DivideElementWise.cs

using System;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Operators.Arithmetics
{
    public class DivideElementWise : BinaryElementWiseOperator, IDifferentiable
    {
        public DivideElementWise(ScriptNode Left, ScriptNode Right, int Start, int Length, Expression Expression)
            : base(Left, Right, Start, Length, Expression)
        {
        }
 
        public override IElement EvaluateScalar(IElement Left, IElement Right, Variables Variables)
        {
            if (Left.AssociatedObjectValue is double DL && Right.AssociatedObjectValue is double DR)
                return new DoubleNumber(DL / DR);
            else
                return Divide.EvaluateDivision(Left, Right, this);
        }
 
        public ScriptNode Differentiate(string VariableName, Variables Variables)
        {
            if (this.left is IDifferentiable Left &&
                this.right is IDifferentiable Right)
            {
                int Start = this.Start;
                int Len = this.Length;
                Expression Expression = this.Expression;
 
                return new DivideElementWise(
                    new Subtract(
                        new MultiplyElementWise(
                            Left.Differentiate(VariableName, Variables),
                            this.right,
                            Start, Len, Expression),
                        new MultiplyElementWise(
                            this.left,
                            Right.Differentiate(VariableName, Variables),
                            Start, Len, Expression),
                        Start, Len, Expression),
                    new MultiplyElementWise(
                        this.right, this.right, Start, Len, Expression),
                    Start, Len, Expression);
            }
            else
                throw new ScriptRuntimeException("Factors not differentiable.", this);
        }
 
    }
}