R: Methods for formulafn Functions

FormulaMethods {rmutil} | 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

### See Also

`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[1]+p[2]*x1)
    covariates(fn3)
    formula(fn3)
    model(fn3)
    parameters(fn3)

[Package rmutil version 1.1.3 Index]