Nothing
## simple examples with offsets, to exercise methods etc.
library(lme4)
if (.Platform$OS.type != "windows") {
## generate a basic Gamma/random effects sim
set.seed(101)
d <- expand.grid(block=LETTERS[1:26],rep=1:100)
d$x <- runif(nrow(d)) ## sd=1
reff_f <- rnorm(length(levels(d$block)),sd=1)
## need intercept large enough to avoid negative values
d$eta0 <- 4+3*d$x ## version without random effects
d$eta <- d$eta0+reff_f[d$block]
## lmer() test:
d$mu <- d$eta
d$y <- rnorm(nrow(d),mean=d$mu,sd=1)
fm1 <- lmer(y~x+(1|block), data=d)
fm1off <- lmer(y~x+(1|block)+offset(3*x),data=d)
## check equality
stopifnot(all.equal(fixef(fm1)[2]-3,fixef(fm1off)[2]))
p0 <- predict(fm1)
p1 <- predict(fm1,newdata=d)
p2 <- predict(fm1off,newdata=d)
stopifnot(all.equal(p0,p1),
all.equal(p1,p2))
## glmer() test:
d$mu <- exp(d$eta)
d$y <- rpois(nrow(d),d$mu)
gm1 <- glmer(y~x+(1|block), data=d,family=poisson,
control=glmerControl(check.conv.grad="ignore"))
gm1off <- glmer(y~x+(1|block)+offset(3*x),data=d,family=poisson,
control=glmerControl(check.conv.grad="ignore"))
## check equality
stopifnot(all.equal(fixef(gm1)[2]-3,fixef(gm1off)[2],tolerance=3e-4))
p0 <- predict(gm1)
p1 <- predict(gm1,newdata=d)
p2 <- predict(gm1off,newdata=d)
stopifnot(all.equal(p0,p1),
all.equal(p1,p2))
## FIXME: should also test simulations
} ## skip on windows (for speed)
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