Passing a parameters in MATLAB.

Suppose, I have the following functions:

 function [f,g] = rosenbrockwithgrad(x, a, b)
    % Calculate objective f
    f = rosenbrock(x, a, b);  

    % gradient required
    if nargout > 1 
        g = gradient(x);
    end
end

 function out = rosenbrock(x, a, b) 
    xx = x(1);
    yy = x(2);

    out = (1 - xx + a)^2 + 100*(yy - b - (xx-a)^2)^2;
end

I need to use them in the following routine,

 function [x, fval, eflag, iter, fcount] = 
    Optimization_With_Analytic_Gradient(a, b, start_point)

    x0 = start_point;

    %   inline function defitions
    %fungrad = @(x)deal(fun(x),grad(x));

    % options setup
    options = optimoptions( 'fminunc', ...
                            'Display','off',...
                            'OutputFcn',@bananaout,...
                            'Algorithm','trust-region', ...
                            'GradObj','on');
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    % calling fminunc
    [x, fval, eflag, output] = fminunc(@rosenbrockwithgrad, x0, options);
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    iter = output.iterations;
    fcount = output.funcCount;

    %   plot window title
    title 'Rosenbrock with Analytic Gradient...'    

    disp('Optimization_With_Analytic_Gradient...');
end

Note the use of fminunc().

So, How can I do that?

My code generates the following Error

 >> main
 Error using rosenbrockwithgrad (line 3)
 Not enough input arguments.

 Error in fminunc (line 271)
        [f,GRAD] = feval(funfcn{3},x,varargin{:});

 Error in Optimization_With_Analytic_Gradient (line 24)
    [x, fval, eflag, output] = fminunc(@rosenbrockwithgrad, x0, options);

 Error in main (line 53)
        [x, fval, eflag, iter, fcount] = Optimization_With_Analytic_Gradient(a, b, starting_point);

 Caused by:
    Failure in initial user-supplied objective function evaluation. FMINUNC cannot continue.
 >>

Answer 1

[Torsten]

[x, fval, eflag, output] = fminunc(@(x)rosenbrockwithgrad(x,a,b), x0, options);

Best wishes

Torsten.