A function handle constructed by a symbolic function and another function handle

Hello,

I have a simple problem but unfortunately could not figure out how to fix it. Consider the following

syms sigma(x) 
par=sym('par', [1 2]);
sigma(x)=par(1)+par(2)*x;
f=@(x)x;

Now, imagine I want to construct a function handle H using f and sigma as bellow:

sigma = matlabFunction(sigma);
H = @(x,par) sigma(x,par)+f(x);

Now, you see my problem. For matlab H has 2 inputs: x and par. But, I am struggling to define H(x,par(1),par(2)) = sigma(x,par(1),par(2))+f(x)

Thanks for your help in advance!

Babak

Answer 1

[Dyuman Joshi]

You can do this without symbolic variables.

The definition is correct, just call the function with appropriate inputs -

sigma = @(x,par) par(1)+par(2)*x;
f=@(x)x;


H = @(x,par) sigma(x,par)+f(x)

H = function_handle with value:
    @(x,par)sigma(x,par)+f(x)

H(1,[1 2])

ans = 4

[Mohammad Shojaei Arani]

Thanks Dyuman,

Unfortunately, I cannot define sigma as a function handle initially (the reason is that I need to work on its derivatives first ...). So, I am seeking an answer to my question which considers sigma being defined as a

symbolic function (as I defined). When I convert sigma to a function handle using matlabFunction then I get

@(x,par1,par2)par1+par2.*x

Unfortunately, this does not let me to do what I intend to do

[Dyuman Joshi]

I see. In that case, modify the symbolic function to anonymous function conversion as follows -

syms sigma(x) 
par=sym('par', [1 2]);
sigma(x)=par(1)+par(2)*x;
f=@(x)x;

%Generate function with vector input arguments
sigma = matlabFunction(sigma,"Vars",{x par})

sigma = function_handle with value:
    @(x,in2)in2(:,1)+in2(:,2).*x

H = @(x,par) sigma(x,par)+f(x)

H = function_handle with value:
    @(x,par)sigma(x,par)+f(x)

H(1,[1 2])

ans = 4

[Mohammad Shojaei Arani]

This is a wonderful answer!

Thanks for your great help!

[Dyuman Joshi]

You are welcome!

Glad to have helped :)