*************************************
www.BillHowell.ca,   Wed May  4 11:10:27 2016
Expression being tested : Eq_01 for un|[,k+1] :=  
(D*(un|[,k])) + (A*f_activn_uk) + (B*f_activn_uk_lagged) + (Lx*(wn|[,k]))
 
Applying write_parenthesis_aligned to result for un|[,k+1], depth of 4 : 
(+ 
   (+ 
      (+ 
         (* 
            1 un@[0,k] ) 
         (+ 
            (* A@[0,0] (f_activn@0 un@[0,k]) )
            (* A@[0,1] (f_activn@1 un@[1,k]) )
            (* A@[0,2] (f_activn@2 un@[2,k]) ) ) 
          
      ) 
      (+ 
         (* 
            B@[0,0] (f_activn@0 un@[0,k - tau@k]) ) 
         (* 
            B@[0,1] (f_activn@1 un@[1,k - tau@k]) ) 
         (* 
            B@[0,2] (f_activn@2 un@[2,k - tau@k]) ) 
          
      ) 
       
   ) 
   (* 
      Lx@[0] wn@[0,k] 
   ) 
    
) 

 

************************
Manually cleaning up the above
un|[,k+1] :=  
(+ (+ (+ (* 1 un@[0,k] ) 
         (+ (* A@[0,0] (f_activn@0 un@[0,k]) )
            (* A@[0,1] (f_activn@1 un@[1,k]) )
            (* A@[0,2] (f_activn@2 un@[2,k]) ) ) ) 
      (+ (* B@[0,0] (f_activn@0 un@[0,k - tau@k]) ) 
         (* B@[0,1] (f_activn@1 un@[1,k - tau@k]) ) 
         (* B@[0,2] (f_activn@2 un@[2,k - tau@k]) ) 
          
      ) 
   ) 
   (* Lx@[0] wn@[0,k] ) 
)