FA-63343 / Actuarial life tables / Member archive

Life table survivors from mortality rates: Survivors are rounded from the cumulative product instead of step by step · case 03

Published l_x values drift from the stepwise-rounded table.

Member previewVariant 3 · 3 implementations · 12 checks per implementation

Case contract

Input q (per 100000, last must be 100000 else 'open table'; any outside [0,100000] -> 'invalid q') and radix (<=0 -> 'invalid radix'). l_0 = radix; l_{k+1} = l_k*(1-q_k) rounded half-up at every age; d_k = l_k - l_{k+1}. Return [l, d].

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
closed table 0	`[[30585, 30327, 30028, 29686, 29301, 28866, 28375, 27826, 27215, 0], [258, 299, 342, 385, 435, 491, 549, 611, 27215]]`	`[[30585, 30327, 30028, 29686, 29301, 28866, 28376, 27826, 27215, 0], [258, 299, 342, 385, 435, 490, 550, 611, 27215]]`	Failed

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