AverageEvaluator.cs

using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
using Waher.Script.Objects;
using Waher.Script.Operators.Arithmetics;
 
namespace Waher.Script.Functions.Vectors
{
    public class AverageEvaluator : UnaryIterativeEvaluator
    {
        private IElement sum = null;
        private double doubleSum = 0;
        private bool isDouble = true;
        private long count = 0;
 
        public AverageEvaluator(Average Node)
            : base(Node.Argument)
        {
        }
 
        public override void RestartEvaluator()
        {
            this.sum = null;
            this.count = 0;
            this.doubleSum = 0;
            this.isDouble = true;
        }
 
        public override void AggregateElement(IElement Element)
        {
            if (this.isDouble && Element is DoubleNumber D)
                this.doubleSum += D.Value;
            else if (this.sum is null)
            {
                this.isDouble = false;
 
                if (this.count == 0)
                    this.sum = Element;
                else
                    this.sum = Add.EvaluateAddition(new DoubleNumber(this.doubleSum), Element, this.Node);
            }
            else
                this.sum = Add.EvaluateAddition(this.sum, Element, this.Node);
 
            this.count++;
        }
 
        public override IElement GetAggregatedResult()
        {
            if (this.count == 0)
                return ObjectValue.Null;
            else if (this.isDouble)
                return new DoubleNumber(this.doubleSum / this.count);
            else if (this.count == 1)
                return this.sum;
            else
                return Divide.EvaluateDivision(this.sum, new DoubleNumber(this.count), this.Node);
        }
    }
}