http://www.jsoftware.com/jwiki/Essays/RNG
----- Original Message ----- From: Ralph G Selfridge <[EMAIL PROTECTED]> Date: Wednesday, September 12, 2007 11:26 Subject: [Jgeneral] Random numbers To: [email protected] > I really haven't looked enough at Roger's material on his random > number > generator but the following seems to me to be necessary. > > The output sequence depends on the inital state. Now it becomes > important > to start some large number of steps down that sequence, where > the > 'distance' is easily set. This allows you to return to the same > position > in the sequence for testing, but also allows different users to > have an > easily controlled different starting point. > > When I read of a starting seed I wonder if I have only two > choices, start > with that seed or run some artifical number of hits on the > generator. I > suppose you can set the seed 'randomly' but that doesn't change > the other > 'hidden' numbers behind the generator. > > I don't have a good answer, and one of Roger's comments did > address a > generator like this of mine (there were better ones around). > There are four > inherent loops in the generator and you can specify the number > of times > each loop gets hit, and still have an easy way to return to your > starting > point. These loops control the internal machinations so that > different > users start differently. An earlier article about generators > pointed out > that it important to have members of a group using the same > generator but > different sequences. > > I am reminded of this only by recent comments about '?' or '?.' ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
