FastRng/FastRngTests/Distributions/BetaA5B2.cs

using System;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using FastRng;
using NUnit.Framework;

namespace FastRngTests.Distributions;

[ExcludeFromCodeCoverage]
public class BetaA5B2
{
    [Test]
    [Category(TestCategories.COVER)]
    [Category(TestCategories.NORMAL)]
    public void TestBetaDistribution01()
    {
        using var rng = new MultiThreadedRng<float>();
        var dist = new FastRng.Distributions.BetaA5B2<float>(rng);
        var fqa = new FrequencyAnalysis();

        for (var n = 0; n < 100_000; n++)
            fqa.CountThis(dist.NextNumber());
            
        var result = fqa.NormalizeAndPlotEvents(TestContext.WriteLine);
            
        Assert.That(result[0], Is.EqualTo(0.0000001f).Within(0.0000003f));
        Assert.That(result[1], Is.EqualTo(0.0000019f).Within(0.00001f));
        Assert.That(result[2], Is.EqualTo(0.0000096f).Within(0.0004f));

        Assert.That(result[21], Is.EqualTo(0.0222918f).Within(0.03f));
        Assert.That(result[22], Is.EqualTo(0.0262883f).Within(0.03f));
        Assert.That(result[23], Is.EqualTo(0.0307623f).Within(0.03f));
            
        Assert.That(result[50], Is.EqualTo(0.4044237f).Within(0.2f));
            
        Assert.That(result[75], Is.EqualTo(0.9768445f).Within(0.15f));
        Assert.That(result[85], Is.EqualTo(0.9552714f).Within(0.15f));
        Assert.That(result[90], Is.EqualTo(0.8004420f).Within(0.35f));
            
        Assert.That(result[97], Is.EqualTo(0.2250578f).Within(0.03f));
        Assert.That(result[98], Is.EqualTo(0.1171927f).Within(0.03f));
        Assert.That(result[99], Is.EqualTo(0f).Within(0.0004f));
    }
        
    [Test]
    [Category(TestCategories.COVER)]
    [Category(TestCategories.NORMAL)]
    public void TestBetaGeneratorWithRange01()
    {
        using var rng = new MultiThreadedRng<float>();
        var samples = new float[1_000];
        var dist = new FastRng.Distributions.BetaA5B2<float>(rng);
        for (var n = 0; n < samples.Length; n++)
            samples[n] = dist.NextNumber(-1.0f, 1.0f);

        Assert.That(samples.Min(), Is.GreaterThanOrEqualTo(-1.0f), "Min out of range");
        Assert.That(samples.Max(), Is.LessThanOrEqualTo(1.0f), "Max out of range");
    }
        
    [Test]
    [Category(TestCategories.COVER)]
    [Category(TestCategories.NORMAL)]
    public void TestBetaGeneratorWithRange02()
    {
        using var rng = new MultiThreadedRng<float>();
        var samples = new float[1_000];
        var dist = new FastRng.Distributions.BetaA5B2<float>(rng);
        for (var n = 0; n < samples.Length; n++)
            samples[n] = dist.NextNumber(0.0f, 1.0f);
            
        Assert.That(samples.Min(), Is.GreaterThanOrEqualTo(0.0f), "Min is out of range");
        Assert.That(samples.Max(), Is.LessThanOrEqualTo(1.0f), "Max is out of range");
    }

    [Test]
    [Category(TestCategories.COVER)]
    [Category(TestCategories.NORMAL)]
    public void NoRandomNumberGenerator01()
    {
        Assert.Throws<ArgumentNullException>(() => new FastRng.Distributions.BetaA5B2<float>(null));
    }
}