Maths.cs

using System;
using System.Collections.Generic;
 
namespace MPewsey.Common.Mathematics
{
    public static class Maths
    {
        public static double[] CumSum(IList<double> values)
        {
            if (values.Count == 0)
                return Array.Empty<double>();
 
            double total = 0;
            var result = new double[values.Count];
 
            for (int i = 0; i < values.Count; i++)
            {
                total += values[i];
                result[i] = total;
            }
 
            return result;
        }
 
        public static void CumSum(IList<double> values, List<double> result)
        {
            result.Clear();
            double total = 0;
 
            for (int i = 0; i < values.Count; i++)
            {
                total += values[i];
                result.Add(total);
            }
        }
 
        public static double[] CumSum(IList<float> values)
        {
            if (values.Count == 0)
                return Array.Empty<double>();
 
            double total = 0;
            var result = new double[values.Count];
 
            for (int i = 0; i < values.Count; i++)
            {
                total += values[i];
                result[i] = total;
            }
 
            return result;
        }
 
        public static void CumSum(IList<float> values, List<double> result)
        {
            result.Clear();
            double total = 0;
 
            for (int i = 0; i < values.Count; i++)
            {
                total += values[i];
                result.Add(total);
            }
        }
 
        public static double[] Softmax(IList<double> values)
        {
            if (values.Count == 0)
                return Array.Empty<double>();
 
            double total = 0;
            var softmax = new double[values.Count];
 
            for (int i = 0; i < softmax.Length; i++)
            {
                var value = Math.Exp(values[i]);
                total += value;
                softmax[i] = value;
            }
 
            if (total > 0)
            {
                for (int i = 0; i < softmax.Length; i++)
                {
                    softmax[i] /= total;
                }
            }
 
            return softmax;
        }
 
        public static double[] Softmax(IList<float> values)
        {
            if (values.Count == 0)
                return Array.Empty<double>();
 
            double total = 0;
            var softmax = new double[values.Count];
 
            for (int i = 0; i < softmax.Length; i++)
            {
                var value = Math.Exp(values[i]);
                total += value;
                softmax[i] = value;
            }
 
            if (total > 0)
            {
                for (int i = 0; i < softmax.Length; i++)
                {
                    softmax[i] /= total;
                }
            }
 
            return softmax;
        }
 
        public static int MaxIndex(IList<float> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var maxValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value > maxValue)
                {
                    index = i;
                    maxValue = value;
                }
            }
 
            return index;
        }
 
        public static int MaxIndex(IList<double> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var maxValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value > maxValue)
                {
                    index = i;
                    maxValue = value;
                }
            }
 
            return index;
        }
 
        public static int MaxIndex(IList<int> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var maxValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value > maxValue)
                {
                    index = i;
                    maxValue = value;
                }
            }
 
            return index;
        }
 
        public static int MinIndex(IList<float> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var minValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value < minValue)
                {
                    index = i;
                    minValue = value;
                }
            }
 
            return index;
        }
 
        public static int MinIndex(IList<double> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var minValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value < minValue)
                {
                    index = i;
                    minValue = value;
                }
            }
 
            return index;
        }
 
        public static int MinIndex(IList<int> values)
        {
            if (values.Count == 0)
                return -1;
 
            var index = 0;
            var minValue = values[0];
 
            for (int i = 1; i < values.Count; i++)
            {
                var value = values[i];
 
                if (value < minValue)
                {
                    index = i;
                    minValue = value;
                }
            }
 
            return index;
        }
 
        public static double Clamp01(double t)
        {
            if (t < 0)
                return 0;
            if (t > 1)
                return 1;
            return t;
        }
 
        public static double Lerp(double a, double b, double t)
        {
            return LerpUnclamped(a, b, Clamp01(t));
        }
 
        public static double LerpUnclamped(double a, double b, double t)
        {
            return a * (1 - t) + b * t;
        }
    }
}