Documentation Center

  • Trial Software
  • Product Updates

AbsoluteToleranceStepSize

Initial guess for time step size for scaling of absolute error tolerance

Description

AbsoluteToleranceStepSize is a property of a SolverOptions object, which is a property of a Configset object. It is available for the ode solvers (ode15s, ode23t, ode45, and sundials).

When the AbsoluteToleranceScaling property is enabled, you can set the AbsoluteToleranceStepSize property to specify the initial guess for time step size for scaling. Then, for all state values whose size is of order 1, the software scales the absolute error tolerance for each state value individually, based on that state value's maximum absolute value during simulation and the value of AbsoluteTolerance.

    Tip   Use AbsoluteToleranceStepSize when a simulation is unsuccessful and generates numerically unstable solutions, and other corrective actions such as checking the model's kinetics do not work. You might encounter unstable solutions if you have very stiff systems in which state values change rapidly at the beginning of a simulation. To solve this, iteratively decrease AbsoluteToleranceStepSize and simulate to find the optimal setting. As a starting point, try setting this property to AbsoluteTolerance * StopTime * 0.1.

Characteristics

Applies toObject: SolverOptions
Data typedouble
Data valuesScalar in units specified by TimeUnits property. Default is [].
AccessRead/write

Was this topic helpful?