>> A=magic(3)

A =

     8     1     6
     3     5     7
     4     9     2

>> C=poly(A)

C =

    1.0000  -15.0000  -24.0000  360.0000

>> X=polyvalm(C,A)

X =

  1.0e-012 *

    0.4547   -0.5116   -0.0853
   -0.3340    0.1705    0.0568
   -0.2700    0.1705         0

X is approximately a matrix of zeros. The residual values are due to roundoff errors.