
Vernon, Yes, I am talking about the theory of generating pseudorandom numbers. I did a lot of work with these when I was doing Processing Plant Simulations and Statistical Process Control a long time ago with General Foods. So, hopefully CEERAN0 uses GMT in the form HHMMSSTHT and then multiplies by 8 and adds 1 to get a large odd seed (since odd numbers have a chance of being prime). Peter.  Original Message  From: "Vernon Hamberg" <vhamberg@attbi.com> To: <midrangel@midrange.com> Sent: Tuesday, September 17, 2002 12:05 AM Subject: Re: ceerano and the seed > Peter > > I'm not sure of the context. The usage instructions for CEERAN0 say that > the seed should be a nonnegative integer between 0 and 2,147,483,646. Zero > makes it generate its own seed from the GMT at the time the function is > called. And it returns a value that can be used as the next seed. Of > course, the new seed is generated by the original process, hence, as Leif > says, it might not be that good an idea to use it. That was why I suggested > using 0, as that forces a somewhat unpredictable value for the seed each time. > > Are you speaking of the theory of generating pseudorandom numbers, that > uses a couple large relatively prime numbers? Am I anywhere close? I've > never studied the theory that closely, I just want a function I can use > that I can trust to generate even distributions. > > The rand() function in SQL can take a seed or not. Without a seed (a > smallint or integer) it must generate its own seed, as it starts with a > different sequence each time. If you use a seed, such as rand(100), the > sequence of random floating point numbers is the same each time, as is > expected. CEERAN0 has the same behavior > > Vern