FA-63730 / Actuarial life tables / Member archive

Double-decrement death and lapse table: Year-end lapses are applied to the starting count · case 05

Lapses are counted on lives who died during the year.

Member previewVariant 5 · 3 implementations · 9 checks per implementation

Case contract

Input qd, qw (associated single-decrement rates per 100000, equal lengths else 'length mismatch'), timing udd|eoy, radix. UDD in each decrement: q(d)=q'd(1-q'w/2), q(w)=q'w(1-q'd/2). eoy (lapses at year end): q(d)=q'd, q(w)=(1-q'd)q'w. Each year counts are rounded half-up and subtracted from l. Return [[deaths, lapses] per year, final l].

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
eoy decrement table 2	`[[[666, 12358], [767, 7941], [892, 7430], [1037, 7369], [1177, 3393], [1419, 1477]], 45151]`	`[[[666, 12268], [768, 7872], [895, 7351], [1041, 7272], [1184, 3338], [1430, 1445]], 45547]`	Failed

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