If you look in a book most of which is available on line called "Numerical Recipes in C", then you can probably pull out the receipe for a random number generator such as rand1 or rand2.
Those should be perlable -~.-~.-~.-~.-~.-~.-~.-~.-~.-~ -~ -~ Cliff Frensley -~ [EMAIL PROTECTED] -~ Seattle, WA -~ -~ -. On Tue, 28 Jan 2003, Cliff wrote: > There is a perl function "exp" - that is, the natural exponential function. A > Gaussian bell curve is defined by a function like: > > y(x) = A*exp( ((x-s)/t)^2) > > The exact functional form I just typed might be incorrect, look up the exact > function in any basic math, science, or statistics text. Look it up online. > > The parameter "A" is an amplitude scaling function or variable, x is a domain > ordinate, t is something that gets called "time constant" in the science world, > and s is (as my rusty memory produces) a mean or central value for the > distribution. The exponent term, that is, the squared term, produces the > standard deviation. > > Use that standard deviation to control the distribution around the mean, that > is, the "narrow" or "broad" aspect of the bell-shaped curve. > > The point is, it is easy to *implement* the function in perl. The exact usage of > the bell curve in producing a distribution can be understood better than my > rusty memory can produce by about 20 minutes of examination of any text or even > likely any of a number of web sites out there. > > Best of luck, you should'nt need much - > > -~.-~.-~.-~.-~.-~.-~.-~.-~.-~ > -~ > -~ Cliff Frensley > -~ [EMAIL PROTECTED] > -~ Seattle, WA > -~ > -~ > -. > > On Tue, 28 Jan 2003, Russ Foster wrote: > > > Want to give any hints on how to accomplish this in Perl? > > > > -----Original Message----- > > From: Cliff [mailto:[EMAIL PROTECTED]] > > Sent: Tuesday, January 28, 2003 11:04 AM > > To: Russ Foster > > Cc: '[EMAIL PROTECTED]' > > Subject: Re: Bell Curves and Random numbers > > > > > > Ultimately, the distribution is shaped and determined by your distribution > > function. > > > > In your bell curve, you need to reduce the size of the standard deviation, > > that > > is, sigma in the exponent. You can do that fairly simply by simply making > > the > > guassian standard deviation sigma an input parameter into your randomizing > > function. > > > > The smaller the standard deviation, the tighter the bell curve. Definately > > not a > > perl specific question. > > > > -~.-~.-~.-~.-~.-~.-~.-~.-~.-~ > > -~ > > -~ Cliff Frensley > > -~ [EMAIL PROTECTED] > > -~ Seattle, WA > > -~ > > -~ > > -. > > > > On Tue, 28 Jan 2003, Russ Foster wrote: > > > > > I'm looking to generate a bunch of random information to be used for > > > testing. > > > > > > Right now, my script accepts three parameters, quantity, a central point, > > > and a deviation range and then generates [quantity] numbers ranging from > > > [central point - deviation range] to [central point + deviation range]. > > > > > > so it looks like this: > > > > > > perl GenNumbers.pl 10 100 5 > > > 95 > > > 102 > > > 99 > > > 100 > > > . > > > . > > > 101 > > > > > > Unfortunately this generates a rather flat distribution--numbers evenly > > > distributed from 95-105. Ideally, I'd like the majority of numbers to be > > > "closer" to the central point, with relatively few at the extremes. > > > > > > Any ideas on how to go about doing this? > > > > > > Now that I've written this up, I suppose it may be more of a math question > > > and Perl related. The only statistic related modules I can find are more > > > formulae based and don't help in generating numbers. > > > > > > If it matters, I'm using perl v5.6.1 for Cygwin. I do have access to > > > ActiveState perl if it's necessary. > > > > > > Thanks. > > > > > > -r > > > > > > Russell J Foster > > > Senior Systems Engineer > > > Subject, Wills, and Company > > > _______________________________________________ > > > Perl-Win32-Admin mailing list > > > [EMAIL PROTECTED] > > > To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs > > > > > > > _______________________________________________ > > Perl-Win32-Admin mailing list > > [EMAIL PROTECTED] > > To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs > > > > _______________________________________________ > Perl-Win32-Admin mailing list > [EMAIL PROTECTED] > To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs > _______________________________________________ Perl-Win32-Admin mailing list [EMAIL PROTECTED] To unsubscribe: http://listserv.ActiveState.com/mailman/mysubs
