% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/regimen.R
\name{regimen}
\alias{regimen}
\title{Define a Regimen}
\usage{
regimen(what, when, how, ...)
}
\arguments{
\item{what}{a function determining whether patients' data would be
updated due to switching treatment. It takes \code{patient_data},
a data frame as argument, and returns a data frame of two columns
\code{patient_id} and \code{new_treatment}. Patients with \code{NA} in
\code{new_treatment} will be skipped.
The number of rows in the returned data frame may be smaller than the
number of patients in the input data frame. This indicates that some
patients' data will not be modifier.
Note that the returned object will be passed into function `how()`, which
is also provide by users. This argument can also be a
list of functions that will be executed sequentially. No default value.}

\item{when}{a function determining the time at which a patient switches
to another treatment regimen, measured from the time of enrollment.
It takes \code{patient_data}, a data frame as
argument, and returns a data frame of two columns \code{patient_id} and
\code{switch_time} (from \code{enroll_time}). No \code{NA} is allowed
in \code{switch_time} and the number of rows in the returned data frame
must equal the number of rows in \code{patient_data}, i.e., switching
time must be specified to every patients.
Note that the returned object will be passed into function `how()`, which
is also provided by users. This argument can also be a
list of functions that will be executed sequentially. No default value.}

\item{how}{a function updating patients' data after treatment switching.
Only modified columns and \code{patient_id} are returned. A cell will
be omitted if \code{NA}, meaning no change to that patient for the endpoint
or other variables. Equivalently, users can also fill the cell with
its original value. This argument can also be a list of functions that
will be executed sequentially. No default value.}

\item{...}{(optional) named arguments to be passed to one or more of
\code{what}, \code{when}, and \code{how}. Each argument is routed to every
function whose formal parameter list contains that name. All arguments must
be named, and every name must match at least one parameter of at least one
function in \code{what}, \code{when}, or \code{how}.}
}
\description{
Define a regimen of a trial. This is a user-friendly wrapper for
the class constructor \code{Regimens$new()}. Users who are not familiar with
the concept of classes may consider using this wrapper directly.

A regimen defines the rules to select patients who
switch treatments, to determine the time of switching, and to update patients'
endpoint data.
}
