CrossProduct.cs

using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects.VectorSpaces;
 
namespace Waher.Script.Operators.Vectors
{
    public class CrossProduct : BinaryVectorOperator
    {
        public CrossProduct(ScriptNode Left, ScriptNode Right, int Start, int Length, Expression Expression)
            : base(Left, Right, Start, Length, Expression)
        {
        }
 
        public override IElement EvaluateVector(IVector Left, IVector Right, Variables Variables)
        {
            if (Left.Dimension != 3 || Right.Dimension != 3)
                throw new ScriptRuntimeException("Cross product works on vectors of dimesion 3.", this);
 
            if (Left is DoubleVector dv1 && Right is DoubleVector dv2)
            {
                double[] d1 = dv1.Values;
                double[] d2 = dv2.Values;
 
                return new DoubleVector(new double[] { d1[1] * d2[2] - d1[2] * d2[1], d1[2] * d2[0] - d1[0] * d2[2], d1[0] * d2[1] - d1[1] * d2[0] });
            }
 
            IElement[] v1 = new IElement[3];
            Left.VectorElements.CopyTo(v1, 0);
 
            IElement[] v2 = new IElement[3];
            Right.VectorElements.CopyTo(v2, 0);
 
            return VectorDefinition.Encapsulate(new IElement[]
            {
                Arithmetics.Subtract.EvaluateSubtraction(
                    Arithmetics.Multiply.EvaluateMultiplication(v1[1], v2[2], this),
                    Arithmetics.Multiply.EvaluateMultiplication(v1[2], v2[1], this), this),
                Arithmetics.Subtract.EvaluateSubtraction(
                    Arithmetics.Multiply.EvaluateMultiplication(v1[2], v2[0], this), 
                    Arithmetics.Multiply.EvaluateMultiplication(v1[0], v2[2], this), this),
                Arithmetics.Subtract.EvaluateSubtraction(
                    Arithmetics.Multiply.EvaluateMultiplication(v1[0], v2[1], this), 
                    Arithmetics.Multiply.EvaluateMultiplication(v1[1], v2[0], this), this)
            }, false, this);
        }
 
    }
}