So, I looked at your method, t1wc, and I found that it isn't actually evenly distributed. It is significantly more likely to spit out numbers near 0 or near 1 than it is to spit out numbers near 0.5, for example. This is just a consequence of the way that the sine function works.
Instead, you might try using a method called Blum Blum Shub (named after the authors of the original paper, wonderfully). It is evenly distributed and quite fast. Given a seed, it works as follows:
- Square the seed and put the result in a temporary variable (x).
- Take the mod of x base M.
- M is a product of two large primes.
- The value of x is a new seed to be used for future calculations.
- Return x/M as your pseudo-random number. It will be evenly distributed between 0 and 1.
Below is a simple implementation of a Blum Blum Shub:
var SeededRand = function(seed, mod1, mod2)
{
return function()
{
seed = (seed*seed) % (mod1*mod2);
return seed/(mod1*mod2);
};
};
If you want to make a new random number generator, you just call:
var rand = SeededRand(seed, mod1, mod2);
Where seed is some initial seed (1234567890 works well), and mod1 and mod2 are some large primes (7247 and 7823 work well). rand
is just a variable that I've defined to hold the output.
Now, to start getting random values, you just call:
rand();
Which will spit out a different value each time you run it.
If you have any questions, please ask!