`odextend`

Extends the solution of an ODE initial value problem to a later time.

Category: Mathematics > Numerical Integration and Differential Equations

Syntax

solext = odextend(sol, odefun, tfinal)

Continues the integration of sol up to tfinal.

solext = odextend(sol, odefun, tfinal, yinit)

Restarts from the new initial value yinit at the end of sol.

solext = odextend(sol, odefun, tfinal, yinit, options)

Also changes the integration options.

Description

When you find out later that the integration interval was too short, or you want to change the equation or restart with a jump in the state, odextend continues without redoing the work already done. The result is a single structure for the full interval.

Input arguments

sol: Structure returned by an ODE solver called with one output.
odefun: Function to integrate in the extension, or [] to reuse the original.
tfinal: New final time, beyond the end of sol.
yinit: Optional new initial value.

Output arguments

solext: Solution structure covering the original and the extended interval, usable with deval.

Example

Extending from t = 1 to t = 2

f = @(t, y) -y;
sol = ode45(f, [0 1], 1);
solext = odextend(sol, [], 2);
solext.x(end)
y = deval(solext, 1.5);
fprintf('%.4f %.4f\n', y, exp(-1.5))

Output

ans = 2
0.2231 0.2231

odextend