how use fzero with matlab coder and a function with parameters ?

I want to solve the equation f(x,p) = 0 for several values of p.

A correct way to perform this task is to write a function (here called findzero):

    function y = findzero(p)
        n = length(p);
        y = zeros(1,n);
        hf = @f;
        for il=1:n
           y(il) = fzero(@(x) hf(x,p(il)),0);
        end
    end
    function out=f(x,p)
       out = x-p;
    end

unfortunately, when I try to generate the C code of findzero with matlab coder, I encounter the following error : findzero, line 6, "anonymous functions are not supported for code generation"

How can I modify findzero in order to successfully pass it in matlab coder ?

Answer 1

[Ryan Livingston]

The typical workaround is to model an anonymous function using a sub-function with persistent variables to store the extra parameters. In your case, this function, let's reuse your f, would have the persistent p. Then, you make a call to f with 2 arguments to "set" the parameter right before the call to fzero:

% Set parameter value
f(0,p(il));
% Find root
fzero(@subfcn,0);

This answer gives an example in more detail which shows how to implement f.