The package provides multiple pseudo-random number generators.

Note: The PRNGs generate statistical pseudo-random numbers. They are not cryptographically secure.

Currently implemented generators:

• Seiran128
• SFC64, SFC32

The package is published on Mops and GitHub. Please refer to the README on GitHub where it renders properly with formulas and tables.

API documentation: here on Mops

For updates, help, questions, feedback and other requests related to this package join us on:

• OpenChat group
• Twitter
• Dfinity forum

You need mops installed. In your project directory run:

mops add prng

In the Motoko source file import the generators you need:

import { Seiran128; SFC64; SFC32 } "mo:prng";

(Importing the modules directly — e.g. import Seiran128 "mo:prng/Seiran128" — works too and is required for the rng.next() method-call syntax to resolve.)

The two most commonly used generators from this package are Seiran128 and SFC64a. They both produce Nat64 output values. SFC64a is compatible with numpy.

import { Seiran128; SFC64 } "mo:prng";

let seed : Nat64 = 0;

let rng = Seiran128.new(seed);
let seq : [Nat64] = [rng.next(), rng.next()];

let rng2 = SFC64.SFC64a(seed);
let seq2 : [Nat64] = [rng2.next(), rng2.next()];

The seed argument is optional; omitting it uses each algorithm's default seed:

import { Seiran128; SFC64 } "mo:prng";

let rng = Seiran128.new(); // uses defaultSeiran128Seed
let rng2 = SFC64.SFC64a(); // uses defaultSFC64Seed

There are also two recommended Nat32 generators, SFC32a and SFC32b, used as follows.

import { SFC32 } "mo:prng";

let seed : Nat32 = 0;

let rng = SFC32.SFC32a(seed); // or SFC32.SFC32b(seed)
let seq : [Nat32] = [rng.next(), rng.next()];

For SFC the internal parameters of the generator can also be customized with a constructor like SFC64.new(24, 11, 3, seed). For more details take a look at the test files, the documentation in the source code, or https://mops.one/prng/docs.

Run:

git clone git@github.com:research-ag/prng.git
cd prng
mops test

To format the code, run:

npx -y prettier --plugin prettier-plugin-motoko --write '**/*.{mo,json,md}'

Run

mops bench

The benchmarks were produced with mops bench --replica dfx.

Wasm instructions per invocation of next().

Heap allocation per invocation of next().

MR Research AG, 2023-26

Main author: Timo Hanke (timohanke)

Contributors: Andy Gura (AndyGura), react0r-com

Apache-2.0