## Usage

ra2(speciesData = matrix(rpois(80, 1), nrow = 10))

## Arguments

- speciesData
- a resource utilization matrix (rows = species, columns = discrete
resource states) filled with non-negative real numbers.

## Value

Returns a random utilization matrix with the same dimensions as the
input matrix.

## Description

Randomizes a numeric utilization matrix speciesData by
replacing all non-zero elements with a random uniform [0,1] value.

## Details

The resource utilization matrix (rows = species, columns = discrete
resource categories) may include zeroes, but no negative numbers or missing
values. Relative resource within a species is first calculated, so the rows
need not sum to 1.0.

## Note

This algorithm retains the number and position of zero states in the
original matrix. However, all non-zero values are again replaced by a random
[0,1] value, which tends to inflate niche breadths of the simulated
assemblage. Although the results are not as severe as for RA1, this
algorithm is still prone to Type I errors, and is not recommended for niche
overlap analysis.

## References

Kobayashi, S. 1991. Interspecific relations in forest floor
coleopteran assemblages: niche overlap and guild structure. Researches
in Population Ecology 33: 345-360.

Winemiller, K.O. and E.R. Pianka. 1990. Organization in natural
assemblages of desert lizards and tropical fishes. Ecological Monographs
60: 27-55.

## Examples

ranUtil <- ra2(speciesData=matrix(rpois(40,0.5),nrow=8))