How can I replace some symbolic values in a matrix?

Hello!

I have a (symbolic) matrix A and its components depend on some symbolic variables (x, y and z). I want to replace the symbolic values with zero and I used subs function:

A = subs(subs(subs(A, x, 0), y, 0), z, 0);

and it doesn’t work (the replacement don’t take place) It doesn’t work either:

A = subs(A, x, 0);

What can I do to replace my symbolic variables with zero in this case?

Thanks!

[Dishant Arora]

The replacement doesn't take place, then what do you get?? It should work fine.

[Dina Irofti]

The same matrix A, with the symbolic elements unreplaced

Answer 1

[Walter Roberson]

Did you assign a value to x, y, or z at the MATLAB level? If so then when it is the value of x, y, or z that is going to be used in the subs(), not the symbol. You might be able to use

subs(A, {sym('x'), sym('y'), sym('z')}, {0, 0, 0})

[Walter Roberson]

What error did you get and which MATLAB version are you using?

[Dina Irofti]

This is the error

Error using mupadmex
Error in MuPAD command: Invalid variable. [stdlib::diff]

Error in sym/subs>mupadsubs (line 146)
G = mupadmex('symobj::fullsubs',F.s,X2,Y2);

Error in sym/subs (line 119)
    G = mupadsubs(F,X,Y);

Version: R2012a

[Dina Irofti]

You were right: it works if I use another version of Matlab.

Thanks!