create symbolic variables

My problem is the following:

 if I have an array ij then have to create variables ij.
 ex.:

a = [ 1 2; 3 4]

then

b = [x11 x21;x12 x22]

have to create the variables corresponding to the size of the matrix.

These variables can be syms or string. Can I convert the string to syms after.

thanks advanced

[Artur M. G. Lourenço]

in fact there str2sym. Sorry

Answer 1

[Andrei Bobrov]

a = [1 2;3 4];
x = sym('x%d%d',size(a)).'

please read: doc sym

Answer 2

[Artur M. G. Lourenço]

My god, I ask my five excuses. Always read the doc before asking a question and this time I have not read. Thank you, this is not repeated.

[Walter Roberson]

Though to be fair, this feature is new in R2011b. (Or was it R2010b?)

[Artur M. G. Lourenço]

true