MATLAB: Stiff differential equation solvers

Question

I'm trying to understand how the stiff differential equations are solved in ode5s and ode15i.

If my understanding is right, stiff equation solver implements BDF method if specified in the option given in the call to the solver.

What happens in implicit solver?

e.g. if dx/dt = f(x,t)

is written as

x(n+1) = x(n) + f(x(n),tn) + f(x(n+1),t(n+1))

Is it solved using non-linear equation solver?

Could someone explain? Is there any example files that are available for implementation of BDF and implicit solver?

Answer 1

There are several stiff solvers. See the "Basic Solver Selection" section on this documentation page for a table indicating which solvers are stiff and which are nonstiff. For more details about a particular solver, see the Algorithms and References sections on each solver's documentation page.