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Support Limitations for Simulink Software Features

The software does not support the following Simulink® software features. Avoid using these unsupported features.

Not SupportedDescription

Variable-step solvers

The software supports only fixed-step solvers.

For more information, see Fixed Step Solvers in Simulink.

Callback functions

The software does not execute model callback functions during the analysis. The results that the analysis generates, such as the harness model, may behave inconsistently with the expected behavior.

  • If a model or any referenced model calls a callback function that changes any block parameters, model parameters, or workspace variables, the analysis does not reflect those changes.

  • Changing the storage class of base workspace variables on model callback functions or mask initializations is not supported.

  • Callback functions called prior to analysis, such as the PreLoadFcn or PostLoadFcn model callbacks, are fully supported.

Model callback functions

The software only supports model callback functions if the InitFcn callback of the model is empty.

Algebraic loops

The software does not support models that contain algebraic loops.

For more information, see Algebraic Loop Concepts.

Masked subsystem initialization functions

The software does not support models whose masked subsystem initialization:

  • Modifies any attribute of any workspace parameter.

  • Deletes or creates blocks.

Variable-size signals

The software does not support variable-size signals. A variable-size signal is a signal whose size (number of elements in a dimension), in addition to its values, can change during model execution.

For more information, see Variable-Size Signal Basics.

Multiword fixed-point data types

The software does not support multiword fixed-point data types larger than 128 bits.

Nonzero start times

Although Simulink allows you to specify a nonzero simulation start time, the analysis generates signal data that begins only at zero. If your model specifies a nonzero start time:

  • If you do not select the Reference input model in generated harness parameter (the default), the harness model is a subsystem. The analysis sets the start time of the harness model to 1 and continues the analysis.

  • If you select the Reference input model in generated harness parameter, a Model block references the harness model. The software cannot change the start time of the harness model, so the analysis stops and you see a recommendation to set the Start time parameter to 0.

  • Simulink Design Verifier™ assumes zero start time for analysis and generates signal data that begins at zero. Zero start time might impact the reporting of the objective status. For example, in the test generation analysis, the software might report some objectives as Undecided with Testcases. For more information, see Simulation Basics.

Nonfinite data

The software does not support nonfinite data (for example, NaN and Inf) and related operations.

In the Relational Operator block, the software assigns the output as follows:

  • If the Relational operator parameter is isFinite, the output is always 1.

  • If the Relational operator parameter is isNan or isInf, the output is always 0.

In the MATLAB Function block, the software assigns the return value as follows:

  • For the isFinite function, the output is always 1.

  • For the isNan and isInf functions, the output is always 0.

Concurrent execution

The software does not support models that are configured for concurrent execution.

Signals with nonzero sample time offset

The software does not support models with signals that have nonzero sample time offsets.

Models with no output ports

The software only supports models that have one or more output ports.

Large floating-point constants outside the range [-realmax/2, realmax/2]

The use of large floating-point constants can cause out of memory errors or substantial loss of precision. Avoid using such constants if possible.

Symbolic Dimensions

The software does not support symbolic dimensions for test generation, property proving, or design error detection.

Simulink Strings

Models that contain blocks with string data types as block parameters are not supported. For more information, see Simulink Strings.

Parameter TuningThe software does not support parameter tuning for the parameters that are defined in the Model Workspace.
Row-major Algorithms

The software does not support models that contain MATLAB System blocks that use coder.rowMajor directive. For more information see, Use algorithms optimized for row-major array layout.

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