MATLAB: Creating a function getting the graident and passing variables to them

functionmatlab functionmultiplesymbolicvariable

Hi !

I am trying to creat a function that I can both use to pass values and compute the gradient of that function.

I tried both these :

but the for the first I cant pass values and the 2nd the gradient function in matlab does not work

syms x1 x2
f= 100*(x2-x1^2)^2 + (1+x1)^2;
gr= gradient(f)
%%%%%% other way 
syms x1 x2 
f=@(x1,x2) 100*(x2-x1^2)^2 + (1+x1)^2;
gr= gradient(f)

Is this that you want?

syms f(x1,x2)
f(x1,x2)= 100*(x2-x1^2)^2 + (1+x1)^2;
gr(x1,x2) = gradient(f,[x1,x2])

Then you can compute

f(0,0)
gr(0,0)

Let A be your 47X2 matrix.

q = A(:,1) ; 
v = A(:,2) ; 
dq_dv = diff(q)./diff(v) ;   % dq/dv 
dv_dq = diff(v)./diff(q) ;   % dv/dq

There are issues with the definition of 'myfun'. Compare it with the following to see the errors.

function f = myfun(x)
x1 = x(1);
x2 = x(2);
x3 = x(3);
f = (1./(1+(x1-x2).^2)) + sin(0.5*pi.*x2.*x3) + exp(((-x1+x)./x2)-2).^2;
end