From 1651fbaa2bcab796eaf641ef3d103ba15a8f3a26 Mon Sep 17 00:00:00 2001
From: Thorsten Sommer <mail@tsommer.org>
Date: Sat, 31 Oct 2020 23:49:37 +0100
Subject: [PATCH] Added float implementations

---
 FastRng/Float/Distributions/BetaA2B2.cs     | 13 ++++++++
 FastRng/Float/Distributions/BetaA2B5.cs     | 13 ++++++++
 FastRng/Float/Distributions/BetaA5B2.cs     | 13 ++++++++
 FastRng/Float/Distributions/Distribution.cs | 34 +++++++++++++++++++++
 4 files changed, 73 insertions(+)
 create mode 100644 FastRng/Float/Distributions/BetaA2B2.cs
 create mode 100644 FastRng/Float/Distributions/BetaA2B5.cs
 create mode 100644 FastRng/Float/Distributions/BetaA5B2.cs
 create mode 100644 FastRng/Float/Distributions/Distribution.cs

diff --git a/FastRng/Float/Distributions/BetaA2B2.cs b/FastRng/Float/Distributions/BetaA2B2.cs
new file mode 100644
index 0000000..d533d96
--- /dev/null
+++ b/FastRng/Float/Distributions/BetaA2B2.cs
@@ -0,0 +1,13 @@
+using System;
+
+namespace FastRng.Float.Distributions
+{
+    public sealed class BetaA2B2 : Distribution
+    {
+        private const float ALPHA = 2f;
+        private const float BETA = 2f;
+        private const float CONSTANT = 4f;
+
+        protected override float ShapeFunction(float x) => CONSTANT * MathF.Pow(x, ALPHA - 1f) * MathF.Pow(1f - x, BETA - 1f);
+    }
+}
\ No newline at end of file
diff --git a/FastRng/Float/Distributions/BetaA2B5.cs b/FastRng/Float/Distributions/BetaA2B5.cs
new file mode 100644
index 0000000..d3ea994
--- /dev/null
+++ b/FastRng/Float/Distributions/BetaA2B5.cs
@@ -0,0 +1,13 @@
+using System;
+
+namespace FastRng.Float.Distributions
+{
+    public sealed class BetaA2B5 : Distribution
+    {
+        private const float ALPHA = 2f;
+        private const float BETA = 5f;
+        private const float CONSTANT = 12.2f;
+
+        protected override float ShapeFunction(float x) => CONSTANT * MathF.Pow(x, ALPHA - 1f) * MathF.Pow(1f - x, BETA - 1f);
+    }
+}
\ No newline at end of file
diff --git a/FastRng/Float/Distributions/BetaA5B2.cs b/FastRng/Float/Distributions/BetaA5B2.cs
new file mode 100644
index 0000000..79fbc45
--- /dev/null
+++ b/FastRng/Float/Distributions/BetaA5B2.cs
@@ -0,0 +1,13 @@
+using System;
+
+namespace FastRng.Float.Distributions
+{
+    public sealed class BetaA5B2 : Distribution
+    {
+        private const float ALPHA = 5f;
+        private const float BETA = 2f;
+        private const float CONSTANT = 12.2f;
+
+        protected override float ShapeFunction(float x) => CONSTANT * MathF.Pow(x, ALPHA - 1f) * MathF.Pow(1f - x, BETA - 1f);
+    }
+}
\ No newline at end of file
diff --git a/FastRng/Float/Distributions/Distribution.cs b/FastRng/Float/Distributions/Distribution.cs
new file mode 100644
index 0000000..47a86ce
--- /dev/null
+++ b/FastRng/Float/Distributions/Distribution.cs
@@ -0,0 +1,34 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace FastRng.Float.Distributions
+{
+    public abstract class Distribution : IDistribution
+    {
+        private ShapeFitter fitter;
+        private IRandom random;
+        
+        public IRandom Random
+        {
+            get => this.random;
+            set
+            {
+                if(this.random != null)
+                    return;
+                
+                this.random = value;
+                this.fitter = new ShapeFitter(this.ShapeFunction, this.random, 100);
+            }
+        }
+
+        protected abstract float ShapeFunction(float x);
+        
+        public async ValueTask<float> GetDistributedValue(CancellationToken token = default)
+        {
+            if (this.Random == null)
+                return float.NaN;
+            
+            return await this.fitter.NextNumber(token);
+        }
+    }
+}
\ No newline at end of file