Compositional (version 5.5)

MLE of the zero adjusted Dirichlet distribution: MLE of the zero adjusted Dirichlet distribution

Description

MLE of the zero adjusted Dirichlet distribution.

Usage

zad.est(y, tol = 1e-05)

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.

tol

A tolerance level to terminate the maximisation process.

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.

Details

A zero adjusted Dirichlet distribution is being fittd and its parameters are estimated.

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

# NOT RUN {
y <- as.matrix(iris[, 1:3])
y <- y / rowSums(y)
mod1 <- diri.nr(y)
y[sample(1:450, 15) ] <- 0
mod2 <- zad.est(y)
# }