sigmoid_weight: Weight based sigmoidal selectivity function

In mizer: Dynamic Multi-Species Size Spectrum Modelling

Weight based sigmoidal selectivity function

Description

A sigmoidal selectivity function with 50% selectivity at weight sigmoidal_weight =w_{\text{sigmoid}} and width sigmoidal_sigma =\sigma.

S(w) = \left(1 + \left(\frac{w}{w_{\text{sigmoid}}}\right)^{-\sigma}\right)^{-1}

Usage

sigmoid_weight(w, sigmoidal_weight, sigmoidal_sigma, ...)

Arguments

w	Vector of sizes.
sigmoidal_weight	The weight at which selectivity is 50%.
sigmoidal_sigma	The width of the selection function.
...	Unused

Details

You would not usually call this function directly. Instead, set the sel_func column in gear_params() to "sigmoid_weight" and provide sigmoidal_weight and sigmoidal_sigma as additional columns. setFishing() will then call this function automatically when calculating the selectivity array.

Value

Vector of selectivities at the given sizes.

See Also

gear_params() for setting the selectivity parameters.

Other selectivity functions: double_sigmoid_length(), knife_edge(), knife_edge_length(), sigmoid_length()

Examples

sigmoid_weight(w = c(1, 10, 100, 1000),
               sigmoidal_weight = 100, sigmoidal_sigma = 3)

mizer documentation built on Aug. 31, 2026, 5:08 p.m.