SmolPRNG

This is a small PRNG library/framwork written in pure Rust, that is a translation of another project of mine, SmallPRNG. The main goal of this project is to not implement every feature possible but to provide a general framework for implmenting PRNG algorithms to test monte carlo codes. This was made primarilly as a educational project of learning Rust and it's features but I hope that this can be used for productive projects like SmallPRNG was.

To live up to the name of SmolPRNG there are less then 1000 lines of code but implements over 22 different algorithms out of the box, can sample from 15 statistical distributions this includes all code + tests + docs + benchs.

SmolPRNG is performance competitive to the Rand Rust crate and is much more straightforward to extend.

Features

• Interface
• PRNG Algorithms
• Generate unsigned ints
• Generate uniform f32,f64
• Distributions (Normal, Beta, Cauchy, Bernoulli, ect)
• Easy seeding of algorithm states
• Benchmarking
• TestU01 Validation

Generate Numbers

Generating random numbers is straight forward after initilizing a PRNG object

let prng = PRNG{generator: JsfGenerator::default()};

let rand_bool = prng.gen_bool(); // Generates a random bool

let rand_u8 = prng.gen_u8();      //Generates a random u8
let rand_u16 = prng.gen_u16();    //Generates a random u16
let rand_u32 = prng.gen_u32();    //Generates a random u32
let rand_u64 = prng.gen_u64();    //Generates a random u64
let rand_u128 = prng.gen_u128();  //Generates a random u128

let rand_f32 = prng.gen_f32();    //Generates a random f32
let rand_f64 = prng.gen_f64();    //Generates a random f64

Implement Your own algorithm

Here is an example of injecting a new algorithm to generate pseudo-random numbers by impl the Algorithm trait on a struct. Availible Outputs are u8,u16,u32,u64,u128.

struct StepGenerator{
  state: u32,
}

impl Algorithm for StepGenerator {
  type Output = u32;

  fn gen(&mut self) -> Self::Output {
    self.data = self.data.overflowing_add(1).0;
    self.data
  }
}

// somewhat gross macro, that adds the traits Iterator, Default, and From<U> where U in {u8, u16, u32, u64, u128}
prng_setup! {StepGenerator, StepGenerator, data, make_1_u32}

Using this, we can then create a PRNG struct from

// create step generator state from output of SplitMix64 algorithm of a u32 seed
let step_generator = StepGenerator::from(12765u32); 
let prng = PRNG{generator: step_generator}

Performance

This is an overview of the performance of the package, running on an intel 12700k CPU. This is categorized as three different benchmarks, generating a 1024 byte buffer filled with random numbers, summing 1 million randomly generated f64 and then 1 million generated f32. The fastest Step generator result is used as a baseline, as this is the algorithm defined by adding 1 and returning state. It is the simplest possible algorithm other than the constant generator.

This is not exhaustive but to cover the broad strokes of the performance characters.

Generating 1024 byte Buffer

Summing 1 million randomly generated f32

Summing 1 million randomly generated f64