RE: ceerano and the seed

[vhamberg@xxxxxxxxx]

Joel

I wonder if there is a side effect of "bucketizing" the
generated random number as you do - it's the standard
technique, I used it to build random strings from
available EBCDIC code points. (I know, there's got to be
a better way, but I was in a hurry.) Even with your
almost 10 trillion values, that's a subset of possible 8-
byte floating point values (about 1/100th?). So even if
the overall distribution is quite random, in a small
sampling (100,000), things could show up more in one
bucket than in others.

But then I'd expect more variation in the frequencies
for each value - not the clumping you report, and that I
believe I've seen, too.

Vern
> Yes and no.  We were multiplying the result to fit into 1 through
> 9,999,999,999,999--i.e. using the leftmost 13 digits of the result.
>
> -----Original Message-----
> From: vhamberg@attbi.com
> To: midrange-l@midrange.com
> Sent: 9/17/2002 11:57 AM
> Subject: RE: ceerano and the seed
>
> Fritz
>
> Are you using the actual floating point values
> generated, or are you extrapolating over a range? If so,
> what is the range?
>
> Vern
> >  I agree that it doesn't work well for what we were trying to do.
> What made
> > me most curious was the pattern of the results.  A small subset of the
> > numbers each occurred 70 and 69 times each with the remainder each
> occurring
> > once over 99,999 iterations. I would have expected something more like
> a
> > normal distribution.
> _______________________________________________
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
> list
> To post a message email: MIDRANGE-L@midrange.com
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/cgi-bin/listinfo/midrange-l
> or email: MIDRANGE-L-request@midrange.com
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.
> NOTICE:
> All e-mail sent to or from this e-mail address will be received or otherwise
> recorded by The Sharper Image corporate e-mail system and is subject to
> archival, monitoring, review by and/or disclosure to Sharper Image security
> and other management. This message is intended only for the use of the
> addressee and may contain information that is privileged and confidential.
> The contents of this message may contain personal views which are not the
> views of The Sharper Image. If you are not the intended recipient,
> dissemination of this communication is prohibited.
> _______________________________________________
> This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list
> To post a message email: MIDRANGE-L@midrange.com
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/cgi-bin/listinfo/midrange-l
> or email: MIDRANGE-L-request@midrange.com
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/midrange-l.
>