This lifetable identity is the same no matter what kind of lifetable is required. You can find it in any demography textbook.

lt_id_l_d(lx)

## Arguments

lx numeric. Vector of age-specific lifetable survivorship.

## Value

ndx vector of lifetable deaths.

## Details

The vector returned is the same length as lx and it sums to the lifetable radix. If the radix is one then this is the discrete deaths distribution.

## References

Preston S, Heuveline P, Guillot M (2000). Demography: measuring and modeling population processes. Wiley-Blackwell.