  fsign = 1.d0
  t_val = time
 !sui!write(6,*) "              getdetAdd t_val",t_val
  IF ( t_val .LT. 0.d0 ) THEN
    ! if t < 0 op%F(t,activeF,activeF) = -op%F(t+beta,activeF,activeF)
    t_val = t_val + op%beta
    fsign  = -1.d0 
  END IF

  ratioh = t_val * op%inv_dt + 1.d0 ! t / delta t
 !sui!write(6,*) "              getdetAdd ratioh",ratioh
  index = INT(ratioh)
 !sui!write(6,*) "              getdetAdd index",index
  ratioh = ratioh - DBLE(index)
 !sui!write(6,*) "              getdetAdd ratioh",ratioh

  ! first order interpolation
 !sui!write(6,*) "              getdetAdd fsign",fsign  
 !sui!write(6,*) "              getdetAdd Fs   ",op%F(index,iflavora,iflavorb)
 !sui!write(6,*) "              getdetAdd Fs   ",op%F(index+1,iflavora,iflavorb)
  ! index + 1 can be sizeHybrid + 1 => value is 0 (cf. BathOperatoroffdiag_init routine)
  hybrid = fsign * (op%F(index,iflavora,iflavorb) + &
    ratioh * ( op%F(index+1,iflavora,iflavorb) - op%F(index,iflavora,iflavorb) ))
