W1.3 {drc}R Documentation

The three-parameter Weibull functions

Description

'W1.3' provides the three-parameter Weibull function, self starter function and names of the parameters.

Usage

  W1.3(fixed = c(NA, NA, NA), names = c("b", "d", "e"))
  
  W2.3(fixed = c(NA, NA, NA), names = c("b", "d", "e"))

Arguments

fixed numeric vector. Specifies which parameters are fixed and at what value they are fixed. NAs for parameter that are not fixed.
names a vector of character strings giving the names of the parameters. The default is reasonable.

Details

The three-parameter Weibull model is given by the expression

f(x) = 0 + (d-0)exp(-exp(b(log(x)-e))).

The function is asymmetric about the inflection point, that is the parameter exp(e).

Value

See weibull1.

Note

This function is for use with the function multdrc.

Author(s)

Christian Ritz

See Also

Related functions are W1.4 and weibull1.

Examples


## Fitting a three-parameter Weibull model
model1 <- multdrc(ryegrass, fct = W1.3())
model1

rm(model1)


[Package drc version 1.1-0 Index]