Re: ceerano and the seed

[Vernon Hamberg <vhamberg@xxxxxxxxx>]

Try a seed of "roxanne"

Sorry - couldn't resist.

I have found the same thing. Try using 0 for the seed each time - then it
generates its own seed from the Greenwich Mean Time.

I've tried various schemes. I incremented the returned seed by 1, testing
for overflow after to 2,147,483,646. But I don't know enough about the
method used, the "multiplicative congruential" method, according to the API
manual.

There are other random number generators on the 400. One is the rand()
function of C/C++. There is also the CIPHER MI instruction - it is exposed
to use in ILE programs. Lots of luck finding documentation. I'll look in my
MI reference - but Leif might know something here. I think it generates a
key - it might be possible to interpret it as other data types.

There's also one in later versions of SQL.

At 04:06 PM 9/16/02 -0700, you wrote:
> We've been playing with CEERANO to try to construct a list of 13 digit
> unique numbers in "random" order.  It looks like that after 20,000 or so,
> diminishing returns sets in in a big way.
>
> What we're doing is starting with zero as the seed and using whatever gets
> returned in the seed parm as the next seed.  The test program looks at its
> output file to see if the current random number is in the file.  If not, it
> writes it.  Out of curiosity I tried a run of 99,999--off by 1 <g>--just to
> see what I'd get.  1322 of the numbers occurred 70 times, 29 of them
> occurred 69 times, and the others occurred once.  I guess I'd expect the
> frequencies to be a little more normally distributed.
>
> Looks like using the seed value returned by the function is not a good idea.
> Does anyone know what's happening here?