MATLAB Language Features Supported for Automated Fixed-Point Conversion

Automated fixed-point conversion tools and workflows in the Fixed-Point Designer™ software do not support all features of the MATLAB^® language. For best results, avoid unsupported features of the MATLAB language.

To replace MATLAB functions that do not support fixed-point data types, use coder.float2fixed.skip. (since R2024b) For fixed-point conversion using the DataTypeWorkflow.Converter object, use DataTypeWorkflow.FunctionReplacement to specify replacements for unsupported functions. (since R2025a) In the iterative fixed-point conversion workflow in the Fixed-Point Tool, use the function replacement option to specify replacements for unsupported functions. (since R2026a)

MATLAB Language Features Supported for Automated Fixed-Point Conversion

Fixed-Point Designer supports these MATLAB language features in automated fixed-point conversion workflows:

• N-dimensional arrays

• Matrix operations, including deletion of rows and columns

• Variable-size data (see Generate Code for Variable-Size Arrays (MATLAB Coder)). Range computation for variable-size data is supported via simulation mode only. Variable-size data is not supported for comparison plotting.

• Subscripting (see Incompatibility with MATLAB in Matrix Indexing Operations for Code Generation (MATLAB Coder))

• Complex numbers (see Code Generation for Complex Data)

• Signed and unsigned integer classes (see Integers)

• Double- and single-precision floating point numbers (see double and single)

• Boolean variables (see logical)

• Fixed-point data types

• Double-precision, single-precision, and integer math

• Fixed-point arithmetic (see Code Acceleration and Code Generation from MATLAB)

• Program control statements if, switch, for, while, and break

• Arithmetic, relational, and logical operators

• Global variables

• Persistent variables

• Function handles

• Structures, including arrays of structures. Range computation for structures is supported via simulation mode only.

• Characters

• Local functions when used outside of a class. Local functions called from inside class definitions are not supported.

• The complete set of Unicode^® characters is not supported for code generation. Characters are restricted to 8 bits of precision in generated code. Because many mathematical operations require more than 8 bits of precision, it is recommended that you do not perform arithmetic with characters if you intend to convert your MATLAB algorithm to fixed point.

• MATLAB classes. Range computation for MATLAB classes is supported via simulation mode only.

  Automated conversion supports:

  • Class properties

  • Constructors

  • Methods

  • Specializations

  Automated conversion does not support class inheritance or namespaces. For more information, see Fixed-Point Code for MATLAB Classes.

• Ability to call functions (see Resolution of Function Calls for Code Generation)

• Subset of MATLAB toolbox functions (see Functions Supported for Code Acceleration or C Code Generation).

• Subset of DSP System Toolbox™ System objects.

  The DSP System Toolbox System objects supported for automated conversion are:

  • dsp.FIRDecimator (DSP System Toolbox)

  • dsp.FIRInterpolator (DSP System Toolbox)

  • dsp.FIRFilter (DSP System Toolbox) (Direct Form and Direct Form Transposed only)

  • dsp.FIRRateConverter (DSP System Toolbox)

  • dsp.VariableFractionalDelay (DSP System Toolbox)

MATLAB Language Features Not Supported for Automated Fixed-Point Conversion

Fixed-Point Designer does not support these features in automated fixed-point conversion workflows:

• Anonymous functions

• Cell arrays

• String scalars

• Objects of value classes as entry-point function inputs or outputs

• Java^®

• Nested functions

• Recursion

• Sparse matrices

• try/catch statements

• varargin, varargout, or generation of fewer input or output arguments than an entry-point function defines

• Dot indexing properties of fixed-point data types.

  Avoid using properties of fixed-point types in MATLAB code being converted.

• Dynamic field or property references

• Handle class destructors

• Arguments blocks

• Property validation functions

• Functions that do not support fixed-point data types