Compute selectivity-at-age from length-based selectivity curves

Defines selectivity as a parametric function of length (logistic or double-normal), then converts to selectivity-at-age by matrix-multiplying with the probability-of-length-at-age (PLA/ALK).

Usage

get_selectivity(data, par_sel, pla, len_mid)

Arguments

data

A list containing model data. Required elements: n_fishery, n_year, n_age, sel_type_f.

par_sel

Numeric matrix of dimensions [n_fishery, 6]. Each row is a real-line parameter vector. For logistic (sel_type_f == 1), only columns 1:2 are used. For double-normal (sel_type_f == 2), all 6 are used.

pla

Numeric matrix of dimensions [n_len, n_age] containing probability-of-length-at-age (age-length key). Computed via get_pla().

len_mid

Numeric vector (length n_len) of length-bin midpoints.

Value

3D array sel_fya of dimensions [n_fishery, n_year, n_age].

Details

Selectivity is currently time-invariant within each fishery (constant across years).