MLE of the zero adjusted Dirichlet distribution {Compositional} | R Documentation |
MLE of the zero adjusted Dirichlet distribution
Description
MLE of the zero adjusted Dirichlet distribution.
Usage
zad.est(y)
Arguments
y |
A matrix with the compositional data (dependent variable). The number of observations (vectors) with no zero values should be more than the columns of the predictor variables. Otherwise, the initial values will not be calculated. |
Details
A zero adjusted Dirichlet distribution is being fittd and its parameters are estimated.
Value
A list including:
loglik |
The value of the log-likelihood. |
phi |
The precision parameter. If covariates are linked with it (function "diri.reg2"), this will be a vector. |
mu |
The mean vector of the distribution. |
runtime |
The time required by the regression. |
Author(s)
Michail Tsagris.
R implementation and documentation: Michail Tsagris mtsagris@uoc.gr.
References
Tsagris M. and Stewart C. (2018). A Dirichlet regression model for compositional data with zeros. Lobachevskii Journal of Mathematics,39(3): 398–412.
Preprint available from https://arxiv.org/pdf/1410.5011.pdf
See Also
zadr, diri.nr, zilogitnorm.est, zeroreplace
Examples
y <- as.matrix(iris[, 1:3])
y <- y / rowSums(y)
mod1 <- diri.nr(y)
y[sample(1:450, 15) ] <- 0
mod2 <- zad.est(y)