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Simplified Initialization Mode

Initialization mode controls how Simulink® handles:

  • Initialization values for conditionally executed subsystems.

  • Initial values for Merge blocks.

  • Discrete-Time Integrator blocks.

  • Subsystem elapsed time.

The default initialization mode for a model is simplified. This mode uses enhanced processing to improve consistency of simulation results and helps to:

  • Attain the same simulation results with the same inputs when using the same blocks in a different model.

  • Avoid unexpected changes to simulation results as you modify a model.

When to Use Simplified Initialization

Use simplified initialization mode for models that contain one or more of the following blocks:

  • Conditional subsystem blocks.

  • Merge blocks. If a root Merge block has an empty matrix ([]) for its initial output value, simplified mode uses the default ground value of the output data type.

  • Discrete-Time Integrator blocks. Simplified mode always uses the initial value as both the initial and reset value for output from a Discrete-Time Integrator block.

Use simplified mode if your model uses features that require simplified initialization mode, such as:

  • Specify a structure to initialize a bus.

  • Branch merged signals inside a conditional subsystem.

Set Initialization Mode to Simplified

Simplified mode is the default initialization mode when creating a new Simulink model. If your model is using classic mode, you might need to make changes after you select simplified mode. See Convert from Classic to Simplified Initialization Mode.

  1. Open the Configuration Parameters dialog box. On the Modeling tab and from the Setup section, select Model Settings .

  2. In the search box, enter Underspecified initialization detection.

  3. From the drop-down list, select Simplified.

For examples configured to use simplified mode, see Identity Transformation Can Change Model Behavior, Inconsistent Output with Discrete-Time Integrator or S-Function Block and Execution Order Affecting Merge Block Output.

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