# randomizing a community phylogenetics matrix: '3x' of Hardy (2008)

### Description

`resamp.3x`

is used for resampling data within a community dataset

### Usage

1 | ```
resamp.3x(obj, level=0.1)
``` |

### Arguments

`obj` |
a community dataset in spacodiR format (see |

`level` |
a proportion specifying the extent of data shuffling |

### Details

A resampling procedure for a species-by-plots matrix, based on Gotelli swapping.
Shuffles abundances within species and for a pair of plots. The `level`

defines
the degree of sampling, with larger values dictating a higher level of reshuffling.
For instance, if `level = 0.1`

and the dataset involves 20 species and 20 plots,
a total of 40 (`0.1x20x20`

) Gotelli-like swaps are performed. The number of swaps is always rounded up such that at least one swap is performed (i.e., when `level=0`

).

### Value

A shuffled dataset

### Author(s)

Jonathan Eastman

### References

HARDY OJ. 2008. Testing the spatial phylogenetic structure of local communities: statistical performances of different null models and test statistics on a locally neutral community. Journal of Ecology 96:914-926.

GOTELLI NJ. 2000. Null model analysis of species co-occurrence patterns. Ecology 81:2606-2621.

### See Also

`spacodi.by.nodes`

for permutation tests of community diversity and additional randomization methods;
see `spacodi.calc`

for the main underlying function; `randomizeMatrix`

### Examples

1 2 3 4 5 6 | ```
data(sp.example)
attach(sp.example)
spl
# shuffle dataset
resamp.3x(obj=spl, level=0.2)
``` |