Model Formulae for Multivariate Abundance Data

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

mvformula(x)
<!-- % \usage{formulaMva(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

Ulrike Naumann and David Warton <David.Warton@unsw.edu.au>.

Examples

require(graphics)

data(spider)
spiddat <- mvabund(spider$abund)
X=as.matrix(spider$x)

## Create a formula for multivariate abundance data:
foo <- mvformula( spiddat~X )
#> Error in eval(terms(x)[[2]]): object 'spiddat' not found

## Check whether foo is a mvformula:
is.mvformula(foo)
#> Error in is.mvformula(foo): object 'foo' not found

## Plot a mvformula:
plot(foo)
#> Error in plot(foo): object 'foo' not found