Maxima: sublis() versus subst().




I am trying to use the Maxima function sublis() for parallel substitution but 
it does not seem to work for the simplified example below.  Its not clear 
what the reason is.

On the other hand the function subst() seems to work ok. Is it possible to 
(somehow set a flag and) do parallel substitution with subst() ??

Any assistance would be much appreciated.

C. Frangos.


(%i129) s;

(%o129) MATRIX([-SIN(PHI)*COS(psi1)*'DIFF(psi1,t,1)])
(%i130) sublis(['DIFF(psi1,t,1)=dpsi1],s);

SUBLIS: Bad 1st arg
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);
(%i131) subst(['DIFF(psi1,t,1)=dpsi1],s);

(%o131) MATRIX([-dpsi1*SIN(PHI)*COS(psi1)])
(%i132)