RandN.Core 0.2.0

There is a newer version of this package available.
See the version list below for details.
dotnet add package RandN.Core --version 0.2.0
NuGet\Install-Package RandN.Core -Version 0.2.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="RandN.Core" Version="0.2.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add RandN.Core --version 0.2.0
#r "nuget: RandN.Core, 0.2.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install RandN.Core as a Cake Addin
#addin nuget:?package=RandN.Core&version=0.2.0

// Install RandN.Core as a Cake Tool
#tool nuget:?package=RandN.Core&version=0.2.0


RandN on NuGet

RandN is a .NET library for random number generation. It aims to rectify deficiencies in System.Random with adaptability and extensibility in mind. RandN is heavily inspired by the design of the Rust crate rand, and aims to maintain some level of compatibility with it.

What's wrong with System.Random?

In short, the algorithm it uses is slow and biased. The API is very rigid and inflexible, and as a result is unsuited for many purposes.

RandN provides a clear and obvious API that is difficult to use incorrectly, unlike the API of System.Random. This is accomplished by clearly separating two concepts; generating randomness with an IRng, and turning that data into something useful with an IDistribution.


The full documentation is available here.


Install the RandN package from NuGet for most use cases. If you just want to implement an random number generator (ex. you're publishing a package with a new RNG), instead depend on RandN.Core.


Creating an RNG

using RandN;

// Creates a cryptographically secure RNG
var rng = StandardRng.Create();

// Creates a non-cryptographically secure RNG that's fast and uses less memory
var insecureRng = SmallRng.Create();

A reproducible RNG can also be created by using an algorithm directly:

using RandN.Rngs;

// Use ThreadLocalRng to seed the RNG - this uses a cryptographically secure
// algorithm, so tight loops won't result in similar seeds
var seeder = ThreadLocalRng.Instance;

// Create the seed (Seeds can also be created manually)
var factory = ChaCha.GetChaCha8Factory();
var seed = factory.CreateSeed(seeder);

// Create the RNG from the seed
var rng = factory.Create(seed);

Getting random numbers

Once you have an RNG, you can either use it directly,

var num = rng.NextUInt32();
var bigNum = rng.NextUInt64();
var buffer = new Byte[1000];

or you can use it to sample a distribution:

Uniform.Int32 distribution = Uniform.NewInclusive(42, 54); // [42 - 54]
int answer = distribution.Sample(rng);

Bernoulli weightedCoin = Bernoulli.FromRatio(8, 10); // 80% chance of true
bool probablyHeads = weightedCoin.Sample(rng);

Shuffling a list is also easy:

var list = new List<Int32>() { 1, 2, 3, 4, 5, 6 };

Any type implementing IRng can be wrapped with RandomShim, which can be used as a drop-in replacement for Random.

using RandN.Compat;
Random random = RandomShim.Create(rng);
random.Next(2); // returns 0 or 1
Product Compatible and additional computed target framework versions.
.NET net5.0 is compatible.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 is compatible. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (1)

Showing the top 1 NuGet packages that depend on RandN.Core:

Package Downloads

RandN is an alternative library for random number generation, designed to replace the standard Random type.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last updated
0.4.0 10,613 4/4/2023
0.4.0-alpha1 140 4/3/2023
0.3.0 28,173 6/20/2021
0.2.0 7,345 12/21/2020
0.1.0 4,593 6/20/2020
0.1.0-beta 554 6/15/2020

Version 0.2.0

     New APIs:
     The marker-interface IPortableDistribution has been created to mark distributions that provide portable and repeatable results across all platforms. Currently, the Bernoulli, the uniform Decimal, the uniform TimeSpan, and all the uniform integer distributions are portable.
     Added BlockBuffer32<TBlockRng, TBlockCounter>.BlockLength for consistency with BlockBuffer32.BlockLength.

     Updated APIs:
     Uniform distributions now live have been grouped into nested classes under the Uniform static class. For example, UniformInt32 has become Uniform.Int32.
     Unit interval distributions now live in the Rand.Distributions.UnitInterval namespace and have been grouped into nested classes. For example, UnitInterval.OpenDouble has become UnitInterval.Open.Double.
     Method arguments now have null-checks injected by NullGuard.Fody instead of relying on the honor system.
     The TRng type parameter of IRngFactory and IReproducibleRngFactory<TRng, TSeed> is now covariant (IRngFactory<out TRng>).
     BlockBuffer32<TBlockRng>.Length has been renamed to BlockLength.

     Removed APIs:
     Removed the Sample extension methods - these were questionably useful, and could be up to four times slower than their non-extension counterpart, IDistribution.Sample.

     Bug fixes:
     Distributions returning floating point numbers would sometimes sample a number outside the desired range on .NET Framework x86, which can use 80-bit floating point calculations, instead of 64-bit. Results are now forced to 64-bit precision before returning.
     BitwiseExtensions.RotateRight now rotates bits right instead of left on .NET Core 3.1+.
     All places where overflow is expected is now marked with unchecked.