How to insert values into parameter and not function

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Nicolas Ochmann 2017-8-18

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评论： Nicolas Ochmann 2017-8-18

Hi everybody,

I hope somebody can help me out: I want to create a constraint function for fmincon with an input x which comprises of six symbolic variables x1 - x6. The variable 'parameter' depends on x which is why I want to insert their values into 'parameter'. The only way I found out is to create a function as shown below:

function [c, ceq] = constraints(x)

load ('File.mat','parameter');

parameter_function = matlabFunction(parameter);

c(1) = abs(parameter_function(x)); %Constraint

ceq = [];

end

This, however, takes a lot of time to run the code and I am quite sure because of the function creation. For this reason I would like to ask if anybody knows a way to insert the x values into 'parameter' without needing to create the function.

Thanks in advance!

Nicolas

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Stephen23 2017-8-18

@Nicolas Ochmann: function handles can be passed as arguments, so there is no reason why you cannot generate that function and pass it as a parameter (see the links I gave).

Nicolas Ochmann 2017-8-18

Perfect, thank you very much!!

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Matt J 2017-8-18

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编辑：Matt J 2017-8-18

在 MATLAB Online 中打开

   load ('File.mat','parameter');
   parameter_function = matlabFunction(parameter);
x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub, @(x) deal(parameter_function(x)^2 , [] ) )

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Matt J 2017-8-18

在 MATLAB Online 中打开

You could also modify your constraints() function as below and call fmincon as follows:

load ('File.mat','parameter');
parameter_function = matlabFunction(parameter);
x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub, @(x) constraints(x,parameter_function))
    function [c, ceq] = constraints(x,phandle)
     c=phandle(x).^2;
     ceq=[];