MATLAB: Creating a Simbolic vector and setting assumptions on it

Question

Hi,

I'm trying to build a symbolic vector with variable dimension N, and I would like it to be real…

I managed to build the vector with the desired lenght throug str2sym, but I don't know how to set assumption "real" on its variables.

(I would like to use this vector for a linear system).

stot2=[' ']; 
for i=1:N
    A = i;
      s1=sprintf(' u%d, ',A);
      s2=sprintf(' v%d, ',A);
      s3=sprintf(' w%d ',A);
      stot2=strcat(stot2, s1, s2, s3);
end
U1=['[' stot2 ']'];
U=str2sym(U1)

Thanks for any help!

Answer 1

u = sym('u', [1 N], 'real');
v = sym('v', [1 N], 'real');
w = sym('w', [1 N], 'real');
U = [u, v, w];