HP41C random number generator help

12082017, 09:56 PM
(This post was last modified: 12082017 10:04 PM by Dieter.)
Post: #24




RE: HP41C random number generator help
(12082017 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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