add check and document that "scale yes" is not supported for scaling atomic parameters with fix adapt/fep

doc/src/fix_adapt_fep.rst

@@ -307,7 +307,9 @@ the :doc:`run <run>` command.  This fix is not invoked during
 
 Restrictions
 """"""""""""
- none
+
+The keyword "scale yes" is not supported for scaling per-atom parameters
+diameter and change. You can use :doc:`fix adapt <fix_adapt>` for those.
 
 Related commands
 """"""""""""""""

src/FEP/fix_adapt_fep.cpp

@@ -434,6 +434,8 @@ void FixAdaptFEP::change_settings()
 
     } else if (ad->which == ATOM) {
 
+      if (scaleflag)
+        error->all(FLERR, "Keyword 'scale yes' is not supported with fix adapt/fep for 'atom'");
       // reset radius from diameter
       // also scale rmass to new value