Initial step size

Size of first step for variable-step solver

Model Configuration Pane: Solver

Description

The Initial step size parameter specifies the size of the interval, in seconds, between the simulation start time and the next time step in simulation that uses a variable-step solver.

When you configure a referenced model to use a local solver, the Initial step size parameter of the referenced model specifies the initial step size for the local solver. (since R2025a)

Dependencies

To enable this parameter, set the solver Type to Variable-step.

Settings

auto (default) | scalar number

By default, the Initial step size value is auto, which indicates that the solver determines the initial step size by examining the derivatives of the states at the start of the simulation.

Be careful when specifying an initial step size other than auto. If the first step size is too large, the solver might step over important behavior.

When you specify an initial step size, the solver takes a smaller step than specified when error criteria are not met.

Programmatic Use

Parameter: InitialStep

Type: string | character vector

Value: scalar number

Default: "auto"

Version History

Introduced before R2006a