Ejemplo n.º 1
0
        //! identity instance
        public IOperator identity(int size)
        {
            TridiagonalOperator I = new TridiagonalOperator(new Vector(size - 1, 0.0),  // lower diagonal
                                                            new Vector(size, 1.0),      // diagonal
                                                            new Vector(size - 1, 0.0)); // upper diagonal

            return(I);
        }
Ejemplo n.º 2
0
        public IOperator multiply(double a, IOperator o)
        {
            TridiagonalOperator D      = o as TridiagonalOperator;
            Vector low                 = D.lowerDiagonal_ * a,
                   mid                 = D.diagonal_ * a,
                   high                = D.upperDiagonal_ * a;
            TridiagonalOperator result = new TridiagonalOperator(low, mid, high);

            return(result);
        }
Ejemplo n.º 3
0
        public IOperator subtract(IOperator A, IOperator B)
        {
            TridiagonalOperator D1 = A as TridiagonalOperator;
            TridiagonalOperator D2 = B as TridiagonalOperator;

            Vector low  = D1.lowerDiagonal_ - D2.lowerDiagonal_,
                   mid  = D1.diagonal_ - D2.diagonal_,
                   high = D1.upperDiagonal_ - D2.upperDiagonal_;
            TridiagonalOperator result = new TridiagonalOperator(low, mid, high);

            return(result);
        }
Ejemplo n.º 4
0
        public void generateOperator(double t, TransformedGrid tg, TridiagonalOperator L)
        {
            for (int i = 1; i < tg.size() - 1; i++)
            {
                double sigma  = diffusion(t, tg.grid(i));
                double nu     = drift(t, tg.grid(i));
                double r      = discount(t, tg.grid(i));
                double sigma2 = sigma * sigma;

                double pd = -(sigma2 / tg.dxm(i) - nu) / tg.dx(i);
                double pu = -(sigma2 / tg.dxp(i) + nu) / tg.dx(i);
                double pm = sigma2 / (tg.dxm(i) * tg.dxp(i)) + r;
                L.setMidRow(i, pd, pm, pu);
            }
        }
Ejemplo n.º 5
0
        // interface
        public override void applyBeforeApplying(IOperator o)
        {
            TridiagonalOperator L = o as TridiagonalOperator;

            switch (side_)
            {
            case Side.Lower:
                L.setFirstRow(-1.0, 1.0);
                break;

            case Side.Upper:
                L.setLastRow(-1.0, 1.0);
                break;

            default:
                throw new ArgumentException("unknown side for Neumann boundary condition");
            }
        }
Ejemplo n.º 6
0
        public override void applyBeforeSolving(IOperator o, Vector rhs)
        {
            TridiagonalOperator L = o as TridiagonalOperator;

            switch (side_)
            {
            case Side.Lower:
                L.setFirstRow(-1.0, 1.0);
                rhs[0] = value_;
                break;

            case Side.Upper:
                L.setLastRow(-1.0, 1.0);
                rhs[rhs.size() - 1] = value_;
                break;

            default:
                throw new ArgumentException("unknown side for Neumann boundary condition");
            }
        }
Ejemplo n.º 7
0
        public override void update()
        {
            Vector        tmp = new Vector(size_);
            List <double> dx  = new InitializedList <double>(size_ - 1),
                          S   = new InitializedList <double>(size_ - 1);

            for (int i = 0; i < size_ - 1; ++i)
            {
                dx[i] = xBegin_[i + 1] - xBegin_[i];
                S[i]  = (yBegin_[i + 1] - yBegin_[i]) / dx[i];
            }

            // first derivative approximation
            if (da_ == CubicInterpolation.DerivativeApprox.Spline)
            {
                TridiagonalOperator L = new TridiagonalOperator(size_);
                for (int i = 1; i < size_ - 1; ++i)
                {
                    L.setMidRow(i, dx[i], 2.0 * (dx[i] + dx[i - 1]), dx[i - 1]);
                    tmp[i] = 3.0 * (dx[i] * S[i - 1] + dx[i - 1] * S[i]);
                }

                // left boundary condition
                switch (leftType_)
                {
                case CubicInterpolation.BoundaryCondition.NotAKnot:
                    // ignoring end condition value
                    L.setFirstRow(dx[1] * (dx[1] + dx[0]), (dx[0] + dx[1]) * (dx[0] + dx[1]));
                    tmp[0] = S[0] * dx[1] * (2.0 * dx[1] + 3.0 * dx[0]) + S[1] * dx[0] * dx[0];
                    break;

                case CubicInterpolation.BoundaryCondition.FirstDerivative:
                    L.setFirstRow(1.0, 0.0);
                    tmp[0] = leftValue_;
                    break;

                case CubicInterpolation.BoundaryCondition.SecondDerivative:
                    L.setFirstRow(2.0, 1.0);
                    tmp[0] = 3.0 * S[0] - leftValue_ * dx[0] / 2.0;
                    break;

                case CubicInterpolation.BoundaryCondition.Periodic:
                    // ignoring end condition value
                    throw new NotImplementedException("this end condition is not implemented yet");

                case CubicInterpolation.BoundaryCondition.Lagrange:
                    L.setFirstRow(1.0, 0.0);
                    tmp[0] = cubicInterpolatingPolynomialDerivative(
                        this.xBegin_[0], this.xBegin_[1],
                        this.xBegin_[2], this.xBegin_[3],
                        this.yBegin_[0], this.yBegin_[1],
                        this.yBegin_[2], this.yBegin_[3],
                        this.xBegin_[0]);
                    break;

                default:
                    throw new ArgumentException("unknown end condition");
                }

                // right boundary condition
                switch (rightType_)
                {
                case CubicInterpolation.BoundaryCondition.NotAKnot:
                    // ignoring end condition value
                    L.setLastRow(-(dx[size_ - 2] + dx[size_ - 3]) * (dx[size_ - 2] + dx[size_ - 3]),
                                 -dx[size_ - 3] * (dx[size_ - 3] + dx[size_ - 2]));
                    tmp[size_ - 1] = -S[size_ - 3] * dx[size_ - 2] * dx[size_ - 2] -
                                     S[size_ - 2] * dx[size_ - 3] * (3.0 * dx[size_ - 2] + 2.0 * dx[size_ - 3]);
                    break;

                case CubicInterpolation.BoundaryCondition.FirstDerivative:
                    L.setLastRow(0.0, 1.0);
                    tmp[size_ - 1] = rightValue_;
                    break;

                case CubicInterpolation.BoundaryCondition.SecondDerivative:
                    L.setLastRow(1.0, 2.0);
                    tmp[size_ - 1] = 3.0 * S[size_ - 2] + rightValue_ * dx[size_ - 2] / 2.0;
                    break;

                case CubicInterpolation.BoundaryCondition.Periodic:
                    // ignoring end condition value
                    throw new NotImplementedException("this end condition is not implemented yet");

                case CubicInterpolation.BoundaryCondition.Lagrange:
                    L.setLastRow(0.0, 1.0);
                    tmp[size_ - 1] = cubicInterpolatingPolynomialDerivative(
                        this.xBegin_[size_ - 4], this.xBegin_[size_ - 3],
                        this.xBegin_[size_ - 2], this.xBegin_[size_ - 1],
                        this.yBegin_[size_ - 4], this.yBegin_[size_ - 3],
                        this.yBegin_[size_ - 2], this.yBegin_[size_ - 1],
                        this.xBegin_[size_ - 1]);
                    break;

                default:
                    throw new ArgumentException("unknown end condition");
                }

                // solve the system
                tmp = L.solveFor(tmp);
            }
            else if (da_ == CubicInterpolation.DerivativeApprox.SplineOM1)
            {
                Matrix T_ = new Matrix(size_ - 2, size_, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    T_[i, i]     = dx[i] / 6.0;
                    T_[i, i + 1] = (dx[i + 1] + dx[i]) / 3.0;
                    T_[i, i + 2] = dx[i + 1] / 6.0;
                }
                Matrix S_ = new Matrix(size_ - 2, size_, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    S_[i, i]     = 1.0 / dx[i];
                    S_[i, i + 1] = -(1.0 / dx[i + 1] + 1.0 / dx[i]);
                    S_[i, i + 2] = 1.0 / dx[i + 1];
                }
                Matrix Up_ = new Matrix(size_, 2, 0.0);
                Up_[0, 0]         = 1;
                Up_[size_ - 1, 1] = 1;
                Matrix Us_ = new Matrix(size_, size_ - 2, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    Us_[i + 1, i] = 1;
                }
                Matrix Z_ = Us_ * Matrix.inverse(T_ * Us_);
                Matrix I_ = new Matrix(size_, size_, 0.0);
                for (int i = 0; i < size_; ++i)
                {
                    I_[i, i] = 1;
                }
                Matrix V_ = (I_ - Z_ * T_) * Up_;
                Matrix W_ = Z_ * S_;
                Matrix Q_ = new Matrix(size_, size_, 0.0);
                Q_[0, 0] = 1.0 / (size_ - 1) * dx[0] * dx[0] * dx[0];
                Q_[0, 1] = 7.0 / 8 * 1.0 / (size_ - 1) * dx[0] * dx[0] * dx[0];
                for (int i = 1; i < size_ - 1; ++i)
                {
                    Q_[i, i - 1] = 7.0 / 8 * 1.0 / (size_ - 1) * dx[i - 1] * dx[i - 1] * dx[i - 1];
                    Q_[i, i]     = 1.0 / (size_ - 1) * dx[i] * dx[i] * dx[i] + 1.0 / (size_ - 1) * dx[i - 1] * dx[i - 1] * dx[i - 1];
                    Q_[i, i + 1] = 7.0 / 8 * 1.0 / (size_ - 1) * dx[i] * dx[i] * dx[i];
                }
                Q_[size_ - 1, size_ - 2] = 7.0 / 8 * 1.0 / (size_ - 1) * dx[size_ - 2] * dx[size_ - 2] * dx[size_ - 2];
                Q_[size_ - 1, size_ - 1] = 1.0 / (size_ - 1) * dx[size_ - 2] * dx[size_ - 2] * dx[size_ - 2];
                Matrix J_ = (I_ - V_ * Matrix.inverse(Matrix.transpose(V_) * Q_ * V_) * Matrix.transpose(V_) * Q_) * W_;
                Vector Y_ = new Vector(size_);
                for (int i = 0; i < size_; ++i)
                {
                    Y_[i] = this.yBegin_[i];
                }
                Vector D_ = J_ * Y_;
                for (int i = 0; i < size_ - 1; ++i)
                {
                    tmp[i] = (Y_[i + 1] - Y_[i]) / dx[i] - (2.0 * D_[i] + D_[i + 1]) * dx[i] / 6.0;
                }
                tmp[size_ - 1] = tmp[size_ - 2] + D_[size_ - 2] * dx[size_ - 2] + (D_[size_ - 1] - D_[size_ - 2]) * dx[size_ - 2] / 2.0;
            }
            else if (da_ == CubicInterpolation.DerivativeApprox.SplineOM2)
            {
                Matrix T_ = new Matrix(size_ - 2, size_, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    T_[i, i]     = dx[i] / 6.0;
                    T_[i, i + 1] = (dx[i] + dx[i + 1]) / 3.0;
                    T_[i, i + 2] = dx[i + 1] / 6.0;
                }
                Matrix S_ = new Matrix(size_ - 2, size_, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    S_[i, i]     = 1.0 / dx[i];
                    S_[i, i + 1] = -(1.0 / dx[i + 1] + 1.0 / dx[i]);
                    S_[i, i + 2] = 1.0 / dx[i + 1];
                }
                Matrix Up_ = new Matrix(size_, 2, 0.0);
                Up_[0, 0]         = 1;
                Up_[size_ - 1, 1] = 1;
                Matrix Us_ = new Matrix(size_, size_ - 2, 0.0);
                for (int i = 0; i < size_ - 2; ++i)
                {
                    Us_[i + 1, i] = 1;
                }
                Matrix Z_ = Us_ * Matrix.inverse(T_ * Us_);
                Matrix I_ = new Matrix(size_, size_, 0.0);
                for (int i = 0; i < size_; ++i)
                {
                    I_[i, i] = 1;
                }
                Matrix V_ = (I_ - Z_ * T_) * Up_;
                Matrix W_ = Z_ * S_;
                Matrix Q_ = new Matrix(size_, size_, 0.0);
                Q_[0, 0] = 1.0 / (size_ - 1) * dx[0];
                Q_[0, 1] = 1.0 / 2 * 1.0 / (size_ - 1) * dx[0];
                for (int i = 1; i < size_ - 1; ++i)
                {
                    Q_[i, i - 1] = 1.0 / 2 * 1.0 / (size_ - 1) * dx[i - 1];
                    Q_[i, i]     = 1.0 / (size_ - 1) * dx[i] + 1.0 / (size_ - 1) * dx[i - 1];
                    Q_[i, i + 1] = 1.0 / 2 * 1.0 / (size_ - 1) * dx[i];
                }
                Q_[size_ - 1, size_ - 2] = 1.0 / 2 * 1.0 / (size_ - 1) * dx[size_ - 2];
                Q_[size_ - 1, size_ - 1] = 1.0 / (size_ - 1) * dx[size_ - 2];
                Matrix J_ = (I_ - V_ * Matrix.inverse(Matrix.transpose(V_) * Q_ * V_) * Matrix.transpose(V_) * Q_) * W_;
                Vector Y_ = new Vector(size_);
                for (int i = 0; i < size_; ++i)
                {
                    Y_[i] = this.yBegin_[i];
                }
                Vector D_ = J_ * Y_;
                for (int i = 0; i < size_ - 1; ++i)
                {
                    tmp[i] = (Y_[i + 1] - Y_[i]) / dx[i] - (2.0 * D_[i] + D_[i + 1]) * dx[i] / 6.0;
                }
                tmp[size_ - 1] = tmp[size_ - 2] + D_[size_ - 2] * dx[size_ - 2] + (D_[size_ - 1] - D_[size_ - 2]) * dx[size_ - 2] / 2.0;
            }
            else
            {
                // local schemes
                if (size_ == 2)
                {
                    tmp[0] = tmp[1] = S[0];
                }
                else
                {
                    switch (da_)
                    {
                    case CubicInterpolation.DerivativeApprox.FourthOrder:
                        throw new NotImplementedException("FourthOrder not implemented yet");

                    case CubicInterpolation.DerivativeApprox.Parabolic:
                        // intermediate points
                        for (int i = 1; i < size_ - 1; ++i)
                        {
                            tmp[i] = (dx[i - 1] * S[i] + dx[i] * S[i - 1]) / (dx[i] + dx[i - 1]);
                        }
                        // end points
                        tmp[0]         = ((2.0 * dx[0] + dx[1]) * S[0] - dx[0] * S[1]) / (dx[0] + dx[1]);
                        tmp[size_ - 1] = ((2.0 * dx[size_ - 2] + dx[size_ - 3]) * S[size_ - 2] -
                                          dx[size_ - 2] * S[size_ - 3]) / (dx[size_ - 2] + dx[size_ - 3]);
                        break;

                    case CubicInterpolation.DerivativeApprox.FritschButland:
                        // intermediate points
                        for (int i = 1; i < size_ - 1; ++i)
                        {
                            double Smin = Math.Min(S[i - 1], S[i]);
                            double Smax = Math.Max(S[i - 1], S[i]);
                            tmp[i] = 3.0 * Smin * Smax / (Smax + 2.0 * Smin);
                        }
                        // end points
                        tmp[0]         = ((2.0 * dx[0] + dx[1]) * S[0] - dx[0] * S[1]) / (dx[0] + dx[1]);
                        tmp[size_ - 1] = ((2.0 * dx[size_ - 2] + dx[size_ - 3]) * S[size_ - 2] -
                                          dx[size_ - 2] * S[size_ - 3]) / (dx[size_ - 2] + dx[size_ - 3]);
                        break;

                    case CubicInterpolation.DerivativeApprox.Akima:
                        tmp[0] = (Math.Abs(S[1] - S[0]) * 2 * S[0] * S[1] +
                                  Math.Abs(2 * S[0] * S[1] - 4 * S[0] * S[0] * S[1]) * S[0]) /
                                 (Math.Abs(S[1] - S[0]) + Math.Abs(2 * S[0] * S[1] - 4 * S[0] * S[0] * S[1]));
                        tmp[1] = (Math.Abs(S[2] - S[1]) * S[0] + Math.Abs(S[0] - 2 * S[0] * S[1]) * S[1]) /
                                 (Math.Abs(S[2] - S[1]) + Math.Abs(S[0] - 2 * S[0] * S[1]));
                        for (int i = 2; i < size_ - 2; ++i)
                        {
                            if ((S[i - 2].IsEqual(S[i - 1])) && (S[i].IsNotEqual(S[i + 1])))
                            {
                                tmp[i] = S[i - 1];
                            }
                            else if ((S[i - 2].IsNotEqual(S[i - 1])) && (S[i].IsEqual(S[i + 1])))
                            {
                                tmp[i] = S[i];
                            }
                            else if (S[i].IsEqual(S[i - 1]))
                            {
                                tmp[i] = S[i];
                            }
                            else if ((S[i - 2].IsEqual(S[i - 1])) && (S[i - 1].IsNotEqual(S[i])) && (S[i].IsEqual(S[i + 1])))
                            {
                                tmp[i] = (S[i - 1] + S[i]) / 2.0;
                            }
                            else
                            {
                                tmp[i] = (Math.Abs(S[i + 1] - S[i]) * S[i - 1] + Math.Abs(S[i - 1] - S[i - 2]) * S[i]) /
                                         (Math.Abs(S[i + 1] - S[i]) + Math.Abs(S[i - 1] - S[i - 2]));
                            }
                        }
                        tmp[size_ - 2] = (Math.Abs(2 * S[size_ - 2] * S[size_ - 3] - S[size_ - 2]) * S[size_ - 3] +
                                          Math.Abs(S[size_ - 3] - S[size_ - 4]) * S[size_ - 2]) /
                                         (Math.Abs(2 * S[size_ - 2] * S[size_ - 3] - S[size_ - 2]) +
                                          Math.Abs(S[size_ - 3] - S[size_ - 4]));
                        tmp[size_ - 1] =
                            (Math.Abs(4 * S[size_ - 2] * S[size_ - 2] * S[size_ - 3] - 2 * S[size_ - 2] * S[size_ - 3]) *
                             S[size_ - 2] + Math.Abs(S[size_ - 2] - S[size_ - 3]) * 2 * S[size_ - 2] * S[size_ - 3]) /
                            (Math.Abs(4 * S[size_ - 2] * S[size_ - 2] * S[size_ - 3] - 2 * S[size_ - 2] * S[size_ - 3]) +
                             Math.Abs(S[size_ - 2] - S[size_ - 3]));
                        break;

                    case CubicInterpolation.DerivativeApprox.Kruger:
                        // intermediate points
                        for (int i = 1; i < size_ - 1; ++i)
                        {
                            if (S[i - 1] * S[i] < 0.0)
                            {
                                // slope changes sign at point
                                tmp[i] = 0.0;
                            }
                            else
                            {
                                // slope will be between the slopes of the adjacent
                                // straight lines and should approach zero if the
                                // slope of either line approaches zero
                                tmp[i] = 2.0 / (1.0 / S[i - 1] + 1.0 / S[i]);
                            }
                        }
                        // end points
                        tmp[0]         = (3.0 * S[0] - tmp[1]) / 2.0;
                        tmp[size_ - 1] = (3.0 * S[size_ - 2] - tmp[size_ - 2]) / 2.0;
                        break;

                    case CubicInterpolation.DerivativeApprox.Harmonic:
                        // intermediate points
                        for (int i = 1; i < size_ - 1; ++i)
                        {
                            double w1 = 2 * dx[i] + dx[i - 1];
                            double w2 = dx[i] + 2 * dx[i - 1];
                            if (S[i - 1] * S[i] <= 0.0)
                            {
                                // slope changes sign at point
                                tmp[i] = 0.0;
                            }
                            else
                            {
                                // weighted harmonic mean of S[i] and S[i-1] if they
                                // have the same sign; otherwise 0
                                tmp[i] = (w1 + w2) / (w1 / S[i - 1] + w2 / S[i]);
                            }
                        }
                        // end points [0]
                        tmp[0] = ((2 * dx[0] + dx[1]) * S[0] - dx[0] * S[1]) / (dx[1] + dx[0]);
                        if (tmp[0] * S[0] < 0.0)
                        {
                            tmp[0] = 0;
                        }
                        else if (S[0] * S[1] < 0)
                        {
                            if (Math.Abs(tmp[0]) > Math.Abs(3 * S[0]))
                            {
                                tmp[0] = 3 * S[0];
                            }
                        }
                        // end points [n-1]
                        tmp[size_ - 1] = ((2 * dx[size_ - 2] + dx[size_ - 3]) * S[size_ - 2] - dx[size_ - 2] * S[size_ - 3]) / (dx[size_ - 3] + dx[size_ - 2]);
                        if (tmp[size_ - 1] * S[size_ - 2] < 0.0)
                        {
                            tmp[size_ - 1] = 0;
                        }
                        else if (S[size_ - 2] * S[size_ - 3] < 0)
                        {
                            if (Math.Abs(tmp[size_ - 1]) > Math.Abs(3 * S[size_ - 2]))
                            {
                                tmp[size_ - 1] = 3 * S[size_ - 2];
                            }
                        }
                        break;

                    default:
                        throw new ArgumentException("unknown scheme");
                    }
                }
            }

            monotonicityAdjustments_.Erase();

            // Hyman monotonicity constrained filter
            if (monotonic_)
            {
                double correction;
                double pm, pu, pd, M;
                for (int i = 0; i < size_; ++i)
                {
                    if (i == 0)
                    {
                        if (tmp[i] * S[0] > 0.0)
                        {
                            correction = tmp[i] / Math.Abs(tmp[i]) *
                                         Math.Min(Math.Abs(tmp[i]),
                                                  Math.Abs(3.0 * S[0]));
                        }
                        else
                        {
                            correction = 0.0;
                        }
                        if (correction.IsNotEqual(tmp[i]))
                        {
                            tmp[i] = correction;
                            monotonicityAdjustments_[i] = true;
                        }
                    }
                    else if (i == size_ - 1)
                    {
                        if (tmp[i] * S[size_ - 2] > 0.0)
                        {
                            correction = tmp[i] / Math.Abs(tmp[i]) *
                                         Math.Min(Math.Abs(tmp[i]), Math.Abs(3.0 * S[size_ - 2]));
                        }
                        else
                        {
                            correction = 0.0;
                        }
                        if (correction.IsNotEqual(tmp[i]))
                        {
                            tmp[i] = correction;
                            monotonicityAdjustments_[i] = true;
                        }
                    }
                    else
                    {
                        pm = (S[i - 1] * dx[i] + S[i] * dx[i - 1]) /
                             (dx[i - 1] + dx[i]);
                        M = 3.0 * Math.Min(Math.Min(Math.Abs(S[i - 1]), Math.Abs(S[i])),
                                           Math.Abs(pm));
                        if (i > 1)
                        {
                            if ((S[i - 1] - S[i - 2]) * (S[i] - S[i - 1]) > 0.0)
                            {
                                pd = (S[i - 1] * (2.0 * dx[i - 1] + dx[i - 2])
                                      - S[i - 2] * dx[i - 1]) /
                                     (dx[i - 2] + dx[i - 1]);
                                if (pm * pd > 0.0 && pm * (S[i - 1] - S[i - 2]) > 0.0)
                                {
                                    M = Math.Max(M, 1.5 * Math.Min(
                                                     Math.Abs(pm), Math.Abs(pd)));
                                }
                            }
                        }
                        if (i < size_ - 2)
                        {
                            if ((S[i] - S[i - 1]) * (S[i + 1] - S[i]) > 0.0)
                            {
                                pu = (S[i] * (2.0 * dx[i] + dx[i + 1]) - S[i + 1] * dx[i]) /
                                     (dx[i] + dx[i + 1]);
                                if (pm * pu > 0.0 && -pm * (S[i] - S[i - 1]) > 0.0)
                                {
                                    M = Math.Max(M, 1.5 * Math.Min(
                                                     Math.Abs(pm), Math.Abs(pu)));
                                }
                            }
                        }
                        if (tmp[i] * pm > 0.0)
                        {
                            correction = tmp[i] / Math.Abs(tmp[i]) *
                                         Math.Min(Math.Abs(tmp[i]), M);
                        }
                        else
                        {
                            correction = 0.0;
                        }
                        if (correction.IsNotEqual(tmp[i]))
                        {
                            tmp[i] = correction;
                            monotonicityAdjustments_[i] = true;
                        }
                    }
                }
            }

            // cubic coefficients
            for (int i = 0; i < size_ - 1; ++i)
            {
                a_[i] = tmp[i];
                b_[i] = (3.0 * S[i] - tmp[i + 1] - 2.0 * tmp[i]) / dx[i];
                c_[i] = (tmp[i + 1] + tmp[i] - 2.0 * S[i]) / (dx[i] * dx[i]);
            }

            primitiveConst_[0] = 0.0;
            for (int i = 1; i < size_ - 1; ++i)
            {
                primitiveConst_[i] = primitiveConst_[i - 1]
                                     + dx[i - 1] *
                                     (yBegin_[i - 1] + dx[i - 1] *
                                      (a_[i - 1] / 2.0 + dx[i - 1] *
                                       (b_[i - 1] / 3.0 + dx[i - 1] * c_[i - 1] / 4.0)));
            }
        }
Ejemplo n.º 8
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 protected void initializeOperator()
 {
     finiteDifferenceOperator_ = OperatorFactory.getOperator(process_, intrinsicValues_.grid(),
                                                             getResidualTime(), timeDependent_);
 }
Ejemplo n.º 9
0
        public override void calculate(IPricingEngineResults r)
        {
            OneAssetOption.Results results = r as OneAssetOption.Results;
            setGridLimits();
            initializeInitialCondition();
            initializeOperator();
            initializeBoundaryConditions();
            initializeStepCondition();

            List <IOperator>          operatorSet  = new List <IOperator>();
            List <Vector>             arraySet     = new List <Vector>();
            BoundaryConditionSet      bcSet        = new BoundaryConditionSet();
            StepConditionSet <Vector> conditionSet = new StepConditionSet <Vector>();

            prices_ = (SampledCurve)intrinsicValues_.Clone();

            controlPrices_   = (SampledCurve)intrinsicValues_.Clone();
            controlOperator_ = (TridiagonalOperator)finiteDifferenceOperator_.Clone();
            controlBCs_[0]   = BCs_[0];
            controlBCs_[1]   = BCs_[1];

            operatorSet.Add(finiteDifferenceOperator_);
            operatorSet.Add(controlOperator_);

            arraySet.Add(prices_.values());
            arraySet.Add(controlPrices_.values());

            bcSet.Add(BCs_);
            bcSet.Add(controlBCs_);

            conditionSet.Add(stepCondition_);
            conditionSet.Add(new NullCondition <Vector>());

            var model = new FiniteDifferenceModel <ParallelEvolver <CrankNicolson <TridiagonalOperator> > >(operatorSet, bcSet);

            object temp = arraySet;

            model.rollback(ref temp, getResidualTime(), 0.0, timeSteps_, conditionSet);
            arraySet = (List <Vector>)temp;

            prices_.setValues(arraySet[0]);
            controlPrices_.setValues(arraySet[1]);

            StrikedTypePayoff striked_payoff = payoff_ as StrikedTypePayoff;

            Utils.QL_REQUIRE(striked_payoff != null, () => "non-striked payoff given");

            double variance         = process_.blackVolatility().link.blackVariance(exerciseDate_, striked_payoff.strike());
            double dividendDiscount = process_.dividendYield().link.discount(exerciseDate_);
            double riskFreeDiscount = process_.riskFreeRate().link.discount(exerciseDate_);
            double spot             = process_.stateVariable().link.value();
            double forwardPrice     = spot * dividendDiscount / riskFreeDiscount;

            BlackCalculator black = new BlackCalculator(striked_payoff, forwardPrice, Math.Sqrt(variance), riskFreeDiscount);

            results.value = prices_.valueAtCenter()
                            - controlPrices_.valueAtCenter()
                            + black.value();
            results.delta = prices_.firstDerivativeAtCenter()
                            - controlPrices_.firstDerivativeAtCenter()
                            + black.delta(spot);
            results.gamma = prices_.secondDerivativeAtCenter()
                            - controlPrices_.secondDerivativeAtCenter()
                            + black.gamma(spot);
            results.additionalResults["priceCurve"] = prices_;
        }