# Permutation of group membership for a single candidate partition

### Description

Randomizes group assignments for all permutations based on ranked values of the environmental gradient, then calls the appropriate matrix-based IndVal function.

### Usage

1 | ```
permiv(grp, spp, ivTot = ivTot, nPerm = 250)
``` |

### Arguments

`grp` |
A vector of binary (0,1) assignments indicating group membership for a single partition of nrows in 'spp' according to a ranks of an environmental variable. |

`spp` |
A site-by-taxon matrix of taxa counts at each sampling location. |

`ivTot` |
A logical indicating whether IndVal scores should be calculated using total relative abundance or the mean relative abundace originally proposed by Dufrene and Legendre (1997). |

`nPerm` |
The number of permutations to be performed. |

### Details

This function handles the randomization portion of the permutation procedure, and then serves as a wrapper for 'indvalp' and 'indvalps' (depending on the value of 'ivTot'), which estimate change-point distributions across all permutations. The output is the same as 'indvalp' and 'indvalps' because the function simply passes their products on.

### Value

A matrix (ivmax) of IndVal maxima with nrow equal to the number of permutations and ncol equal to the number of taxa in 'spp'.

### Author(s)

M. Baker and R. King

### References

Dufrene, M. and P. Legendre. 1997. Species assemblages and indicator species: the need for a flexible asymmetrical approach. Ecol. Mon. 67:345-366.

Baker, ME and RS King. 2010. A new method for detecting and interpreting biodiversity and ecological community thresholds. Methods in Ecology and Evolution 1(1): 25:37.

### See Also

`indvalp`

, `indvalps`

,
`getivz`

, `b.getivz`