Substituting a syms variable with another syms variable equation

Error code:

??? Subscript indices must either be real positive integers or logicals.

Error in ==> EigenValuesVectors4x4ToTensorFactor at 10
f=sym(zeros(4,4,4))

Code:

    syms T11 T12 T13 T14 T21 T22 T23 T24 T31 T32 T33 T34 T41 T42 T43 T44

    f=sym(zeros(4,4,4))

    %MatLab does not like the substitution of a syms variable with another syms variable equation.  Is there any way around this?
    %h(i,k)  is a 4x4 matrix with syms formula in each cell

    ta13=solve(h(1,3),'T14')
    ta14=solve(h(1,4),'T14')
    tb11=subs(h(1,1),'T14',ta14)
    tb12=subs(h(1,2),'T14',ta14)

[Walter Roberson]

Is it possible that you had code before that which creates a variable with the name "sym" ?

which sym

Answer 1

[Philosophaie]

No the "sym" in "f=sym(zeros(4,4,4))" creates "f" as a symbolic zero matrix.

[Walter Roberson]

It cannot both create "f" as a symbolic matrix and complain about a subscript.

Your posted error message refers to line 10, but the "f=" line it is complaining about is at most line 3. What is before that in the code ?

Answer 2

[Walter Roberson]

Please post the result of

which sym
class(sym)    %might generate error message

Also, what does

sym('abc')

return?