anti_aliasing filtering at each step is safer

src/stepon.F90

@@ -115,7 +115,7 @@ CONTAINS
       LOGICAL :: checkf_
       REAL    :: sum_
       !! Maybe useless
-      ! IF(LINEARITY .NE. 'linear') CALL anti_aliasing   ! ensure 0 mode for 2/3 rule
+      IF(LINEARITY .NE. 'linear') CALL anti_aliasing   ! ensure 0 mode for 2/3 rule
       ! IF(LINEARITY .NE. 'linear') CALL enforce_symmetry ! Enforcing symmetry on kx = 0
 
       mlend=.FALSE.