anchor.diff:  
      23   IF ((f2(1)-f1(1)) .GT. (0.5d0)) THEN
   *          WRITE (*,*) 'a1>', I, R2A1, DA(1)/2.0d0
  -           r2(1,i) = r2(1,i) - lattice_unita(1,1)
  -           r2(2,i) = r2(2,i) - lattice_unita(2,1)
  -           r2(3,i) = r2(3,i) - lattice_unita(3,1)
  +           r2(1,i) = r2(1,i) - unita(1,1)
  +           r2(2,i) = r2(2,i) - unita(2,1)
  +           r2(3,i) = r2(3,i) - unita(3,1)
   
               f2(1) =  b(1,1) * r2(1,i)
        >            +  b(2,1) * r2(2,i)
  
positive.code: 	   
     28   IF ((f2(3)-f1(3)) .LE. (-0.5d0)) THEN
  *         WRITE (*,*) 'a3<', I, R2A3, DA(3)/2.0d0
            r2(1,i) = r2(1,i) + lattice_unita(1,3)
            r2(2,i) = r2(2,i) + lattice_unita(2,3)
            r2(3,i) = r2(3,i) + lattice_unita(3,3)
  
            f2(3) =  b(1,3) * r2(1,i)
       >          +  b(2,3) * r2(2,i)
  
negative.code: 	   
     24   IF ((f2(1)-f1(1)) .LE. (-0.5d0)) THEN
  *          WRITE (*,*) 'a1<', I, R2A1, DA(1)/2.0d0
             r2(1,i) = r2(1,i) + unita(1,1)
             r2(2,i) = r2(2,i) + unita(2,1)
             r2(3,i) = r2(3,i) + unita(3,1)
  
              f2(1) =  b(1,1) * r2(1,i)
       >            +  b(2,1) * r2(2,i)
  