Simcenter Amesim and comparable Simulink solver methods for Model Exchange modes

For the AME2SL (Model Exchange) mode of the Simulink Interface, since a unique solver is used, it can be interesting to take into account the correspondences between Simcenter Amesim and Simulink solver methods to maximize the chances that the results will be similar to those obtained by the native solvers. However, since the assembled model results from the combination of a Simcenter Amesim model with a Simulink model, its behavior differs from the individual Simulink and Simcenter Amesim "component" models. Nevertheless, the table below gives an idea of more or less equivalent solvers, in term types (fixed-step or variable-step), orders of accuracy and stability.

Simcenter Amesim solver methods	Simulink solver methods
Simcenter Amesim (explicit) fixed-step solver with Euler method	ode1 (Euler's method)
Simcenter Amesim (explicit) fixed-step solver with Runge-Kutta method of order 2, 3 and 4	ode2 (Heun's method of order 2), ode3 (Bogacki-Shampine Formula of order 3), ode4 (Runge-Kutta method of order 4)
Simcenter Amesim (explicit) fixed-step solver with Adams Bashforth method of order 2, 3 and 4	ode2 (Heun's method of order 2), ode3 (Bogacki-Shampine Formula of order 3), ode4 (Runge-Kutta method of order 4)
Simcenter Amesim variable-step solver ("standard integrator")	Non-stiff system: ode45, ode23, ode113 Moderately stiff system: ode23t Stiff system: ode15s, ode23s, ode23tb

Note

As integration methods are selected automatically and dynamically by the Simcenter Amesim variable-step solver, some discrepancies might be observed between a Simcenter Amesim system integrated by Simcenter Amesim or by Simulink.

In cases where algebraic loops are formed by the complete coupled model, these loops are detected by Simcenter Amesim (SL2AMECosim) or by Simulink (AME2SL or AME2SLCosim). Simcenter Amesim switches from LSODA to DASSL integration methods whereas Simulink also disposes of specific iterative methods for resolving algebraic loops. However the names of the Simulink solvers are the same. In co-simulation modes (AME2SLCosim or SL2AMECosim), these generated algebraic loops have no influence on the solver embedded in the block that has been imported.