From 8ffd9ab48a643f1dde82a8b8e19145593ed4ece1 Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Wed, 30 Nov 2022 00:24:43 +0100
Subject: [PATCH] improved and cleaned up SingleRandom

---
 MLEM/Misc/SingleRandom.cs  | 20 ++++++++++++--------
 Tests/SingleRandomTests.cs | 13 ++++++-------
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/MLEM/Misc/SingleRandom.cs b/MLEM/Misc/SingleRandom.cs
index 8e5bcdf..4b35100 100644
--- a/MLEM/Misc/SingleRandom.cs
+++ b/MLEM/Misc/SingleRandom.cs
@@ -24,7 +24,7 @@ namespace MLEM.Misc {
         /// </summary>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static int Int(int[] seeds) {
+        public static int Int(params int[] seeds) {
             return (int) (SingleRandom.Single(seeds) * int.MaxValue);
         }
 
@@ -46,7 +46,7 @@ namespace MLEM.Misc {
         /// <param name="maxValue">The (exclusive) maximum value.</param>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static int Int(int maxValue, int[] seeds) {
+        public static int Int(int maxValue, params int[] seeds) {
             return (int) (maxValue * SingleRandom.Single(seeds));
         }
 
@@ -70,7 +70,7 @@ namespace MLEM.Misc {
         /// <param name="maxValue">The (exclusive) maximum value.</param>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static int Int(int minValue, int maxValue, int[] seeds) {
+        public static int Int(int minValue, int maxValue, params int[] seeds) {
             return (int) ((maxValue - minValue) * SingleRandom.Single(seeds)) + minValue;
         }
 
@@ -90,7 +90,7 @@ namespace MLEM.Misc {
         /// </summary>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static float Single(int[] seeds) {
+        public static float Single(params int[] seeds) {
             return (SingleRandom.Scramble(seeds) / (float) int.MaxValue + 1) / 2;
         }
 
@@ -112,7 +112,7 @@ namespace MLEM.Misc {
         /// <param name="maxValue">The (exclusive) maximum value.</param>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static float Single(float maxValue, int[] seeds) {
+        public static float Single(float maxValue, params int[] seeds) {
             return maxValue * SingleRandom.Single(seeds);
         }
 
@@ -136,20 +136,24 @@ namespace MLEM.Misc {
         /// <param name="maxValue">The (exclusive) maximum value.</param>
         /// <param name="seeds">The seeds to use.</param>
         /// <returns>The generated number.</returns>
-        public static float Single(float minValue, float maxValue, int[] seeds) {
+        public static float Single(float minValue, float maxValue, params int[] seeds) {
             return (maxValue - minValue) * SingleRandom.Single(seeds) + minValue;
         }
 
         private static int Scramble(int[] seeds) {
             if (seeds == null || seeds.Length <= 0)
                 throw new ArgumentOutOfRangeException(nameof(seeds));
-            var ret = 1;
+            var ret = 1623487;
             for (var i = 0; i < seeds.Length; i++)
-                ret *= SingleRandom.Scramble(seeds[i]);
+                ret += SingleRandom.ScrambleStep(seeds[i]) * 68659;
             return ret;
         }
 
         private static int Scramble(int seed) {
+            return SingleRandom.ScrambleStep(seed) * 68659 + 1623487;
+        }
+
+        private static int ScrambleStep(int seed) {
             seed ^= (seed << 7);
             seed *= 207398809;
             seed ^= (seed << 17);
diff --git a/Tests/SingleRandomTests.cs b/Tests/SingleRandomTests.cs
index 5795886..ae28aa3 100644
--- a/Tests/SingleRandomTests.cs
+++ b/Tests/SingleRandomTests.cs
@@ -16,8 +16,8 @@ public class SingleRandomTests {
             // test if all methods that accept mins and max are identical
             Assert.AreEqual(SingleRandom.Int(i), SingleRandom.Int(int.MaxValue, i));
             Assert.AreEqual(SingleRandom.Int(i), SingleRandom.Int(0, int.MaxValue, i));
-            Assert.AreEqual(SingleRandom.Single(i), SingleRandom.Single(1, i));
-            Assert.AreEqual(SingleRandom.Single(i), SingleRandom.Single(0, 1, i));
+            Assert.AreEqual(SingleRandom.Single(i), SingleRandom.Single(1F, i));
+            Assert.AreEqual(SingleRandom.Single(i), SingleRandom.Single(0F, 1F, i));
         }
     }
 
@@ -25,8 +25,8 @@ public class SingleRandomTests {
     public void TestBounds() {
         for (var i = 0; i < 1000000; i++) {
             Assert.That(SingleRandom.Single(i), Is.LessThan(1).And.GreaterThanOrEqualTo(0));
-            Assert.That(SingleRandom.Single(127, i), Is.LessThan(127).And.GreaterThanOrEqualTo(0));
-            Assert.That(SingleRandom.Single(12920, 1203919023, i), Is.LessThan(1203919023).And.GreaterThanOrEqualTo(12920));
+            Assert.That(SingleRandom.Single(127F, i), Is.LessThan(127).And.GreaterThanOrEqualTo(0));
+            Assert.That(SingleRandom.Single(12920F, 1203919023F, i), Is.LessThan(1203919023).And.GreaterThanOrEqualTo(12920));
 
             Assert.That(SingleRandom.Int(i), Is.LessThan(int.MaxValue).And.GreaterThanOrEqualTo(0));
             Assert.That(SingleRandom.Int(17, i), Is.LessThan(17).And.GreaterThanOrEqualTo(0));
@@ -42,9 +42,8 @@ public class SingleRandomTests {
             ints.Add(SingleRandom.Int(i));
             flts.Add(SingleRandom.Single(i));
         }
-        // allow being off by 0.00001 of the total
-        Assert.AreEqual(ints.Average(), int.MaxValue / 2, 0.00001 * int.MaxValue);
-        Assert.AreEqual(flts.Average(), 0.5, 0.00001);
+        Assert.AreEqual(0.5, ints.Average() / int.MaxValue, 0.001);
+        Assert.AreEqual(0.5, flts.Average(), 0.001);
     }
 
 }