Inputting polynomial as parameter

Hi, newbie to MATLAB here, I currently get "Error using error Function is not defined for 'struct' inputs." I am wondering how to input a polynomial function into bisect2 (and fcnchk) properly. Appreciate any help!

function [x, out] = bisect2(FunFcnIn, Intv, params)
TOL = params.tol;
NO  = params.MaxIt;
[FunFcn,msg] = fcnchk(FunFcnIn,0);
if ~isempty(msg)
    error('InvalidFUN',msg);
end
...

[KSSV]

Where is this function bisect2 ?

Answer 1

[Steven Lord]

The second output of fcnchk is a struct array. The error function can accept a struct array like that second output of fcnchk OR it can accept an error message string. Don't combine the two, it won't work.

function [x, out] = bisect2(FunFcnIn, Intv, params)
TOL = params.tol;
NO  = params.MaxIt;
[FunFcn,msg] = fcnchk(FunFcnIn,0);
if ~isempty(msg)
    error(msg);
end

To confirm that this works, run this code. You will receive an error.

bisect2(1:10, 1, struct('tol', 1, 'MaxIt', 2))

Alternately, just let fcnchk throw the error itself.

function [x, out] = bisect2(FunFcnIn, Intv, params)
TOL = params.tol;
NO  = params.MaxIt;
FunFcn = fcnchk(FunFcnIn,0);

And again, check:

bisect2(1:10, 1, struct('tol', 1, 'MaxIt', 2))