FA-65735 / Ecological population dynamics / Member archive

Discrete delayed logistic (Hutchinson) with lag: lag index · case 05

Oscillations are weaker than the stated delay produces.

Member previewVariant 5 · 3 implementations · 6 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, 17.2, 29.584, 49.1804, 76.8852, 108.1433, 128.141, 119.7931, 92.8243], 28.141]`	`[[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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