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Maximum-likelihood fit (non-spatial, fixed effects only) of the removal / sequential-depletion abundance model with a Poisson or negative-binomial abundance mixing distribution. Pass k removes y_{ik} ~ Binomial(N_i - sum_{l<k} y_{il}, p_{ik}) of the individuals still present, and the latent N_i ~ Poisson(lambda_i) (or NegBin(lambda_i, r)) is summed out in closed form (truncation K_max). Optimisation is the same analytic inner-Newton / observed-Fisher path the N-mixture uses; the per-site detection arm sees the depleting available count rather than the full N.

Usage

removal_laplace(
  y,
  site_idx,
  X_lambda,
  X_p,
  mixture = c("P", "NB"),
  beta_lambda_init = NULL,
  beta_p_init = NULL,
  log_r_init = NULL,
  r_max = 1e+05,
  K_max = NULL,
  max_iter = 100L,
  tol = 1e-06,
  verbose = FALSE
)

Arguments

y

Integer vector of per-pass removals (long form), passes in order.

site_idx

Integer vector, same length as y, 1-based site index; a site's passes must appear in pass order (the depletion order).

X_lambda

Numeric matrix [n_sites x p_lambda] of abundance covariates.

X_p

Numeric matrix [n_obs x p_p] of per-pass detection covariates.

mixture

"P" (Poisson, default) or "NB" (negative binomial).

beta_lambda_init, beta_p_init, log_r_init

Optional warm starts.

r_max

Upper bound on the NB size r (NB only, default 1e5).

K_max

Marginal-sum truncation; defaults to max(site removal total) + 100. Must be >= the largest per-site removal total.

max_iter

Newton iteration budget (default 100).

tol

Gradient-norm convergence tolerance (default 1e-6).

verbose

Print per-iteration progress.

Value

A list of class nmix_fit (the shared count-marginal fit shape): beta_lambda, beta_p, mixture, log_r / r (NB), log_lik, vcov, H_obs, n_iter, converged, grad_norm, per-site mean_N / var_N / boundary_weight.

References

Royle, J. A. (2004). N-mixture models for estimating population size from spatially replicated counts. Biometrics 60, 108-115. Dorazio, R. M., Jelks, H. L., Jordan, F. (2005). Improving removal-based estimates of abundance. Biometrics 61, 1093-1101.