Ejemplo n.º 1
0
        public static IList <double> QuadraticDRootsPoMax(double a, double b, double c, double epsilon = Epsilon)
        {
            // If a is 0 the polynomial is linear.
            if (a is 0d)
            {
                return(LinearRootsTests.LinearRoots(b, c, epsilon));
            }

            var d = a - (2d * b) + c;

            if (d != 0)
            {
                // The 4 is missing?
                var m1 = -Sqrt((b * b) - (a * c));
                var m2 = -a + b;
                var v1 = -(m1 + m2) / d;
                var v2 = -(-m1 + m2) / d;
                return(new List <double> {
                    v1, v2
                });
            }
            else if (b != c && d == 0d)
            {
                return(new List <double> {
                    ((2d * b) - c) / (2d * (b - c))
                });
            }

            return(new List <double>());
        }
Ejemplo n.º 2
0
        public static IList <double> QuadraticEquation(double a, double b, double c, double epsilon = Epsilon)
        {
            // If a is 0 the polynomial is linear.
            if (a is 0d)
            {
                return(LinearRootsTests.LinearRoots(b, c, epsilon));
            }

            return(new List <double> {
                (-b - Sqrt((b * b) - (4d * a * c))) / (2d * a),
                (-b + Sqrt((b * b) - (4d * a * c))) / (2d * a),
            });
        }
Ejemplo n.º 3
0
        public static IList <double> QuadraticRootsKevinLinDev(double a, double b, double c, double epsilon = Epsilon)
        {
            // If a is 0 the polynomial is linear.
            if (a is 0d)
            {
                return(LinearRootsTests.LinearRoots(b, c, epsilon));
            }

            var b_ = b / a;
            var c_ = c / a;

            // Polynomial discriminant.
            var discriminant = (b_ * b_) - (4d * c_);

            if (Abs(discriminant) <= epsilon)
            {
                discriminant = 0d;
            }

            // ToDo: May need to switch from a hash set to a list for scan-beams.
            var results = new HashSet <double>();

            if (discriminant > 0d)
            {
                // Complex or duplicate roots.
                var e = Sqrt(discriminant);
                results.Add(OneHalf * (-b_ + e));
                results.Add(OneHalf * (-b_ - e));
            }
            else if (discriminant == 0)
            {
                // There should actually be two roots with same value, but we will only return one.
                results.Add(OneHalf * -b_);
            }
            else if (discriminant < 0d)
            {
                // Complex or duplicate roots.
                var e = -Sqrt(-discriminant);
                results.Add(OneHalf * (-b_ + e));
                results.Add(OneHalf * (-b_ - e));
            }

            return(results.ToList());
        }