dr4plEst: Private function to fit the 4PL model to dose-response data

In jtlandis/dr4pl.dev: Dose Response Data Analysis using the 4 Parameter Logistic (4pl) Model

Description

Private function that actually fits the 4PL model to data. If the Hill bounds are attained at the end of optimization processes, then an indicator of convergence failure so that dr4pl.default can look for a remedy for convergence failure.

Usage

dr4plEst(dose, response, init.parm, trend, method.init, method.optim,
  method.robust, use.Hessian, level, upperl = NULL, lowerl = NULL)

Arguments

dose	a numeric vector of dose levels
response	a numeric vector of responses
init.parm	a numeric vector of initial parameters of the 4PL model supplied by a user.
trend	Indicator of whether a dose-response curve is a decreasing θ[3]<0 or increasing curve θ[3]>0. The default is "auto" which indicates that the trend of the curve is automatically determined by data. The option "decreasing" will impose a restriction θ[3]<=0 while the option "increasing" will impose a restriction θ[3]>=0 in an optimization process.
method.init	Method of obtaining initial values of the parameters. Should be one of "logistic" for the logistic method or "Mead" for the Mead method. The default option is the Mead method.
method.optim	Method of optimization of the parameters. This argument is directly delivered to the constrOptim function provided in the "base" package of R.
method.robust	Parameter to select loss function for the robust estimation method to be used to fit a model. The argument NULL indicates the sum of squares loss, "absolute" indicates the absolute deviation loss, "Huber" indicates Huber's loss and "Tukey" indicates Tukey's biweight loss.
use.Hessian	Indicator of whether the Hessian matrix (TRUE) or the gradient vector is used in the Hill bounds.
level	Confidence level to be used in Hill bounds computation.
upperl	a numeric vector of length 4 to impose a upper limit on c(θ[1],θ[2],θ[3],θ[4]) estimates. For no upper bound limit on a theta value specify Inf
lowerl	a numeric vector of length 4 to impose a lower limit on c(θ[1],θ[2],θ[3],θ[4]) estimates. For no lower bound limit on a theta value specify Inf

Value

List of final parameter estimates, name of robust estimation, loss value and so on.

jtlandis/dr4pl.dev documentation built on May 25, 2019, 12:43 a.m.