shape: Access or assign shape of the production function

In cttedwards/bdm: Bayesian biomass dynamics model

Access or assign shape of the production function

Description

This function can used to access or assign the shape of the generalised production function. The shape is assumed to be fixed on input and is therefore contained within the bdmData object class as the parameter n.

Usage

shape(object, ...)

## S4 method for signature 'bdmData'
shape(object, par = "phi")

shape(object, ...) <- value

## S4 replacement method for signature 'bdmData,numeric'
shape(object) <- value

Arguments

object	a bdmData class object
...	additional arguments to the generic function
par	a character string of either n or phi
value	a numeric value specifying the value of either n or phi

Details

The bdm package assumes by default a generalised Fletcher-Schaefer hybrid production function. The inflection points occurs at:

φ = B_{MSY}/K = (1/n)^(1/(n-1)).

The discontinuity in the relationship between phi and n is accommodated by assuming φ = 1/e at n = 1.

Examples

# initialize bdmData object
dat <- bdmData(harvest = 20:30, index = runif(11))

# access default shape
shape(dat, 'phi')
shape(dat, 'n')

# assign shape
shape(dat) <- 0.4
shape(dat)
shape(dat, 'n')

cttedwards/bdm documentation built on Oct. 11, 2022, 7:52 p.m.