Advanced Simulation Settings - MapleSim Help

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Advanced Simulation Settings

In the Advanced Simulation section of the Simulation Settings tab ( ) you can specify the simulation start time, a state snapshot to use, compilation options, and other settings. Some of these settings are specific to the solver type (variable or fixed) selected in your Simulation settings.

The following table describes the parameters available in the Advanced Simulation section.

 

Parameter

Default

Solver Type

Description

ts

0

All

The simulation start time. You can specify any floating-point value, including negative values.

Note: The simulation start time affects the end time of your simulation, but not the duration time for the simulation, td. The end time for the simulation is given by td + ts.

Use Snapshot

None

All

A snapshot captures the state of your simulation at a specific time. If you use a snapshot in your simulation, you can override the initial conditions used in your model and replace them with the state your model was in at the time of the snapshot.

See Taking a Snapshot and Using a Snapshot in a Simulation for more information on creating and using snapshots.

Jacobian

Symbolic

All

Choose between a symbolic or numeric approximation to the system Jacobian. A symbolic formulation results in faster and more accurate simulations but can take longer to formulate.

Note: A numeric formulation can only be used with stiff solvers (Rosenbrock or Implicit Euler).

Baumgarte

All

Apply Baumgarte constraint stabilization to your model. When selected, you can enter values for the derivative gain (α) and the proportional gain (β) that are appropriate for your model.

Projection

All

Apply constraint projection to your model. When selected, the solution found at each step of the simulation is projected back to the constraint manifold. The projection ends when either the maximum number of Projection Iterations has been reached or the defect falls below the Projection Tolerance.

Projection Iterations

50

All

The maximum number of constraint projection iterations.

Note: This parameter is only available when Projection is selected.

Projection Tolerance

0.000010

Fixed

The tolerance value at which the projection iterations are terminated. You can specify any positive floating-point value.

Event Projection

Fixed

When selected, constraint projection occurs during event iterations, which results in slower integration. When cleared, the simulation could fail if the event changes the solution enough to not allow the application of constraint projection at the next step.

Event Iterations

100

All

The maximum number of event iterations allowed before the integrator throws an error. You can specify any positive integer value.

Event Hysteresis

1.0 10-7

Fixed

The width of the event hysteresis band. You can specify a floating-point value greater than or equal to zero. If set to zero, this parameter is disabled.

Initial Hysteresis

1.0 10-10

Variable

The width of the event hysteresis for all event triggers at the start of the simulation. You can specify a floating-point value greater than or equal to zero.

Index 1 Error Control

Variable

When selected, error control is applied to all algebraic variables. By default, error control is only applied to algebraic variables that trigger events, are plotted, or are outputs of functions.

Index 1 Tolerance

1.0

Variable

Controls the relative error on algebraic variables compared to differential variables. For example, a value of 10 means that algebraic variables can have 10 times the error of differential variables.

Minimum Step Size

0

Variable

Set the minimum step size.

Maximum Step Size

no value

Variable

Set the maximum step size.

Scaling

None

All

Specifies the method of variable scaling to apply to the system. The available choices are:

• 

None: do not apply scaling

• 

Minimum: use the minimum nominal value

• 

Maximum: use the maximum nominal value

• 

Geometric: use the geometric mean of the nominal values

Minimize Events

Variable

This option specifies whether to use heuristics to reduce the number of events encountered during your simulation. When selected, the mapping of piecewise transitions into events does not occur.

Plot Events

All

Specifies whether to include extra plot points at event points during the simulation.

Solver Diagnostics

All

When selected, the simulation generates diagnostics describing constraint iterations, constraint residual, event iterations, and step size, and plots them after the simulation is complete in a Solver Diagnostics plot window in the Simulation Results tab. For systems with the projection option cleared, this incurs additional computational cost.

For models with an inconsistent system of equations or run-time issues, select this option to display details about the variables, equations, and components that are causing the errors (see Using Solver Diagnostics for Inconsistent Systems and Using Solver Diagnostics for Run-time Issues and Performance).

Compiler

Variable

Specifies whether a native C compiler is used during the simulation. When this option is selected, Maple procedures generated by the simulation engine are translated to C code, which is compiled by an external C compiler.

If your model is complex, you may want to select this option to reduce the time required to run a simulation.

Compile Optimized

All

Optimize the code during compilation. If this parameter is cleared, compile time will be reduced but your simulation will take longer to run.

See Also

Adding Probes to a Model

Changing Snapping Options for the 3-D Workspace

Changing the Flow Direction of a Probe

Editing Probe Values

Enabling View Change Animations

Multibody Settings

Running a Simulation

Simulation Settings

Specifying the Radius of Implicit Geometry

The 3-D Visualization Environment

Using a Parameter Set in a Simulation

Using Solver Diagnostics for Inconsistent Systems

Using Solver Diagnostics for Run-time Issues and Performance

Viewing Simulation Results

Visualization Settings