New Lagged Fib. PRNG gen and random2.d

[bearophile]

monarch_dodra:

> The Lagged Fibonacci generator has interesting properties: For 
> starters, you can generate integers or floats with it. With 
> floats, it generates numbers in a 0 .. 1 range, making it a 
> very nice generator for users that want simple uniform floating 
> point generation in that range.

What is its relative performance (measured with LDC2 and/or GDC) 
compared to Xorshift and the Mersenne Twister when it is used to 
generate integers and when it's used to generate floating point 
numbers in 0..1 (for the floating point case you have to use 
something like random01 to have a fair comparison)?


> In terms of quality, I'm no expert, but supposedly, it's 
> supposed to be good, when properly seeded.

Before being merged into Phobos someone has to measure a bit the 
actual quality of the random numbers it produces. To avoid 
problems like the ones had with Xorshift. There are suites and 
tools to measure the quality of random numbers, like a more 
modern version of the famous diehard.

Bye,
bearophile