# potthoff: Potthoff and Roy Growth Curve Model In swihart/growth: Multivariate Normal and Elliptically-Contoured Repeated Measurements Models

## Description

`potthoff` fits the Potthoff and Roy repeated measurements growth curve model with unstructured covariance matrix to completely balanced data.

## Usage

 ```1 2``` ```potthoff(response, x = NULL, ccov = NULL, times = NULL, torder = 0, orthogonal = TRUE) ```

## Arguments

 `response` A matrix or dataframe of response values. `x` A matrix defining the complete intersubject differences or a Wilkinson and Rogers formula that will create one. `ccov` A matrix of columns of the baseline covariates to be actually fitted, with one row per individual or a W&R formula that will create one. `times` A vector of unequally spaced times when they are the same for all individuals. Not necessary if equally spaced. `torder` Order of the polynomial in time to be fitted. If non-numeric, the full model in time is fitted. `orthogonal` If TRUE, uses orthogonal polynomials for time, otherwise only centres times at their mean.

## Value

A list of class potthoff is returned.

## Author(s)

J.K. Lindsey

`carma`, `elliptic`, `lm`.
 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```y <- matrix(rnorm(40),ncol=5) x <- gl(2,4) # full model with treatment effect potthoff(y, ~x, torder="f", ccov=~x) # no time trend with treatment effect potthoff(y, ~x, torder=0, ccov=~x) # quadratic time with treatment effect potthoff(y, ~x, torder=2, ccov=~x) # full model without treatment effect potthoff(y, ~x, torder="f") # linear time without treatment effect potthoff(y, ~x, torder=1) ```