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Map Beverton-Holt steepness parameters

do_h_mapping.Rd

Internal helper called by Setup_Mod_Rec to construct the TMB/RTMB factor map for steepness_h, the Beverton-Holt steepness parameter. The steepness_h array has dimensions [n_pop x n_regions].

Usage

do_h_mapping(input_list, h_spec, rec_dd)

Arguments

input_list

Named list with $data, $par, and $map sublists. Requires $data$rec_model, $data$n_pop, $data$n_regions, and $data$rec_dd to be set by upstream setup functions.

h_spec

Character string specifying the sharing structure for steepness_h, or NULL to estimate steepness independently across all relevant dimensions. Options when non-NULL:

"est_shared_pop_r"

Single steepness value shared across all populations and regions. All elements of steepness_h share factor level 1. Required when rec_dd = "global" and n_regions > 1.

"est_shared_r"

Separate steepness per population, shared across regions within each population. Produces n_pop estimated parameters. Also valid under global density dependence.

"fix"

All steepness_h parameters fixed at their starting values (mapped to NA).

NULL

Estimate steepness independently: by population when n_pop > 1 (shared across regions within each population), or by region when n_pop = 1. Not permitted when rec_dd = "global" and n_regions > 1.

rec_dd

Recruitment density-dependence structure inherited from Setup_Mod_Rec. "global" restricts valid h_spec values to "est_shared_r", "est_shared_pop_r", or "fix", and prohibits NULL.

Value

The input input_list with $map$steepness_h set to a factor vector of length prod(dim(par$steepness_h)). Active parameters receive sequential integer indices; unused parameters (mean recruitment model or fixed steepness) are NA.

Details

When rec_model = 0 (mean recruitment), steepness has no role in the stock-recruit relationship and all elements are mapped to NA regardless of h_spec. For Beverton-Holt recruitment (rec_model = 1), mapping follows h_spec subject to the density-dependence constraint: global density dependence requires steepness to be shared across regions ("est_shared_r" or "est_shared_pop_r"), since a single pooled spawner-recruit relationship cannot support region-specific steepness values.