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C++ API

Function File: [] = ode45 (@fun, slot, init, [opt], [par1, par2, ...])

Command: [sol] = ode45 (@fun, slot, init, [opt], [par1, par2, ...])

Command: [t, y, [xe, ye, ie]] = ode45 (@fun, slot, init, [opt], [par1, par2, ...])

This function file can be used to solve a set of non–stiff ordinary differential equations (non–stiff ODEs) or non–stiff differential algebraic equations (non–stiff DAEs) with the well known explicit Runge–Kutta method of order (4,5).

If this function is called with no return argument then plot the solution over time in a figure window while solving the set of ODEs that are defined in a function and specified by the function handle @fun. The second input argument slot is a double vector that defines the time slot, init is a double vector that defines the initial values of the states, opt can optionally be a structure array that keeps the options created with the command odeset and par1, par2, ... can optionally be other input arguments of any type that have to be passed to the function defined by @fun.

If this function is called with one return argument then return the solution sol of type structure array after solving the set of ODEs. The solution sol has the fields x of type double column vector for the steps chosen by the solver, y of type double column vector for the solutions at each time step of x, solver of type string for the solver name and optionally the extended time stamp information xe, the extended solution information ye and the extended index information ie all of type double column vector that keep the informations of the event function if an event function handle is set in the option argument opt.

If this function is called with more than one return argument then return the time stamps t, the solution values y and optionally the extended time stamp information xe, the extended solution information ye and the extended index information ie all of type double column vector.

For example, solve an anonymous implementation of the Van der Pol equation

          fvdb = @(vt,vy) [vy(2); (1 - vy(1)^2) * vy(2) - vy(1)];
          
          vopt = odeset ("RelTol", 1e-3, "AbsTol", 1e-3, \
                   "NormControl", "on", "OutputFcn", @odeplot);
          ode45 (fvdb, [0 20], [2 0], vopt);

See also: odepkg

Package: odepkg