FA-65738 / Ecological population dynamics / Member archive

Discrete delayed logistic (Hutchinson) with lag: pre-history · case 03

Early growth explodes because the population is assumed absent before time 0.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

hist[0]=N0; N[t+1] = max(0, N[t] + r*N[t]*(1 - N[t-lag]/K)) where values before time 0 equal N0; return [history rounded 4, overshoot max(0, max(history)-K) rounded 4].

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: daphnia with 2 step lag	`[[10.0, 18.0, 32.4, 55.728, 92.2856, 142.1936, 192.5552, 204.4388, 135.4307], 104.4388]`	`[[10.0, 17.2, 29.584, 50.8845, 84.5904, 132.2425, 184.2037, 206.9118, 153.541], 106.9118]`	Failed

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