Code Analyzer detects what appears to be a variable-size array. The code MATLAB generates for indexing a variable-size array is less efficient than for a fixed-size array. The generated code might be a bit bigger and slower than if the array were fixed-size.

If you want this behavior, or if you have already indicated a variable size with the MATLAB function coder.varsize, suppress the message as described in Adjust Code Analyzer Message Indicators and Messages.

Otherwise add a statement that initializes the variable to a size that is large enough for the application.