FA-65457 / Ecological population dynamics / Member archive

Leslie matrix projection with optional plus group: survival subdiagonal · case 02

Classes age without moving: survivors come from the destination class.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

Births new[0] = sum f_i*n_i; survivors new[i+1] = s_i*n_i; with plus_group the last class also retains s_last*n_last; ratio is total(t)/total(t-1) of the final year (None if the previous total was 0 or no years); return [final vector rounded 4, total rounded 4, ratio rounded 6].

Why this case matters

Population projections set harvest quotas, conservation status and pest-control timing; a wrong update order, boundary or rate conversion silently changes management advice.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression: three-class bird	`[[27.24, 3.2, 6.86], 37.3, 0.556716]`	`[[96.48, 44.4, 26.88], 167.76, 0.94566]`	Failed

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