Support Limitations of Simulink Design Verifier for Simulink Software Features

Simulink^® Design Verifier™ does not support the following Simulink software features. Avoid using these unsupported features.

Not Supported	Description
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 supports model callback functions only 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. uses self-modifying masks.
Variable-size signals	The software supports test generation for models with bounded variable-size signals. For more information on how to generate test cases when input signals are of variable-size, see Achieve Coverage in Models with Variable-Size Inputs. In addition, the following are the limitations for analysis: Relational boundary coverage objectives Enhanced MCDC coverage objectives Models with variable-size signals at root level input port Models with variable-size signals with maximum size 1 Unbounded variable-size signals are not supported for the analysis. Note Coverage objectives of single port logical and min-max blocks with variable size signals are not considered. The analysis is performed under the assumptions that at any step, all the variable-size inputs of a block will have same size.
Unbounded variable-size signals	Not supported.
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. If a model contains test condition or test objective blocks and no output ports are present in the model, then nominal test cases will be generated.
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 Tuning	The software does not support tuning parameters from model workspace which belong to different model workspaces and have same names. MATLAB variables from model workspace are not tunable. To make these variables tunable, convert them to `Simulink.Parameter` objects.
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.
Block Execution Order	The software does not support models with blocks having `ExecutionOrder` is set to `First` or `Last`. For more information, see Specify Block Execution Order, Execution Priority and Tag.