Estimation of the value of alpha in the folded model | R Documentation |

Estimation of the value of *α* in the folded model.

a.est(x)

`x` |
A matrix with the compositional data. No zero vaues are allowed. |

This is a function for choosing or estimating the value of *α*
in the folded model (Tsagris and Stewart, 2020).

A list including:

`runtime` |
The runtime of the algorithm. |

`best` |
The estimated optimal |

`loglik` |
The maximimised log-likelihood of the folded model. |

`p` |
The estimated probability inside the simplex of the folded model. |

`mu` |
The estimated mean vector of the folded model. |

`su` |
The estimated covariance matrix of the folded model. |

Michail Tsagris.

R implementation and documentation: Michail Tsagris mtsagris@uoc.gr.

Tsagris M. and Stewart C. (2020). A folded model for compositional data analysis. Australian and New Zealand Journal of Statistics, 62(2): 249-277. https://arxiv.org/pdf/1802.07330.pdf

Tsagris M.T., Preston S. and Wood A.T.A. (2011). A data-based power transformation for compositional data. In Proceedings of the 4th Compositional Data Analysis Workshop, Girona, Spain. https://arxiv.org/pdf/1106.1451.pdf

```
alfa.profile, alfa, alfainv, alpha.mle
```

x <- as.matrix(iris[, 1:4]) x <- x / rowSums(x) alfa.tune(x) a.est(x)

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