Passing a parameters in MATLAB.

Question

Ba Ba Black Sheep! 2017-1-3

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/318885-passing-a-parameters-in-matlab

回答： Torsten 2017-1-3

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.
 >>