Changeset 17707 for branches/2825-NSGA3/HeuristicLab.Algorithms.NSGA3/3.3/Utility.cs

Timestamp:

08/02/20 11:39:51 (4 years ago)

Author:

dleko

Message:

#2825 Minor refactoring.

File:

• branches/2825-NSGA3/HeuristicLab.Algorithms.NSGA3/3.3/Utility.cs (modified) (2 diffs)

branches/2825-NSGA3/HeuristicLab.Algorithms.NSGA3/3.3/Utility.cs

@@ -32 +32 @@
         {
             if (n < r) throw new InvalidOperationException($"Constraint was not met: n >= r (n = {n}, r = {r})");
-            if (r < 1) throw new InvalidOperationException($"Constraint was not met: r >= 1 (r = {r})");
+            if (r < 0) throw new InvalidOperationException($"Constraint was not met: r >= 0 (r = {r})");
             if (n == r) return 1;
-            return (int)(Factorial(n) / (Factorial(r) * Factorial(n - r)));
-        }
-
-        public static long Factorial(int n)
+
+            r = Math.Max(r, n - r);
+
+            long range1 = RangeMultiplication(r + 1, n - r);
+            return (int)(range1 / Factorial(n - r));
+        }
+
+        private static long RangeMultiplication(int start, int count)
+        {
+            long s = 1;
+            return LeftFold((long a, int b) => checked(a * b), new List<int>(Enumerable.Range(start, count)), s);
+        }
+
+        private static T2 LeftFold<T1, T2>(Func<T2, T1, T2> func, List<T1> elements, T2 start)
+        {
+            var item = start;
+            foreach (var element in elements)
+                item = func(item, element);
+
+            return item;
+        }
+
+        public static long Factorial(long n)
         {
             if (n < 0 || n > 30) throw new InvalidOperationException($"Constraint for n was not met: 0 <= n <= 30 (n = {n})");
             long product = 1;
-            for (int i = 2; i <= n; i++)
+            for (long i = 2; i <= n; i++)
                 product *= i;
 
             return product;
         }
+
         public static double[][] ToJaggedArray(this DoubleMatrix m)
         {
@@ -94 +114 @@
         {
             if (referencePoints == null || !referencePoints.Any()) throw new ArgumentException($"{nameof(referencePoints)} is null or empty");
-            int nDim = referencePoints.First().NumberOfDimensions;
+            int obj = referencePoints.First().Objectives;
             int pointCount = referencePoints.Count;
-            double[,] array = new double[nDim, pointCount];
+            double[,] array = new double[obj, pointCount];
 
             for (int p = 0; p < pointCount; p++)
-                for (int d = 0; d < nDim; d++)
+                for (int d = 0; d < obj; d++)
                     array[d, p] = referencePoints[p].Values[d];