For code generation, how to overcome the issue of having the size of a symbolic dimension must be greater than 1.

I am developing a generic model with interface signals and parameters having symbolic dimensions, at some cases the dimension is required to have a value of 1 but in code generation this is not feasible.

How to overcome this without just generating the code with a value greater than 1 then changing it later or is their any clean solution to my request?

Why is this even a limitation, it is boggling to have this issue to start with.

Thanks in advance

Answer 1

[Nithin]

Hi @Omar Ashraf,

The limitation of having symbolic dimensions greater than 1 often arises from the need to optimize for performance and memory usage in generated code. Arrays with a dimension of 1 can sometimes be treated differently in memory allocation and access patterns, potentially leading to inefficient code. By enforcing a minimum dimension greater than 1, the code generation process can ensure more consistent and predictable behavior across different platforms and compilers. These strategies should help you manage symbolic dimensions more effectively.

To address this issue, here are some strategies you can consider:

• Use conditional compilation in your generated code to handle dimensions of 1. This involves generating code with a dimension greater than 1 and using preprocessor directives to adjust the code for a dimension of 1.
• Use variant subsystems in Simulink to handle different dimensional cases. You can define different subsystems for different dimension sizes and use a variant control variable to switch between them. Kindly refer to the following documentation to understand more about “variant subsystems”: https://www.mathworks.com/help/simulink/slref/variantsubsystem.html
• Define custom storage classes that can handle single-element arrays differently. This approach requires more advanced knowledge of Simulink's data management, refer to the following documentation to know more about "Custom Storage Class Designer": https://www.mathworks.com/help/ecoder/ug/design-custom-storage-classes-and-memory-sections.html

Refer to the following MathWorks documentation to understand more about symbolic dimensions and its limitations: https://www.mathworks.com/help/rtw/ug/symbolic-dimensions-supported-block-constraints-and-limitations.html

Hope this resolves this issue.