# mvformula: Model Formulae for Multivariate Abundance Data In mvabund: Statistical Methods for Analysing Multivariate Abundance Data

## Description

`mvformula` is a method to create an object of class `mvformula`
`as.mvformula` is a function to turn a formula into a `mvformula`
`is.mvformula` tests if its argument is a `mvformula` object. `mvformula` is a class of objects for which special-purpose plotting and regression functions have been written in the `mvabund-package`. The above are useful preliminary functions before analysing data using the special-purpose functions. These new functions were written specially for the analysis of multivariate abundance data in ecology, hence the title 'mvabund'.

## Usage

 ```1 2 3 4``` ```mvformula(x) as.mvformula(x) is.mvformula(x) ```

## Arguments

 `x` an R object.

## Details

`mvformula` is a method to create an object of class `mvformula` If the response of the resulting formula is not a `mvabund` object, a warning will be printed. `as.mvformula` is a function to turn a formula into a `mvformula` if the response in x is a data.frame or an unsuitable object the conversion will fail.

## Value

a formula mvabund for `mvformula` and `as.mvformula` a logical value indicating whether `x` is a `mvformula` object

## Author(s)

Ulrike Naumann and David Warton <[email protected]>.

`mvabund`. `manylm`.
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14``` ```require(graphics) data(spider) spiddat <- mvabund(spider\$abund) X <- spider\$x ## Create a formula for multivariate abundance data: foo <- mvformula( spiddat~X ) ## Check whether foo is a mvformula: is.mvformula(foo) ## Plot a mvformula: plot(foo) ```