Conversion to double from cvx is not possible problem

[solomon]

Hello everyone, I have written a local function in matlab and called it in cvx (my function name is Re and called it in cvx and its arguments: p and p0 are vectors and N is scalar).
I’ve written my code below, my error is “Conversion to double from cvx is not possible” can you help me eliminate it?
Thank you.

cvx_begin

variable x(n);
minimize (norm(p-Re(p,p0+x,N)));
subject to
x(1) == 0.5;
x(2) == 0.5;
0 < x(3)^2+x(4)^2 <=1;
0 < x(5)^2+x(6)^2 <=1;
0 < x(7)^2+x(8)^2 <=1;
0 < x(9)^2+x(10)^2 <=1;

cvx_end

[Mark_L_Stone]

Using double incorrectly. Cannot convert from cvx to double

This is usually the result of assigning a CVX variable or expression to an element(s) of an array without having declared the array as an expression. You don’t need to (but can) declare the array if you assign the whole array all at once. E.g. A = B*C, where B is a CVX variable and C is a double precision matrix creates the expression A all at once; so A does not need to be declared as an expression. But if you assign elements of A (index into A) without having declared it as an expression of t…

You can also see some of my other related answers if you search this forum for:
conversion to double from cvx is not possible

[solomon]

Thank you so much for your attention. I imposed your comments.
But unfortunately I’ve encountered this error again.
I wrote a function in matlab and called it in this code and when optimization’s variable means x(n) becomes input argument of mu function “Re()” I get this error again.
According your tips I define a expression and define it but anything didn’t change.
My new cod is below:

cvx_begin
variable x(n);
  expression w(n)
   for i=1:n
   w(i)= p0(i)+x(i);  
   end
  Q = norm(p-(Re(p,w,Na)));
  minimize (Q)
   expression z(4);
      z(1)=x(3)^2+x(4)^2;
      z(2)=x(5)^2+x(6)^2;
      z(3)=x(7)^2+x(8)^2;
      z(4)=x(9)^2+x(10)^2;
  subject to
     x(1) == 0.5;
     x(2) == 0.5;
     z(1) <= 1;
     z(2) <= 1;
     z(3) <= 1;
     z(4) <= 1;

 cvx_end

Sincerely.

[Mark_L_Stone]

You’ll have to show us the code for your function Re