sigmoid: Sigmoid ogive

In flr/FLife: Methods for Modelling Life History Traits

Sigmoid ogive

Description

sigmoid ogive

Usage

## S4 method for signature 'FLQuant,FLPar'
sigmoid(age, params, ...)

Arguments

age	FLQuant, FLPar or numeric with ages
params	FLPar with age at whick probability is 0.5 (a50) and offset to 0.95 (ato95)
...	any other arguments

Details

The sigmoid ogive is an S-shaped or sigmoid curve or sigmoidal functions, Verhulst hypothesizes that small populations increase geometrically, because the supply of resources exceeds demand. Then, as supply and demand balance, population growth is constant. Finally, as demand exceeds supply, population growth decreases at the same rate that it had increased. Verhulst describes this process with an equation that enables him to predict when a population will reach any given size (see Verhulst's Figure):

Value

returns an object of same type as age e.g. FLQuant

See Also

knife, dnormal, logistic

dnormal,knife

Examples

## Not run: 
params=FLPar(a50=4,ato95=1)
age=FLQuant(1:10,dimnames=list(age=1:10))
sigmoid(age,params)

## End(Not run)

flr/FLife documentation built on March 29, 2024, 5:50 p.m.