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How good is Rand()?
Message
De
23/01/2008 10:28:05
James Beerbower
James Beerbower Enterprises
Hochheim Am Main, Allemagne
 
 
À
23/01/2008 09:21:02
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
01284415
Message ID:
01284471
Vues:
15
Thanks for the advice! I'm still hoping someone out there has rigorously tested rand() and can give me some information before I try to find a new random number generator... Cause I'm lazy and no good ;-)


>>Hi all!
>>
>>Looking through my copy of "Numerical Recipes" I read the following:
>>
>>"Never use a generator based on a linear congruential generator (LCG) or a multiplicative linear congruential generator (MLCG)"
>>
>>"Never use a generator with a period less 2**64 or any generator whose period is undisclosed"
>>
>>I use the rand() function to generate control groups (select 10.000 random customers from 100.000 ...) and reading the above gave me a stomach ache.
>>
>>Does anyone know more about rand() in VFP? I saw one MSDN post from Tamara that said "it seemed pretty good" But that leaves a lot of room open. Thanks in advance for your collective wisdom!
>
>For day to day use of simple random sampling for very finite numbers (get 500 people for mailing) and so on I think it is fine. I would not do any Monte-Carlo-Studies based on it and not base a gambling site on it. I'ld also hesitate to compare very large samplings to artifical compare groups.
>
>HTH
>
>thomas
>
>BTW: what line of work are you here in "my" town <g>?
James Beerbower
James Beerbower Enterprises
Frankfurt, Deutschland
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