public static void CheckParallel(this Arrow first, Arrow second)
{
if (first.Dot(second) <= 0)
{
throw new ArgumentException("Arrows must point in the same general direction.");
}
}
public static void CheckPerpendicular(this Arrow first, Arrow second)
{
if (first.Dot(second) != 0)
{
throw new ArgumentException("Arrows must be perpendicular.");
}
}
public static IAuto <Arrow> Rotate(this Arrow axis)
{
axis.CheckUnit();
return(new Auto <Arrow>(
morphF: arrow =>
{
var projection = axis.Scale((Sign)axis.Dot(arrow));
return axis.Cross(arrow).Add(projection);
}));
}
public static int Magnitude(this Arrow arrow)
{
return(arrow.Dot(arrow));
}
