?
Численное решение уравнений Блэка–Шоулза и конвекции-диффузии с определением положения свободной границы
Boundary value problems for the Black–Scholes partial differential equation, which describes the value of a financial instrument, may contain a free boundary condition if the financial instrument allows for early exercise. This article considers free boundary value problems for the Black–Scholes equation and the convection diffusion equation. For the convection diffusion equation, a finite difference scheme is presented, which is a generalization of a known second-order accurate scheme on fixed grids, and an algorithm for determining the position of the free boundary is also proposed. For the Black–Scholes equation, which is similar to but more complex than the convection diffusion equation, a new numerical solution method is proposed. This method involves, on one hand, a modification of the finite difference scheme used for the convection diffusion equation and, on the other hand, elements of the Smoothed Particle Hydrodynamics (SPH) method. The proposed method allows for finding both the solution and the free boundary, ensuring high accuracy. Numerical experiments confirming the effectiveness of the proposed algorithms are conducted, and a comparison with known numerical methods for solving these problems is provided.