson - 12-05-2017, 07:33 PM RE: HP41C random number generator help - Trond - 12-21-2021, 06:25 AM RE: HP41C random number generator help - ttw - 12-22-2021, 03:58 AM RE: HP41C random number generator help - John Keith - 12-22-2021, 07:02 PM

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