matlab中ode45函数编写.docVIP

function varargout = ode45(ode,tspan,y0,options,varargin) %ODE45 Solve non-stiff differential equations, medium order method. % [TOUT,YOUT] = ODE45(ODEFUN,TSPAN,Y0) with TSPAN = [T0 TFINAL] integrates % the system of differential equations y = f(t,y) from time T0 to TFINAL % with initial conditions Y0. ODEFUN is a function handle. For a scalar T % and a vector Y, ODEFUN(T,Y) must return a column vector corresponding % to f(t,y). Each row in the solution array YOUT corresponds to a time % returned in the column vector TOUT. To obtain solutions at specific % times T0,T1,...,TFINAL (all increasing or all decreasing), use TSPAN = % [T0 T1 ... TFINAL]. % % [TOUT,YOUT] = ODE45(ODEFUN,TSPAN,Y0,OPTIONS) solves as above with default % integration properties replaced by values in OPTIONS, an argument created % with the ODESET function. See ODESET for details. Commonly used options % are scalar relative error tolerance RelTol (1e-3 by default) and vector % of absolute error tolerances AbsTol (all components 1e-6 by default). % If certain components of the solution must be non-negative, use % ODESET to set the NonNegative property to the indices of these % components. % % ODE45 can solve problems M(t,y)*y = f(t,y) with mass matrix M that is % nonsingular. Use ODESET to set the Mass property to a function handle % MASS if MASS(T,Y) returns the value of the mass matrix. If the mass matrix % is constant, the matrix can be used as the value of the Mass option. If % the mass matrix does not depend on the state variable Y and the function % MASS is to be called with one input argument T, set MStateDependence to % none. ODE15S and ODE23T can solve problems with singular mass matrices. % % [TOUT,YOUT,TE,YE,IE] = ODE45(ODEFUN,TSPAN,Y0,OPTIONS) with the Events % property in OPTIONS set to a function handle EVENTS, solves as above % while also finding where functions of (T,Y), called event functions, % are zer