Check solver type selection

To improve simulation, check that the model uses the appropriate solver type. The selection of an explicit or implicit solver depends on the approximation of the model stiffness at the beginning of the simulation.

	If the Model...	Use this Solver
	Represents a stiff system	ode15s
	Does not represent a stiff	ode45
	system

The selection of a proper solver is challenging and often performed by trial and error. Performance Advisor uses the following heuristic to choose between explicit and implicit solvers:

	If the Original Solver Is...	Performance Advisor...
	Variable step solver	Calculates the system stiffness at 0 first.
		Then
		• If the stiffness is greater than 1000,
		Performance Advisor chooses ode15s.
		• If the stiffness is less than 1000,
		Performance Advisor chooses ode45.
	Fixed-step continuous	• If the stiffness is greater than 1000,
	solver	Performance Advisor chooses ode14x.
		• If the stiffness is less than 1000,
		Performance Advisor chooses ode3.

This heuristic works best if the system stiffness does not vary during simulation. If the system stiffness varies with time, the solver that Performance Advisor suggests might not be the best for your system.

Check solver type selection

See Also