dublogistic.f: A double logistic selectivity function

In duplisea/dublogistic: Explore the double logistic function as a selectivity curve for fisheries modelling

Description

This is a useful function because it can not only mimic standard sigmoidal selectivity but also a dome shaped selectivity curve if necessary. Set minsell.upper=max.sel for a simple logisitic curve. A default parameterisation is provided simply to give you something to start with that might seem half decent.

Usage

dublogistic.f(L, inflection1 = 38, inflection2 = 90, slope1 = 0.3,
  slope2 = 0.1, max.sel = 1, minsel.upper = 0.4, plot = F)

Arguments

L	a length or length vector for which you want a selectivity estimates
inflection1	the inflection point of the first part of the selectivity curve
inflection2	the inflection point of the second part of the selectivity curve
slope1	the slope of the first part of the curve
slope2	the slope of the second part of the curve
max.sel	the maximum selectivity level
minsel.upper	the asymptotic minimum selectivity on the right side of the curve. Dome shaped curves between 0 and max.sel, =max.sel for a regular logistic curve
plot	T if you want a plot of the curve

duplisea/dublogistic documentation built on June 14, 2019, 3:26 p.m.