I want to define a function handle that represents the constant function 
, pass an n-length vector input, and get out an n-length vector whose values are c. But there's a catch. My code is like: u_x = matlabFunction(u_x);
ans = [0 2 4];
So, I input a vector, and I get back a vector, which I would consider the "expected" behavior. But it might happen that the input function happens to have a constant derivative, like
u_x = matlabFunction(u_x);
ans = 1
Now, I put in a vector and suddenly MATLAB returns a scalar.
So if I only ever had the exceptional case, I would just do something like u_x(0) * ones(1,3) to get my desired vector of constants. But actually, I almost never have the exceptional case; most of the time the input function does not have a constant derivative, and so inputing a vector into the differentiated function returns a vector already.
What I want is for MATLAB to do what I would consider the obvious thing: If I input a vector, I get back a vector, even if the function_handle represents a constant function...how do I do?
Thanks!
