Creating a persistent variable type single

Suppose I want to create a persistent variable but I wanted that variable's data type to be a single. By default MATLAB creates doubles. How can I have them be singles?

(As a background I am using Simulink to model a plant and its controller. I am using Embedded MATLAB as the code for the controller. I want the data types to mimic the data types in the final DSP I'll use in my product. So I want the Embedded MATLAB to run using the single rather than double)

I have tried the following but it does not work:

    persistent Accumulated_I_Error;
    if isempty(Prev_Line_Voltage_ADC) 
        Accumulated_I_Error = single(0);
    end

    ...
    Accumulated_I_Error = a + b;
    ...

I receive a compile error of: Class mismatch (single ~= double). The class to the left is the class of the left-hand side of the assignment.

Answer 1

[Sean de Wolski]

What classes are a & b?

Does the error occur on that line?

[Terry Sherman]

The error occurs on the line Accumulated_I_Error = single(0); I was hoping that the data types of 'a & b' are irrelevant if I declared the type of Accumulated_I_Error. I am in the process of casting a & b to see if that matters.