# FormulaMethods: Methods for formulafn Functions In rmutil: Utilities for Nonlinear Regression and Repeated Measurements Models

 FormulaMethods R Documentation

## Methods for formulafn Functions

### Description

Methods for accessing the contents of a function created from formula produced by `finterp` or a function modified by `fnenvir`.

`covariates`: extract the names of the covariates.

`formula`: extract the formula used to produce the function (`finterp` only).

`model`: extract the model function or model matrix if W&R notation was used.

`parameters`: extract the names of the parameters.

### Usage

```## S3 method for class 'formulafn'
covariates(z, ...)
## S3 method for class 'formulafn'
formula(x, ...)
model(z, ...)
parameters(z, ...)
## S3 method for class 'formulafn'
print(x, ...)
```

### Arguments

 `x,z` A function of class, `formulafn`. `...` Arguments to other functions.

### Value

These methods extract information about functions of class, `formulafn`, created by `finterp` or `fnenvir`.

### Author(s)

J.K. Lindsey

`finterp`, `fnenvir`.

### Examples

```x1 <- rpois(20,2)
x2 <- rnorm(20)
#
# Wilkinson and Rogers formula with three parameters
fn1 <- finterp(~x1+x2)
fn1
covariates(fn1)
formula(fn1)
model(fn1)
parameters(fn1)
#
# nonlinear formula with unknowns
fn2 <- finterp(~exp(b0+b1*x1+b2*x2))
fn2
covariates(fn2)
formula(fn2)
model(fn2)
parameters(fn2)
#
# function transformed by fnenvir
fn3 <- fnenvir(function(p) p+p*x1)
covariates(fn3)
formula(fn3)
model(fn3)
parameters(fn3)
```

rmutil documentation built on Oct. 29, 2022, 1:08 a.m.