mvformula: Model Formulae for 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

mvformula(x)

as.mvformula(x)
is.mvformula(x)

Arguments

an R object.

Value

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

Examples

Run this code

# NOT RUN {
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)

# }