dr4pl-param {dr4pl}

Constructor for dr4pl theta parameter

Description

As of version 2.0.0, dr4pl will require the theta parameter to be made by this function. This is to ensure the user is explicit about what their parameter is, and what is being optimized.

Usage

dr4pl_theta(
  theta_1 = NA,
  theta_2 = NA,
  theta_3 = NA,
  theta_4 = NA,
  isLog10 = FALSE
)

ParmToLog(x)

## S3 method for class 'dr4pl_theta'
ParmToLog(x)

## S3 method for class 'dr4pl_log10'
ParmToLog(x)

LogToParm(x)

## S3 method for class 'dr4pl_theta'
LogToParm(x)

## S3 method for class 'dr4pl_log10'
LogToParm(x)

Arguments

theta_1

Numeric. The upper asymptote of the 4pl model.

theta_2

Numeric. The value where Response is half way between the upper and lower asymptotes. This parameter is other wise known as IC50/EC50.

theta_3

Numeric. The slope of the 4pl model. When 'theta_3>0' the curve increases, and when 'theta_3<0', the curve decreases.

theta_4

Numeric. The lower asymptote of the 4pl model.

isLog10

Logical value indicating if the second parameter is on the log10 scale. The default, FALSE, informs dr4pl that the value passed to the 'theta_2' argument is on the linear scale. TRUE will indicate that 'theta_2' has already been transformed with log10. This ensures that the parameters are handled properly later on.

x

a dr4pl_param object

Details

The function 'dr4pl_theta' is a constructor function for the end user. While the default values for 'theta_1', 'theta_2', 'theta_3', 'theta_4' are 'NA', certain functions of 'dr4pl' will not allow 'NA' values. When 'dr4pl_theta' is used with the 'init.parm' argument of [dr4pl], then values with 'NA' will be estimated, and those specified, will be set as the initial parameter prior to optimization. If 'dr4pl_theta' is the object of S3 dispatch, then no NA values are allowed. However if the object if dispatch is a 'dr4pl' object, and 'dr4pl_theta' is passed into the function as an additional object such as in [X], [Y], then parameter non-NA values will be replaced in the appropriate dr4pl parameter estimates for the purpose of said function.

Value

an object of class '"dr4pl_param"'