Random Number Generators

[Silencer]

How do they work?

 

I heard that equations based on the seed value are used. If so, do you have any examples of them?

[mezarashi]

Yeah, alot. You get to see them generally when you're doing programming. It's probably a very intersting topic in computer science. They are more precisely known as psuedo random number generators though, because they are not truly random. A truly random number generator would have to be both unpredictable and unreproducable. This is probably not achievable by us anytime soon until we can get a hold of quantum computers maybe The point being is that we will always know the algorithm we used to generate the numbers so knowing that its obvious that we will know the next generated number.

 

It may let you down to know that most of these random number generators are REproducable, yes. Given any particle seed, you will get the same list of random numbers everytime. They do work however, because the successive numbers will appear to be random, but they distribute themselves evenly over a long range. The "better" a generator is, the longer its period is. That is say, most generators, after 500 billion numbers, will start to look periodic, thus not random anymore. You may be asking, then why use them. That's because if for example your random number generator has a cycle of 500 trillion numbers, and you only need 100 samples for your experiment, then your generator will indeed appear random. Depending on your practical application, you may need to look at different generators.

 

Oops forgot to post a link to some C++ generators:

http://www.agner.org/random

[Deified]

Thats why in programming you often seed a generator to a mildly unpredictable number, such as the number of milliseconds since the computer was booted.

[Supaiku]

http://www.rednova.com/news/display/?id=126649#121

How's that random number generator work?

[ed84c]

http://www.scienceforums.net/forums/showthread.php?t=7220&highlight=random+numbers