how evaluate anonymus function with array?

Question

Juan 2014-1-8

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https://ww2.mathworks.cn/matlabcentral/answers/111716-how-evaluate-anonymus-function-with-array

回答： Juan 2014-1-8

Once an anonymus function is built, how do you evaluate it with an array?

My solution does work, but it doesnt solve the answer, because I use a trick to convert the array into a string, and then eval this:

% May the handle function (or anonymus) for example
Fopt=@(x,y) sin(x).*sin(y);
x0=[1,1];
N=length(x0);
str=sprintf('%f,',x0(1:end-1));
str=sprintf('%s%f',char(str),x0(end))
eval(['Fopt(',str,')'])

My desire is to do this just like:

Fopt(x0)

Thanks

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Answer 1

Matt J 2014-1-8

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https://ww2.mathworks.cn/matlabcentral/answers/111716-how-evaluate-anonymus-function-with-array#answer_120305

编辑：Matt J 2014-1-8

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You would not write the anonymous function to take separate scalar arguments. You would write it to accept a single vector argument and use vector operations to get the result,

Fopt=@(x) sin(x(1)).*sin(x(2));

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Matt J 2014-1-8

编辑：Matt J 2014-1-8

在 MATLAB Online 中打开

Or, you could handle vectors x of arbitrary length with

Fopt=@(x) prod(sin(x));

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Answer 2

Juan 2014-1-8

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Thanks! I guessed it could not be hard.

I shall share some code it may help someone:

METOD 1, using multiples variables, each one is an array, in anonymus function:

clc,clear all,close all
Fopt=@(x,y) sin(x).*sin(y);
x0=[1,1];
x=1e1*[(-x0(1)),x0(1)];
x=linspace(x(1),x(2),1e2);
y=1e1*[(-x0(2)),x0(2)];
y=linspace(y(1),y(2),1e2);
[X,Y] = meshgrid(x,y);
f=Fopt(X,Y);
plot3(X,Y,f,'.','MarkerSize',4.55),grid on
% surf y mesh
figure(2)
surf(x,y,f),grid on
figure(3)
mesh(x,y,f);hold on,plot3(X,Y,f,'.','MarkerSize',4.55),grid on,hold off

METOD 2, using one variable , a matrix of variables , like the Matts answer,in anonymus function:

    clc,clear all,close all
    Fopt=@(x) sin(x(:,:,1)).*sin(x(:,:,2));
    x0=[1,1];
    a=1e1*[(-x0(1)),x0(1)];
    x(:,1)=linspace(a(1),a(2),1e2);
    b=1e1*[(-x0(2)),x0(2)];
    x(:,2)=linspace(b(1),b(2),1e2);
    v(:,:,1)=repmat(x(:,1),[1,length(x(:,1))])';
    v(:,:,2)=repmat(x(:,2),[1,length(x(:,2))]);
    a=x(:,1);
    b=x(:,2);
    x=v;
    plot(x(:,:,1),x(:,:,2),'.')
    f=Fopt(x);
    plot3(x(:,:,1),x(:,:,2),f,'.','MarkerSize',4.55),grid on
    % surf y mesh
    figure(2)
    surf(a,b,f),grid on
    figure(3)
    mesh(a,b,f),hold on,plot3(x(:,:,1),x(:,:,2),f,'.','MarkerSize',4.55),grid on,hold off