# Coinertia analysis with identity matrices

### Description

Performs a co-inertia of the triplets *(Q_1,K_1,R_0)* and
*(Q_2,K_2,R_0)* with identity matrices *K_1, K_2, R_0*.

### Usage

1 | ```
coinertiaI(X, Y, fast = TRUE)
``` |

### Arguments

`X` |
Species matrix X. |

`Y` |
Species Matrix Y. |

`fast` |
If |

### Details

Argument `fast`

is used to return only the row scores of
`Y`

in function `permutest.coca`

, which speeds the
permutation test considerably.

### Value

If `fast = TRUE`

, a matrix of row scores for matrix
`Y`

(see `scores`

below). If
`fast = FALSE`

a list with the following components:

`weights ` |
A list with components |

`scores ` |
A list with components |

`lambda ` |
the Eigenvalues of the analysis (the square of the singular values from the SVD. |

`call ` |
the matched function call. |

### Note

This function is not meant to be called directly by the user. If
you wish to use it study the code in
`permutest.coca`

to see how it should be called.

### Author(s)

Original Matlab code by C.J.F. ter Braak and A.P. Schaffers. R port by Gavin L. Simpson.

### References

Doledec, S and Chessel, D. (1994) Co-inertia analysis: a method for
studying species-environment relationships. *Freshwater Biology*
**31**, 277–294.

### See Also

`coinertia`