spaMM (version 2.4.35)

Poisson: Family function for GLMs and mixed models with Poisson and zero-truncated Poisson response.

Description

Poisson (with a capital P) is a family that specifies the information required to fit a Poisson generalized linear model. Differs from the base version stats::poisson only in that it handles the zero-truncated variant, which can be specified either as Tpoisson(<link>) or as Poisson(<link>, trunc = 0L).

Usage

Poisson(link = "log", trunc = -1L)
Tpoisson(link="log")

Arguments

link

log, sqrt or identity link, specified by the sevaral available ways for GLM links (name, character string, one-element character vector, or object of class link-glm as returned by make.link).

trunc

Either 0L for zero-truncated distribution, or -1L for default untruncated dsitribution.

Value

A family object.

References

McCullagh, P. and Nelder, J.A. (1989) Generalized Linear Models, 2nd edition. London: Chapman & Hall.

Examples

# NOT RUN {
data("scotlip")
logLik(glm(I(1+cases)~1,family=Tpoisson(),data=scotlip))
logLik(fitme(I(1+cases)~1+(1|id),family=Tpoisson(),fixed=list(lambda=1e-8),data=scotlip))
# }