FA-63367 / Actuarial life tables / Member archive

Life table person-years and expectation: Person-years start from the wrong survivor count · case 02

Life expectancies are overstated by about one year.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Input l (survivors by age, last entry is the open interval) and m_open (per mille central rate of the open interval, <=0 -> 'invalid open rate'). L_x = l_{x+1} + d_x/2, L_open = l_open/m, T_x = sum of L from x, e_x = T_x/l_x rounded to 4 places (None where l_x=0).

Why this case matters

Life-table arithmetic compounds across ages, so one misplaced index or assumption shifts every downstream value.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
table 0	`[5.938, 4.9568, 3.9749, 2.9899, 2.0]`	`[5.9161, 4.9389, 3.9622, 2.9832, 2.0]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.