Package 'glmmTMB'

Description

Methods have been written that allow glmmTMB objects to be used with several downstream packages that enable different forms of inference. For some methods (Anova and emmeans, but not effects at present), set the component argument to "cond" (conditional, the default), "zi" (zero-inflation) or "disp" (dispersion) in order to produce results for the corresponding part of a glmmTMB model. Support for emmeans also allows additional options component = "response" (response means taking both the cond and zi components into account), and component = "cmean" (mean of the [possibly truncated] conditional distribution).

In particular,

• car::Anova constructs type-II and type-III Anova tables for the fixed effect parameters of any component

• the emmeans package computes estimated marginal means (previously known as least-squares means) for the fixed effects of any component, or predictions with type = "response" or type = "component". Note: In hurdle models, component = "cmean" produces means of the truncated conditional distribution, while component = "cond", type = "response" produces means of the untruncated conditional distribution.

• the effects package computes graphical tabular effect displays (only for the fixed effects of the conditional component)

Usage

Anova.glmmTMB(
  mod,
  type = c("II", "III", 2, 3),
  test.statistic = c("Chisq", "F"),
  component = "cond",
  vcov. = vcov(mod)[[component]],
  singular.ok,
  include.rankdef.cols = FALSE,
  ...
)

Effect.glmmTMB(focal.predictors, mod, ...)

Arguments

Details

While the examples below are disabled for earlier versions of R, they may still work; it may be necessary to refer to private versions of methods, e.g. glmmTMB:::Anova.glmmTMB(model, ...).

Examples

warp.lm <- glmmTMB(breaks ~ wool * tension, data = warpbreaks)
salamander1 <- up2date(readRDS(system.file("example_files","salamander1.rds",package="glmmTMB")))
if (require(emmeans)) withAutoprint({
    emmeans(warp.lm, poly ~ tension | wool)
    emmeans(salamander1, ~ mined, type="response")  # conditional means
    emmeans(salamander1, ~ mined, component="cmean")     # same as above, but re-gridded
    emmeans(salamander1, ~ mined, component="zi", type="response")  # zero probabilities
    emmeans(salamander1, ~ mined, component="response")  # response means including both components
})
if (getRversion() >= "3.6.0") {
   if (require(car)) withAutoprint({
       Anova(warp.lm,type="III")
       Anova(salamander1)
       Anova(salamander1, component="zi")
   })
   if (require(effects)) withAutoprint({
       plot(allEffects(warp.lm))
       plot(allEffects(salamander1))
   })
}

Description

Get theta parameterisation of a covariance structure

Usage

as.theta.vcov(Sigma, corrs.only = FALSE)

Arguments

Value

the corresponding theta parameter vector

Description

Calculate confidence intervals

Usage

## S3 method for class 'glmmTMB'
confint(
  object,
  parm = NULL,
  level = 0.95,
  method = c("wald", "Wald", "profile", "uniroot"),
  component = c("all", "cond", "zi", "other"),
  estimate = TRUE,
  include_nonest = FALSE,
  parallel = c("no", "multicore", "snow"),
  ncpus = getOption("profile.ncpus", 1L),
  cl = NULL,
  full = FALSE,
  ...
)

Arguments

Details

Available methods are

"wald"

These intervals are based on the standard errors calculated for parameters on the scale of their internal parameterization depending on the family. Derived quantities such as standard deviation parameters and dispersion parameters are back-transformed. It follows that confidence intervals for these derived quantities are typically asymmetric.

"profile"

This method computes a likelihood profile for the specified parameter(s) using profile.glmmTMB; fits a spline function to each half of the profile; and inverts the function to find the specified confidence interval.

"uniroot"

This method uses the uniroot function to find critical values of one-dimensional profile functions for each specified parameter.

At present, "wald" returns confidence intervals for variance parameters on the standard deviation/correlation scale, while "profile" and "uniroot" report them on the underlying ("theta") scale: for each random effect, the first set of parameter values are standard deviations on the log scale, while remaining parameters represent correlations on the scaled Cholesky scale. For a random effects model with two elements (such as a random-slopes model, or a random effect of factor with two levels), there is a single correlation parameter $\theta$; the correlation is equal to $\rho = \theta/\sqrt{1+\theta^2}$. For random-effects terms with more than two elements, the mapping is more complicated: see https://github.com/glmmTMB/glmmTMB/blob/master/misc/glmmTMB_corcalcs.ipynb

Examples

data(sleepstudy, package="lme4")
model <- glmmTMB(Reaction ~ Days + (1|Subject), sleepstudy)
model2 <- glmmTMB(Reaction ~ Days + (1|Subject), sleepstudy,
    dispformula= ~I(Days>8))
confint(model)  ## Wald/delta-method CIs
confint(model,parm="theta_")  ## Wald/delta-method CIs
confint(model,parm=1,method="profile")

Description

EXPERIMENTAL. For a given model, this function attempts to isolate potential causes of convergence problems. It checks (1) whether there are any unusually large coefficients; (2) whether there are any unusually scaled predictor variables; (3) if the Hessian (curvature of the negative log-likelihood surface at the MLE) is positive definite (i.e., whether the MLE really represents an optimum). For each case it tries to isolate the particular parameters that are problematic.

Usage

diagnose(
  fit,
  eval_eps = 1e-05,
  evec_eps = 0.01,
  big_coef = 10,
  big_sd_log10 = 3,
  big_zstat = 5,
  check_coefs = TRUE,
  check_zstats = TRUE,
  check_hessian = TRUE,
  check_scales = TRUE,
  explain = TRUE
)

Arguments

Details

Problems in one category (e.g. complete separation) will generally also appear in "downstream" categories (e.g. non-positive-definite Hessians). Therefore, it is generally advisable to try to deal with problems in order, e.g. address problems with complete separation first, then re-run the diagnostics to see whether Hessian problems persist.

Value

a logical value based on whether anything questionable was found

Description

Probability functions for k-truncated Poisson and negative binomial distributions.

Usage

dtruncated_nbinom2(x, size, mu, k = 0, log = FALSE)

dtruncated_poisson(x, lambda, k = 0, log = FALSE)

dtruncated_nbinom1(x, phi, mu, k = 0, log = FALSE)

Arguments

Description

Extended version of the epil dataset of the MASS package. The three transformed variables Visit, Base, and Age used by Booth et al. (2003) have been added to epil.

Usage

epil2

Format

A data frame with 236 observations on the following 12 variables:

y

an integer vector.

trt

a factor with levels "placebo" and "progabide".

base

an integer vector.

age

an integer vector.

V4

an integer vector.

subject

an integer vector.

period

an integer vector.

lbase

a numeric vector.

lage

a numeric vector.

Visit

(rep(1:4,59) - 2.5) / 5.

Base

log(base/4).

Age

log(age).

References

Booth, J.G., G. Casella, H. Friedl, and J.P. Hobert. (2003) Negative binomial loglinear mixed models. Statistical Modelling 3, 179–191.

Examples

epil2$subject <- factor(epil2$subject)
op <- options(digits=3)
(fm <- glmmTMB(y ~ Base*trt + Age + Visit + (Visit|subject),
              data=epil2, family=nbinom2))
meths <- methods(class = class(fm))
if((Rv <- getRversion()) > "3.1.3") {
  funs <- attr(meths, "info")[, "generic"]
  funs <- setdiff(funs, "profile")  ## too slow! pkgdown is trying to run this??
  for(fun in funs[is.na(match(funs, "getME"))]) {
        cat(sprintf("%s:\n-----\n", fun))
        r <- tryCatch( get(fun)(fm), error=identity)
        if (inherits(r, "error")) cat("** Error:", r$message,"\n")
        else tryCatch( print(r) )
        cat(sprintf("---end{%s}--------------\n\n", fun))
  }
}
options(op)

Description

Most conditional distributions have only parameters governing their location (retrieved via predict) and scale (sigma). A few (e.g. Tweedie, Student t, ordered beta) are characterized by one or more additional parameters.

Usage

family_params(object)

Arguments

Value

a named numeric vector

Description

These functions (called internally by glmmTMB) perform the actual model optimization, after all of the appropriate structures have been set up (fitTMB), and finalize the model after optimization (finalizeTMB). It can be useful to run glmmTMB with doFit=FALSE, adjust the components as required, and then finish the fitting process with fitTMB (however, it is the user's responsibility to make sure that any modifications create an internally consistent final fitted object).

Usage

fitTMB(TMBStruc, doOptim = TRUE)

finalizeTMB(TMBStruc, obj, fit, h = NULL, data.tmb.old = NULL)

Arguments

Examples

## 1. regular (non-modular) model fit:
m0 <- glmmTMB(count ~ mined + (1|site),
             family=poisson, data=Salamanders)
## 2. the equivalent fit, done modularly:
##  a. 
m1 <- glmmTMB(count ~ mined + (1|site),
             family=poisson, data=Salamanders,
             doFit = FALSE)
## result is a list of elements (data to be passed to TMB,
## random effects structures, etc.) needed to fit the model
names(m1)
## b. The next step calls TMB to set up the automatic differentiation
## machinery
m2 <- fitTMB(m1, doOptim = FALSE)
## The result includes initial parameter values, objective function
## (fn), gradient function (gr), etc.
names(m2)
## Optionally, one could choose to 
## modify the components of m1$env$data at this point ...
## updating the TMB structure as follows may be necessary:
m2 <- with(m2$env,
               TMB::MakeADFun(data,
                               parameters,
                               map = map,
                               random = random,
                               silent = silent,
                               DLL = "glmmTMB"))
## c. Use the starting values, objective function, and gradient
## function set up in the previous step to do the nonlinear optimization
m3 <- with(m2, nlminb(par, objective = fn, gr = gr))
## the resulting object contains the fitted parameters, value of
## the objective function, information on convergence, etc.
names(m3)
## d. The last step is to combine the information from the previous
## three steps into a \code{glmmTMB} object that is equivalent to
## the original fit
m4 <- finalizeTMB(m1, m2, m3)
m4$call$doFit <- NULL ## adjust 'call' element to match
all.equal(m0, m4)

Description

Extract Fixed Effects

Usage

## S3 method for class 'glmmTMB'
fixef(object, ...)

Arguments

Details

Extract fixed effects from a fitted glmmTMB model.

The print method for fixef.glmmTMB object only displays non-trivial components: in particular, the dispersion parameter estimate is not printed for models with a single (intercept) dispersion parameter (see examples)

Value

an object of class fixef.glmmTMB comprising a list of components (cond, zi, disp), each containing a (possibly zero-length) numeric vector of coefficients

Examples

data(sleepstudy, package = "lme4")
fm1 <- glmmTMB(Reaction ~ Days, sleepstudy)
(f1 <- fixef(fm1))
f1$cond
## show full coefficients, including empty z-i model and
## constant dispersion parameter
print(f1, print_trivials = TRUE)

Description

"format()" the 'VarCorr' matrix of the random effects – for print()ing and show()ing

Usage

formatVC(
  varcor,
  digits = max(3, getOption("digits") - 2),
  comp = "Std.Dev.",
  formatter = format,
  useScale = attr(varcor, "useSc"),
  ...
)

Arguments

Value

a character matrix of formatted VarCorr entries from varc.

Description

Extract the formula of a glmmTMB object

Usage

## S3 method for class 'glmmTMB'
formula(x, fixed.only = FALSE, component = c("cond", "zi", "disp"), ...)

Arguments

Description

translate vector of correlation parameters to correlation values

Usage

get_cor(theta, return_val = c("vec", "mat"))

put_cor(C, input_val = c("mat", "vec"))

Arguments

Details

These functions follow the definition at http://kaskr.github.io/adcomp/classdensity_1_1UNSTRUCTURED__CORR__t.html: if $L$ is the lower-triangular matrix with 1 on the diagonal and the correlation parameters in the lower triangle, then the correlation matrix is defined as $\Sigma = D^{-1/2} L L^\top D^{-1/2}$, where $D = \textrm{diag}(L L^\top)$. For a single correlation parameter $\theta_0$, this works out to $\rho = \theta_0/\sqrt{1+\theta_0^2}$. The get_cor function returns the elements of the lower triangle of the correlation matrix, in column-major order.

Value

a vector of correlation values (get_cor) or glmmTMB scaled-correlation parameters (put_cor)

Examples

th0 <- 0.5
stopifnot(all.equal(get_cor(th0),th0/sqrt(1+th0^2)))
set.seed(101)
C <- get_cor(rnorm(21), return_val = "mat")
## test: round-trip
stopifnot(all.equal(get_cor(put_cor(C), return_val = "mat"), C))

Description

List model options that glmmTMB knows about

Usage

getCapabilities(what = "all", check = FALSE)

Arguments

Value

if check==FALSE, returns a vector of the names (or a list of name vectors) of allowable entries; if check==TRUE, returns a logical vector of working families

Note

these are all the options that are defined internally; they have not necessarily all been implemented (FIXME!)

Description

Extract or Get Generalize Components from a Fitted Mixed Effects Model

Usage

## S3 method for class 'glmmTMB'
getME(
  object,
  name = c("X", "Xzi", "Z", "Zzi", "Xdisp", "theta", "beta", "b"),
  ...
)

Arguments

See Also

getME Get generic and re-export:

Description

Calculate random effect structure Calculates number of random effects, number of parameters, block size and number of blocks. Mostly for internal use.

Usage

getReStruc(reTrms, ss = NULL, aa = NULL, reXterms = NULL, fr = NULL)

Arguments

Value

a list

Examples

data(sleepstudy, package="lme4")
rt <- lme4::lFormula(Reaction~Days+(1|Subject)+(0+Days|Subject),
                    sleepstudy)$reTrms
rt2 <- lme4::lFormula(Reaction~Days+(Days|Subject),
                    sleepstudy)$reTrms
getReStruc(rt)
getReStruc(rt2)

Description

Create X and random effect terms from formula

Usage

getXReTrms(
  formula,
  mf,
  fr,
  ranOK = TRUE,
  type = "",
  contrasts,
  sparse = FALSE,
  old_smooths = NULL
)

Arguments

Value

a list composed of

Description

Fit a generalized linear mixed model (GLMM) using Template Model Builder (TMB).

Usage

glmmTMB(
  formula,
  data = NULL,
  family = gaussian(),
  ziformula = ~0,
  dispformula = ~1,
  weights = NULL,
  offset = NULL,
  contrasts = NULL,
  na.action,
  se = TRUE,
  verbose = FALSE,
  doFit = TRUE,
  control = glmmTMBControl(),
  REML = FALSE,
  start = NULL,
  map = NULL,
  sparseX = NULL,
  priors = NULL
)

Arguments

Details

• Binomial models with more than one trial (i.e., not binary/Bernoulli) can either be specified in the form prob ~ ..., weights = N, or in the more typical two-column matrix cbind(successes,failures)~... form.

• Behavior of REML=TRUE for Gaussian responses matches lme4::lmer. It may also be useful in some cases with non-Gaussian responses (Millar 2011). Simulations should be done first to verify.

• Because the df.residual method for glmmTMB currently counts the dispersion parameter, users should multiply this value by sqrt(nobs(fit) / (1+df.residual(fit))) when comparing with lm.

• Although models can be fitted without specifying a data argument, its use is strongly recommended; drawing model components from the global environment, or using df$var notation within model formulae, can lead to confusing (and sometimes hard-to-detect) errors.

• By default, vector-valued random effects are fitted with unstructured (general symmetric positive definite) variance-covariance matrices. Structured variance-covariance matrices can be specified in the form struc(terms|group), where struc is one of

  • diag (diagonal, heterogeneous variance)

  • ar1 (autoregressive order-1, homogeneous variance)

  • cs (compound symmetric, heterogeneous variance)

  • ou (* Ornstein-Uhlenbeck, homogeneous variance)

  • exp (* exponential autocorrelation)

  • gau (* Gaussian autocorrelation)

  • mat (* Matérn process correlation)

  • toep (* Toeplitz)

  • rr (reduced-rank/factor-analytic model)

  • homdiag (diagonal, homogeneous variance)

  • propto (* proportional to user-specified variance-covariance matrix)

  Structures marked with * are experimental/untested. See vignette("covstruct", package = "glmmTMB") for more information.

• For backward compatibility, the family argument can also be specified as a list comprising the name of the distribution and the link function (e.g. list(family="binomial", link="logit")). However, this alternative is now deprecated; it produces a warning and will be removed at some point in the future. Furthermore, certain capabilities such as Pearson residuals or predictions on the data scale will only be possible if components such as variance and linkfun are present, see family.

• Smooths taken from the mgcv package can be included in glmmTMB formulas using s; these terms will appear as additional components in both the fixed and the random-effects terms. This functionality is experimental for now. We recommend using REML=TRUE. See s for details of specifying smooths (and smooth2random and the appendix of Wood (2004) for technical details).

Note

For more information about the glmmTMB package, see Brooks et al. (2017) and the vignette(package="glmmTMB") collection. For the underlying TMB package that performs the model estimation, see Kristensen et al. (2016).

References

Brooks, M. E., Kristensen, K., van Benthem, K. J., Magnusson, A., Berg, C. W., Nielsen, A., Skaug, H. J., Mächler, M. and Bolker, B. M. (2017). glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. The R Journal, 9(2), 378–400.

Kristensen, K., Nielsen, A., Berg, C. W., Skaug, H. and Bell, B. (2016). TMB: Automatic differentiation and Laplace approximation. Journal of Statistical Software, 70, 1–21.

Millar, R. B. (2011). Maximum Likelihood Estimation and Inference: With Examples in R, SAS and ADMB. Wiley, New York. Wood, S. N. (2004) Stable and Efficient Multiple Smoothing Parameter Estimation for Generalized Additive Models. Journal of the American Statistical Association 99(467): 673–86. doi:10.1198/016214504000000980

Examples

(m1 <- glmmTMB(count ~ mined + (1|site),
  zi=~mined,
  family=poisson, data=Salamanders))
summary(m1)
##' ## Zero-inflated negative binomial model
(m2 <- glmmTMB(count ~ spp + mined + (1|site),
  zi=~spp + mined,
  family=nbinom2, data=Salamanders))

## Hurdle Poisson model
(m3 <- glmmTMB(count ~ spp + mined + (1|site),
  zi=~spp + mined,
  family=truncated_poisson, data=Salamanders))

## Binomial model
data(cbpp, package="lme4")
(bovine <- glmmTMB(cbind(incidence, size-incidence) ~ period + (1|herd),
  family=binomial, data=cbpp))

## Dispersion model
sim1 <- function(nfac=40, nt=100, facsd=0.1, tsd=0.15, mu=0, residsd=1)
{
  dat <- expand.grid(fac=factor(letters[1:nfac]), t=1:nt)
  n <- nrow(dat)
  dat$REfac <- rnorm(nfac, sd=facsd)[dat$fac]
  dat$REt <- rnorm(nt, sd=tsd)[dat$t]
  dat$x <- rnorm(n, mean=mu, sd=residsd) + dat$REfac + dat$REt
  dat
}
set.seed(101)
d1 <- sim1(mu=100, residsd=10)
d2 <- sim1(mu=200, residsd=5)
d1$sd <- "ten"
d2$sd <- "five"
dat <- rbind(d1, d2)
m0 <- glmmTMB(x ~ sd + (1|t), dispformula=~sd, data=dat)
fixef(m0)$disp
c(log(5), log(10)-log(5)) # expected dispersion model coefficients


## Using 'map' to fix random-effects SD to 10
m1_map <- update(m1, map=list(theta=factor(NA)),
                 start=list(theta=log(10)))
VarCorr(m1_map)

## smooth terms
data("Nile")
ndat <- data.frame(time = c(time(Nile)), val = c(Nile))
sm1 <- glmmTMB(val ~ s(time), data = ndat,
               REML = TRUE, start = list(theta = 5))
plot(val ~ time, data = ndat)
lines(ndat$time, predict(sm1))

## reduced-rank model
m1_rr <- glmmTMB(abund ~ Species + rr(Species + 0|id, d = 1),
                              data = spider_long)

Description

Control parameters for glmmTMB optimization

Usage

glmmTMBControl(
  optCtrl = NULL,
  optArgs = list(),
  optimizer = nlminb,
  profile = FALSE,
  collect = FALSE,
  parallel = list(n = getOption("glmmTMB.cores", 1L), autopar =
    getOption("glmmTMB.autopar", NULL)),
  eigval_check = TRUE,
  zerodisp_val = log(.Machine$double.eps)/4,
  start_method = list(method = NULL, jitter.sd = 0),
  rank_check = c("adjust", "warning", "stop", "skip"),
  conv_check = c("warning", "skip")
)

Arguments

Details

By default, glmmTMB uses the nonlinear optimizer nlminb for parameter estimation. Users may sometimes need to adjust optimizer settings in order to get models to converge. For instance, the warning ‘iteration limit reached without convergence’ may be fixed by increasing the number of iterations using (e.g.)

glmmTMBControl(optCtrl=list(iter.max=1e3,eval.max=1e3)).

Setting profile=TRUE allows glmmTMB to use some special properties of the optimization problem in order to speed up estimation in cases with many fixed effects.

Control parameters may depend on the model specification. The value of the controls is evaluated inside an R object that is derived from the output of the mkTMBStruc function. For example, to specify that profile should be enabled if the model has more than 5 fixed-effect parameters, specify

profile=quote(length(parameters$beta)>=5)

The optimizer argument can be any optimization (minimizing) function, provided that:

• the first three arguments, in order, are the starting values, objective function, and gradient function;

• the function also takes a control argument;

• the function returns a list with elements (at least) par, objective, convergence (0 if convergence is successful) and message (glmmTMB automatically handles output from optim(), by renaming the value component to objective)

Examples

## fit with default (nlminb) and alternative (optim/BFGS) optimizer
m1 <- glmmTMB(count~ mined, family=poisson, data=Salamanders)
m1B <- update(m1, control=glmmTMBControl(optimizer=optim,
               optArgs=list(method="BFGS")))
## estimates are *nearly* identical:
all.equal(fixef(m1), fixef(m1B))

Description

see refit and isLMM for details

Usage

## S3 method for class 'glmmTMB'
isLMM(x, ...)

## S3 method for class 'glmmTMB'
refit(object, newresp, ...)

Arguments

Details

These methods are still somewhat experimental (check your results carefully!), but they should allow parametric bootstrapping. They work by copying and replacing the original response column in the data frame passed to glmmTMB, so they will only work properly if (1) the data frame is still available in the environment and (2) the response variable is specified as a single symbol (e.g. proportion or a two-column matrix constructed on the fly with cbind(). Untested with binomial models where the response is specified as a factor.

Examples

if (requireNamespace("lme4")) {
## Not run: 
   fm1 <- glmmTMB(count~mined+(1|spp),
                  ziformula=~mined,
                  data=Salamanders,
                  family=nbinom1)
   ## single parametric bootstrap step: refit with data simulated from original model
   fm1R <- refit(fm1, simulate(fm1)[[1]])
   ## the bootMer function from lme4 provides a wrapper for doing multiple refits
   ##   with a specified summary function
   b1 <- lme4::bootMer(fm1, FUN=function(x) fixef(x)$zi, nsim=20, .progress="txt")
   if (requireNamespace("boot")) {
      boot.ci(b1,type="perc")
    }
   ## can run in parallel: may need to set up cluster explicitly,
   ## use clusterEvalQ() to load packages on workers
   if (requireNamespace("parallel")) {
      cl <- parallel::makeCluster(2)
      parallel::clusterEvalQ(cl, library("lme4"))
      parallel::clusterEvalQ(cl, library("glmmTMB"))
      b2 <- lme4::bootMer(fm1, FUN = function(x) fixef(x)$cond,
              nsim = 10, ncpus = 2, cl = cl, parallel = "snow")
   }

## End(Not run)
}

Description

Set map values for theta to be fixed (NA) for propto

Usage

map.theta.propto(ReStruc, map)

Arguments

Value

the corresponding theta parameter vector

Description

Family functions for glmmTMB

Usage

nbinom2(link = "log")

nbinom1(link = "log")

nbinom12(link = "log")

compois(link = "log")

truncated_compois(link = "log")

genpois(link = "log")

truncated_genpois(link = "log")

truncated_poisson(link = "log")

truncated_nbinom2(link = "log")

truncated_nbinom1(link = "log")

beta_family(link = "logit")

betabinomial(link = "logit")

tweedie(link = "log")

skewnormal(link = "identity")

lognormal(link = "log")

ziGamma(link = "inverse")

t_family(link = "identity")

ordbeta(link = "logit")

bell(link = "log")

Arguments

Details

If specified, the dispersion model uses a log link. Denoting the variance as $V$, the dispersion parameter as $\phi=\exp(\eta)$ (where $\eta$ is the linear predictor from the dispersion model), and the predicted mean as $\mu$:

gaussian

(from base R): constant $V=\phi^2$

Gamma

(from base R) phi is the shape parameter. $V=\mu\phi$

ziGamma

a modified version of Gamma that skips checks for zero values, allowing it to be used to fit hurdle-Gamma models

nbinom2

Negative binomial distribution: quadratic parameterization (Hardin & Hilbe 2007). $V=\mu(1+\mu/\phi) = \mu+\mu^2/\phi$.

nbinom1

Negative binomial distribution: linear parameterization (Hardin & Hilbe 2007). $V=\mu(1+\phi)$. Note that the $phi$ parameter has opposite meanings in the nbinom1 and nbinom2 families. In nbinom1 overdispersion increases with increasing phi (the Poisson limit is phi=0); in nbinom2 overdispersion decreases with increasing phi (the Poisson limit is reached as phi goes to infinity).

nbinom12

Negative binomial distribution: mixed linear/quadratic, as in the DESeq2 package or as described by Lindén and Mäntyniemi (2011). $V=\mu(1+\phi+\mu/psi)$. (In Lindén and Mäntyniemi's parameterization, $\omega = \phi$ and $\theta=1/\psi$.) If a dispersion model is specified, it applies only to the linear (phi) term.

truncated_nbinom2

Zero-truncated version of nbinom2: variance expression from Shonkwiler 2016. Simulation code (for this and the other truncated count distributions) is taken from C. Geyer's functions in the aster package; the algorithms are described in this vignette.

compois

Conway-Maxwell Poisson distribution: parameterized with the exact mean (Huang 2017), which differs from the parameterization used in the COMPoissonReg package (Sellers & Shmueli 2010, Sellers & Lotze 2015). $V=\mu\phi$.

genpois

Generalized Poisson distribution (Consul & Famoye 1992). $V=\mu\exp(\eta)$. (Note that Consul & Famoye (1992) define $\phi$ differently.) Our implementation is taken from the HMMpa package, based on Joe and Zhu (2005) and implemented by Vitali Witowski.

beta

Beta distribution: parameterization of Ferrari and Cribari-Neto (2004) and the betareg package (Cribari-Neto and Zeileis 2010); $V=\mu(1-\mu)/(\phi+1)$

betabinomial

Beta-binomial distribution: parameterized according to Morris (1997). $V=\mu(1-\mu)(n(\phi+n)/(\phi+1))$

tweedie

Tweedie distribution: $V=\phi\mu^power$. The power parameter is restricted to the interval $1<power<2$, i.e. the compound Poisson-gamma distribution. Code taken from the tweedie package, written by Peter Dunn. The power parameter (designated psi in the list of parameters) uses the link function qlogis(psi-1.0); thus one can fix the power parameter to a specified value using start = list(psi = qlogis(fixed_power-1.0)), map = list(psi = factor(NA)).

t_family

Student-t distribution with adjustable scale and location parameters (also called a Pearson type VII distribution). The shape (degrees of freedom parameter) is fitted with a log link; it may be often be useful to fix the shape parameter using start = list(psi = log(fixed_df)), map = list(psi = factor(NA)).

ordbeta

Ordered beta regression from Kubinec (2022); fits continuous (e.g. proportion) data in the closed interval [0,1]. Unlike the implementation in the ordbeta package, this family will not automatically scale the data. If your response variable is defined on the closed interval [a,b], transform it to [0,1] via y_scaled <- (y-a)/(b-a).

lognormal

Log-normal, parameterized by the mean and standard deviation on the data scale

skewnormal

Skew-normal, parameterized by the mean, standard deviation, and shape (Azzalini & Capitanio, 2014); constant $V=\phi^2$

bell

Bell distribution (see Castellares et al 2018).

Value

returns a list with (at least) components

References

• Azzalini A & Capitanio A (2014). "The skew-normal and related families." Cambridge: Cambridge University Press.

• Castellares F, Ferrari SLP, & Lemonte AJ (2018) "On the Bell Distribution and Its Associated Regression Model for Count Data" Applied Mathematical Modelling 56: 172–85. doi:10.1016/j.apm.2017.12.014

• Consul PC & Famoye F (1992). "Generalized Poisson regression model." Communications in Statistics: Theory and Methods 21:89–109.

• Ferrari SLP, Cribari-Neto F (2004). "Beta Regression for Modelling Rates and Proportions." J. Appl. Stat. 31(7), 799-815.

• Hardin JW & Hilbe JM (2007). "Generalized linear models and extensions." Stata Press.

• Huang A (2017). "Mean-parametrized Conway–Maxwell–Poisson regression models for dispersed counts." Statistical Modelling 17(6), 1-22.

• Joe H & Zhu R (2005). "Generalized Poisson Distribution: The Property of Mixture of Poisson and Comparison with Negative Binomial Distribution." Biometrical Journal 47(2): 219–29. doi:10.1002/bimj.200410102.

• Lindén, A & Mäntyniemi S. (2011). "Using the Negative Binomial Distribution to Model Overdispersion in Ecological Count Data." Ecology 92 (7): 1414–21. doi:10.1890/10-1831.1.

• Morris W (1997). "Disentangling Effects of Induced Plant Defenses and Food Quantity on Herbivores by Fitting Nonlinear Models." American Naturalist 150:299-327.

• Kubinec R (2022). "Ordered Beta Regression: A Parsimonious, Well-Fitting Model for Continuous Data with Lower and Upper Bounds." Political Analysis. doi:10.1017/pan.2022.20.

• Sellers K & Lotze T (2015). "COMPoissonReg: Conway-Maxwell Poisson (COM-Poisson) Regression". R package version 0.3.5. https://CRAN.R-project.org/package=COMPoissonReg

• Sellers K & Shmueli G (2010) "A Flexible Regression Model for Count Data." Annals of Applied Statistics 4(2), 943–61. doi:10.1214/09-AOAS306.

• Shonkwiler, J. S. (2016). "Variance of the truncated negative binomial distribution." Journal of Econometrics 195(2), 209–210. doi:10.1016/j.jeconom.2016.09.002.

Description

Create a factor with numeric interpretable factor levels.

Usage

numFactor(x, ...)

parseNumLevels(levels)

Arguments

Details

Some glmmTMB covariance structures require extra information, such as temporal or spatial coordinates. numFactor allows to associate such extra information as part of a factor via the factor levels. The original numeric coordinates are recoverable without loss of precision using the function parseNumLevels. Factor levels are sorted coordinate wise from left to right: first coordinate is fastest running.

Value

Factor with specialized coding of levels.

Examples

## 1D example
numFactor(sample(1:5,20,TRUE))
## 2D example
coords <- cbind( sample(1:5,20,TRUE), sample(1:5,20,TRUE) )
(f <- numFactor(coords))
parseNumLevels(levels(f)) ## Sorted
## Used as part of a model.matrix
model.matrix( ~f )
## parseNumLevels( colnames(model.matrix( ~f )) )
## Error: 'Failed to parse numeric levels: (Intercept)'
parseNumLevels( colnames(model.matrix( ~ f-1 )) )

Description

Checks whether OpenMP has been successfully enabled for this installation of the package. (Use the parallel argument to glmmTMBControl, or set options(glmmTMB.cores=[value]), to specify that computations should be done in parallel.) To further trace OpenMP settings, use options(glmmTMB_openmp_debug = TRUE).

Usage

omp_check()

Value

TRUE or FALSE depending on availability of OpenMP,

See Also

benchmark, glmmTMBControl

Description

Begging by owl nestlings

Usage

data(Owls)

Format

The Owls data set is a data frame with 599 observations on the following variables:

Nest

a factor describing individual nest locations

FoodTreatment

(factor) food treatment: Deprived or Satiated

SexParent

(factor) sex of provisioning parent: Female or Male

ArrivalTime

a numeric vector

SiblingNegotiation

a numeric vector

BroodSize

brood size

NegPerChick

number of negotations per chick

Note

Access to data kindly provided by Alain Zuur

Source

Roulin, A. and L. Bersier (2007) Nestling barn owls beg more intensely in the presence of their mother than in the presence of their father. Animal Behaviour 74 1099–1106. doi:10.1016/j.anbehav.2007.01.027; http://www.highstat.com/Books/Book2/ZuurDataMixedModelling.zip

References

Zuur, A. F., E. N. Ieno, N. J. Walker, A. A. Saveliev, and G. M. Smith (2009) Mixed Effects Models and Extensions in Ecology with R; Springer.

Examples

data(Owls, package = "glmmTMB")
require("lattice")
bwplot(reorder(Nest,NegPerChick) ~ NegPerChick | FoodTreatment:SexParent,
       data=Owls)
dotplot(reorder(Nest,NegPerChick) ~ NegPerChick| FoodTreatment:SexParent,
        data=Owls)
## Not run: 
## Fit negative binomial model with "constant" Zero Inflation :
owls_nb1 <- glmmTMB(SiblingNegotiation ~ FoodTreatment*SexParent +
                                    (1|Nest)+offset(log(BroodSize)),
              family = nbinom1(), zi = ~1, data=Owls)
owls_nb1_bs <- update(owls_nb1,
                      . ~ . - offset(log(BroodSize)) + log(BroodSize))
fixef(owls_nb1_bs)

## End(Not run)

Description

prediction

Usage

## S3 method for class 'glmmTMB'
predict(
  object,
  newdata = NULL,
  newparams = NULL,
  se.fit = FALSE,
  cov.fit = FALSE,
  re.form = NULL,
  allow.new.levels = FALSE,
  type = c("link", "response", "conditional", "zprob", "zlink", "disp", "latent"),
  zitype = NULL,
  na.action = na.pass,
  fast = NULL,
  debug = FALSE,
  ...
)

Arguments

Details

• To compute population-level predictions for a given grouping variable (i.e., setting all random effects for that grouping variable to zero), set the grouping variable values to NA. Finer-scale control of conditioning (e.g. allowing variation among groups in intercepts but not slopes when predicting from a random-slopes model) is not currently possible.

• Prediction of new random effect levels is possible as long as the model specification (fixed effects and parameters) is kept constant. However, to ensure intentional usage, a warning is triggered if allow.new.levels=FALSE (the default).

• Prediction using "data-dependent bases" (variables whose scaling or transformation depends on the original data, e.g. poly, ns, or poly) should work properly; however, users are advised to check results extra-carefully when using such variables. Models with different versions of the same data-dependent basis type in different components (e.g. formula= y ~ poly(x,3), dispformula= ~poly(x,2)) will probably not produce correct predictions.

Examples

data(sleepstudy,package="lme4")
g0 <- glmmTMB(Reaction~Days+(Days|Subject),sleepstudy)
predict(g0, sleepstudy)
## Predict new Subject
nd <- sleepstudy[1,]
nd$Subject <- "new"
predict(g0, newdata=nd, allow.new.levels=TRUE)
## population-level prediction
nd_pop <- data.frame(Days=unique(sleepstudy$Days),
                     Subject=NA)
predict(g0, newdata=nd_pop)
## return latent variables (BLUPs/conditional modes/etc. ) with standard errors
##  (actually conditional standard deviations)
predict(g0, type = "latent", se.fit = TRUE)

Description

Printing The Variance and Correlation Parameters of a glmmTMB

Usage

## S3 method for class 'VarCorr.glmmTMB'
print(
  x,
  digits = max(3, getOption("digits") - 2),
  comp = "Std.Dev.",
  formatter = format,
  ...
)

Arguments

Description

(EXPERIMENTAL/subject to change)

Details

glmmTMB can accept prior specifications, for doing maximum a posteriori (MAP) estimation (or Hamiltonian MC with the tmbstan package), or (outside of a Bayesian framework) for the purposes of regularizing parameter estimates

The priors argument to glmmTMB must (if not NULL) be a data frame with columns

prior

character; the prior specification, e.g. "normal(0,2)"

class

the name of the underlying parameter vector on which to impose the prior ("fixef", "fixef_zi", "fixef_disp", "ranef", "ranef_zi", "psi")

coef

(optional) a string (if present) specifying the particular elements of the parameter vector to apply the prior to. coef should specify an integer parameter index, a column name from the fixed effect model matrix or a grouping variable for a random effect (the behaviour is currently undefined if there is more one than random effect term with the same grouping variable in a model ...); one can also append "_cor" or "_sd" to a random-effects class specification to denote the correlation parameters, or all of the standard deviation parameters, corresponding to a particular random effect term. If the class element is missing, or a particular element is blank, then all of the elements of the specified parameter vector use independent priors with the given specification. The exception is for the fixed-effect parameter vectors ("fixef", "fixef_zi", "fixef_disp"), where the intercept (if present) is not included; the prior on the intercept must be set explicitly.

'The available prior distributions are:

• "normal" (mean/sd parameterization)

• "t" (mean/sd/df)

• "cauchy" (location/scale)

• "gamma" (mean/shape); applied on the SD (not the log-SD) scale

• "lkj" (correlation) [WARNING, maybe buggy at present!]

The first three are typically used for fixed effect parameters; the fourth for standard deviation parameters; and the last for correlation structures. See the "priors" vignette for examples and further information.

Examples

data("sleepstudy", package = "lme4")
prior1 <- data.frame(prior = c("normal(250,3)","t(0,3,3)","gamma(10,1)"),
                     class = c("fixef", "fixef", "ranef_sd"),
                     coef = c("(Intercept)", "Days", "Subject"))
g1 <- glmmTMB(Reaction ~ 1 + Days + (1 + Days |Subject), sleepstudy)
update(g1, priors = prior1)
prior2 <- data.frame(prior = c("t(0,3,3)","gamma(10,1)"),
                     class = c("fixef", "ranef_sd"),
                     coef = c("", "Subject"))
update(g1, priors = prior2)
## no prior is set for the intercept in this case - see Details above
prior3 <- data.frame(prior = "t(0, 3, 3)",
                     class = "fixef")
update(g1, priors = prior3)

Description

Compute likelihood profiles for a fitted model

Usage

## S3 method for class 'glmmTMB'
profile(
  fitted,
  parm = NULL,
  level_max = 0.99,
  npts = 8,
  stepfac = 1/4,
  stderr = NULL,
  trace = FALSE,
  parallel = c("no", "multicore", "snow"),
  ncpus = getOption("profile.ncpus", 1L),
  cl = NULL,
  ...
)

## S3 method for class 'profile.glmmTMB'
confint(object, parm = NULL, level = 0.95, ...)

Arguments

Details

Fits natural splines separately to the points from each half of the profile for each specified parameter (i.e., values above and below the MLE), then finds the inverse functions to estimate the endpoints of the confidence interval

Value

An object of class profile.glmmTMB, which is also a data frame, with columns .par (parameter being profiled), .focal (value of focal parameter), value (negative log-likelihood).

Examples

## Not run: 
m1 <- glmmTMB(count~ mined + (1|site),
       zi=~mined, family=poisson, data=Salamanders)
salamander_prof1 <- profile(m1, parallel="multicore",
                            ncpus=2, trace=1)
## testing
salamander_prof1 <- profile(m1, trace=1,parm=1)
salamander_prof1M <- profile(m1, trace=1,parm=1, npts = 4)
salamander_prof2 <- profile(m1, parm="theta_")


## End(Not run)
salamander_prof1 <- readRDS(system.file("example_files","salamander_prof1.rds",package="glmmTMB"))
if (require("ggplot2")) {
    ggplot(salamander_prof1,aes(.focal,sqrt(value))) +
        geom_point() + geom_line()+
        facet_wrap(~.par,scale="free_x")+
    geom_hline(yintercept=1.96,linetype=2)
}
salamander_prof1 <- readRDS(system.file("example_files","salamander_prof1.rds",package="glmmTMB"))
confint(salamander_prof1)
confint(salamander_prof1,level=0.99)

Description

Extract random effects from a fitted glmmTMB model, both for the conditional model and zero inflation.

Usage

## S3 method for class 'glmmTMB'
ranef(object, condVar = TRUE, ...)

## S3 method for class 'ranef.glmmTMB'
as.data.frame(x, ...)

## S3 method for class 'glmmTMB'
coef(object, condVar = FALSE, ...)

Arguments

Value

• For ranef, an object of class ranef.glmmTMB with two components:

  cond

  a list of data frames, containing random effects for the conditional model.

  zi

  a list of data frames, containing random effects for the zero inflation.

  disp

  a list of data frames, containing random effects for the dispersion model.

  If condVar=TRUE, the individual list elements within the cond, zi, and disp components (corresponding to individual random effects terms) will have associated condVar attributes giving the conditional variances of the random effects values. These are in the form of three-dimensional arrays: see ranef.merMod for details. The only difference between the packages is that the attributes are called ‘postVar’ in lme4, vs. ‘condVar’ in glmmTMB.

• For coef.glmmTMB: a similar list, but containing the overall coefficient value for each level, i.e., the sum of the fixed effect estimate and the random effect value for that level. Conditional variances are not yet available as an option for coef.glmmTMB.

• For as.data.frame: a data frame with components

  component

  part of the model to which the random effects apply (conditional or zero-inflation)

  grpvar

  grouping variable

  term

  random-effects term (e.g., intercept or slope)

  grp

  group, or level of the grouping variable

  condval

  value of the conditional mode

  condsd

  conditional standard deviation

Note

When a model has no zero inflation, the ranef and coef print methods simplify the structure shown, by default. To show the full list structure, use print(ranef(model),simplify=FALSE) or the analogous code for coef. In all cases, the full list structure is used to access the data frames, see example.

See Also

fixef.glmmTMB.

Examples

if (requireNamespace("lme4")) {
   data(sleepstudy, package="lme4")
   model <- glmmTMB(Reaction ~ Days + (1|Subject), sleepstudy)
   rr <- ranef(model)
   print(rr, simplify=FALSE)
   ## extract Subject conditional modes for conditional model
   rr$cond$Subject
   as.data.frame(rr)
}

Description

The glmmTMB package depends on several upstream packages, which it uses in a way that depends heavily on their internal (binary) structure. Sometimes, therefore, installing an update to one of these packages will require that you re-install a binary-compatible version of glmmTMB, i.e. a version that has been compiled with the updated version of the upstream package.

• If you have development tools (compilers etc.) installed, you should be able to re-install a binary-compatible version of the package by running install.packages("glmmTMB", type="source"). If you want to install the development version of glmmTMB instead, you can use remotes::install_github("glmmTMB/glmmTMB/glmmTMB"). (On Windows, you can install development tools following the instructions at https://cran.r-project.org/bin/windows/Rtools/; on MacOS, see https://mac.r-project.org/tools/.)

• If you do not have development tools and can't/don't want to install them (and so can't install packages with compiled code from source), you have two choices:

  • revert the upstream package(s) to their previous binary version. For example, using the checkpoint package:

    ## load (installing if necessary) the checkpoint package
    while (!require("checkpoint")) install.packages("checkpoint")
    ## retrieve build date of installed version of glmmTMB
    bd <- as.character(asDateBuilt(
          packageDescription("glmmTMB",fields="Built")))
    oldrepo <- getOption("repos")
    use_mran_snapshot(bd) ## was setSnapshot() pre-checkpoint v1.0.0
    install.packages("TMB")
    options(repos=oldrepo) ## restore original repo
    

    A similar recipe (substituting Matrix for TMB and TMB for glmmTMB) can be used if you get warnings about an incompatibility between TMB and Matrix.

  • hope that the glmmTMB maintainers have posted a binary version of the package that works with your system; try installing it via install.packages("glmmTMB",repos="https://glmmTMB.github.io/glmmTMB/repos",type="binary") If this doesn't work, please file an issue (with full details about your operating system and R version) asking the maintainers to build and post an appropriate binary version of the package.

Description

Compute residuals for a glmmTMB object

Usage

## S3 method for class 'glmmTMB'
residuals(
  object,
  type = c("response", "pearson", "working", "deviance", "dunn-smyth"),
  re.form = NULL,
  ...
)

## S3 method for class 'glmmTMB'
deviance(object, ...)

Arguments

Details

• Residuals are computed based on predictions of type "response", i.e. equal to the conditional mean for non-zero-inflated models and to mu*(1-p) for zero-inflated models

• Computing deviance residuals depends on the implementation of the dev.resids function from the object's family component; at present this returns NA for most "exotic" families (i.e. deviance residuals are currently only implemented for families built into base R plus nbinom1, nbinom2). Deviance residuals are based on the conditional distributions only, i.e. ignoring zero-inflation components.

• Deviance is computed as the sum of squared deviance residuals, so is available only for the families listed in the bullet point above. See deviance.merMod for more details on the definition of the deviance for GLMMs.

Description

A data set containing counts of salamanders with site covariates and sampling covariates. Each of 23 sites was sampled 4 times. When using this data set, please cite Price et al. (2016) as well as the Dryad data package (Price et al. 2015).

Usage

data(Salamanders)

Format

A data frame with 644 observations on the following 10 variables:

site

name of a location where repeated samples were taken

mined

factor indicating whether the site was affected by mountain top removal coal mining

cover

amount of cover objects in the stream (scaled)

sample

repeated sample

DOP

Days since precipitation (scaled)

Wtemp

water temperature (scaled)

DOY

day of year (scaled)

spp

abbreviated species name, possibly also life stage

count

number of salamanders observed

References

Price SJ, Muncy BL, Bonner SJ, Drayer AN, Barton CD (2016) Effects of mountaintop removal mining and valley filling on the occupancy and abundance of stream salamanders. Journal of Applied Ecology 53 459–468. doi:10.1111/1365-2664.12585

Price SJ, Muncy BL, Bonner SJ, Drayer AN, Barton CD (2015) Data from: Effects of mountaintop removal mining and valley filling on the occupancy and abundance of stream salamanders. Dryad Digital Repository. doi:10.5061/dryad.5m8f6

Examples

require("glmmTMB")
data(Salamanders)

zipm3 = glmmTMB(count~spp * mined + (1|site), zi=~spp * mined, Salamanders, family="poisson")

Description

This modifies the TMB object in place (beware!) Ultimately this will allow terms to be a vector of term names, with a matching val vector to specify the behaviour for each term

Usage

set_simcodes(g, val = "zero", terms = "ALL")

Arguments

Description

For Gaussian models, sigma returns the value of the residual standard deviation; for other families, it returns the dispersion parameter, however it is defined for that particular family. See details for each family below.

Usage

## S3 method for class 'glmmTMB'
sigma(object, ...)

Arguments

Details

The value returned varies by family:

gaussian

returns the maximum likelihood estimate of the standard deviation (i.e., smaller than the results of sigma(lm(...)) by a factor of (n-1)/n)

nbinom1

returns a dispersion parameter (usually denoted $\alpha$ as in Hardin and Hilbe (2007)): such that the variance equals $\mu(1+\alpha)$.

nbinom2

returns a dispersion parameter (usually denoted $\theta$ or $k$); in contrast to most other families, larger $\theta$ corresponds to a lower variance which is $\mu(1+\mu/\theta)$.

Gamma

Internally, glmmTMB fits Gamma responses by fitting a mean and a shape parameter; sigma is estimated as (1/sqrt(shape)), which will typically be close (but not identical to) that estimated by stats:::sigma.default, which uses sqrt(deviance/df.residual)

beta

returns the value of $\phi$, where the conditional variance is $\mu(1-\mu)/(1+\phi)$ (i.e., increasing $\phi$ decreases the variance.) This parameterization follows Ferrari and Cribari-Neto (2004) (and the betareg package):

betabinomial

This family uses the same parameterization (governing the Beta distribution that underlies the binomial probabilities) as beta.

genpois

returns the index of dispersion $\phi^2$, where the variance is $\mu\phi^2$ (Consul & Famoye 1992)

compois

returns the value of $1/\nu$; when $\nu=1$, compois is equivalent to the Poisson distribution. There is no closed form equation for the variance, but it is approximately underdispersed when $1/\nu <1$ and approximately overdispersed when $1/\nu >1$. In this implementation, $\mu$ is exactly equal to the mean (Huang 2017), which differs from the COMPoissonReg package (Sellers & Lotze 2015).

tweedie

returns the value of $\phi$, where the variance is $\phi\mu^p$. The value of $p$ can be extracted using family_params

ordbeta

see details for beta

The most commonly used GLM families (binomial, poisson) have fixed dispersion parameters which are internally ignored.

References

• Consul PC, and Famoye F (1992). "Generalized Poisson regression model. Communications in Statistics: Theory and Methods" 21:89–109.

• Ferrari SLP, Cribari-Neto F (2004). "Beta Regression for Modelling Rates and Proportions." J. Appl. Stat. 31(7), 799-815.

• Hardin JW & Hilbe JM (2007). "Generalized linear models and extensions." Stata press.

• Huang A (2017). "Mean-parametrized Conway–Maxwell–Poisson regression models for dispersed counts. " Statistical Modelling 17(6), 1-22.

• Sellers K & Lotze T (2015). "COMPoissonReg: Conway-Maxwell Poisson (COM-Poisson) Regression". R package version 0.3.5. https://CRAN.R-project.org/package=COMPoissonReg

Description

See vignette("sim", package = "glmmTMB") for more details and examples, and vignette("covstruct", package = "glmmTMB") for more information on the parameterization of different covariance structures.

Usage

simulate_new(
  object,
  nsim = 1,
  seed = NULL,
  family = gaussian,
  newdata,
  newparams,
  ...,
  return_val = c("sim", "pars", "object")
)

Arguments

Examples

## use Salamanders data for structure/covariates
sim_count <- simulate_new(~ mined + (1|site),
             newdata = Salamanders,
             zi = ~ mined,
             family = nbinom2,
             newparams = list(beta = c(2, 1),
                         betazi = c(-0.5, 0.5), ## logit-linear model for zi
                         betadisp = log(2), ## log(NB dispersion)
                         theta = log(1)) ## log(among-site SD)
)
sim_obj <- simulate_new(~ mined + (1|site),
            return_val = "object",
             newdata = Salamanders,
             zi = ~ mined,
             family = nbinom2,
             newparams = list(beta = c(2, 1),
                         betazi = c(-0.5, 0.5), ## logit-linear model for zi
                         betad = log(2), ## log(NB dispersion)
                         theta = log(1)) ## log(among-site SD)
)
data("sleepstudy", package = "lme4")
sim_obj <- simulate_new(~ 1 + (1|Subject) + ar1(0 + factor(Days)|Subject),
             return_val = "pars",
             newdata = sleepstudy,
             family = gaussian,
             newparams = list(beta = c(280, 1),
                         betad = log(2), ## log(SD)
                         theta = log(c(2, 2, 1))),
)

Description

Simulate from a glmmTMB fitted model

Usage

## S3 method for class 'glmmTMB'
simulate(object, nsim = 1, seed = NULL, re.form = NULL, ...)

Arguments

Details

Random effects are also simulated from their estimated distribution. Currently, it is not possible to condition on estimated random effects.

Value

returns a list of vectors. The list has length nsim. Each simulated vector of observations is the same size as the vector of response variables in the original data set. In the binomial family case each simulation is a two-column matrix with success/failure.

Description

data from spider2 directory, CANOCO FORTRAN package, with trait variables added; taken from the mvabund package and converted to long form. Variables:

• soil.dry

• bare.sand

• fallen.leaves

• moss

• herb.layer

• reflection

• id

• Species

• abund

Usage

spider_long

Format

An object of class data.frame with 336 rows and 9 columns.

References

• ter Braak, C. J. F. and Smilauer, P. (1998) CANOCO reference manual and user's guide to CANOCO for Windows: software for canonical community ordination (version 4). Microcomputer Power, New York, New York, USA

• van der Aart, P. J. M., and Smeenk-Enserink, N. (1975) Correlations between distributions of hunting spiders (Lycosidae, Ctenidae) and environmental characteristics in a dune area. Netherlands Journal of Zoology 25, 1-45.

Description

Methods for extracting developer-level information from glmmTMB models

Usage

## S3 method for class 'glmmTMB'
terms(x, component = "cond", part = "fixed", ...)

## S3 method for class 'glmmTMB'
model.matrix(
  object,
  component = "cond",
  part = "fixed",
  include_rankdef = FALSE,
  ...
)

Arguments

Description

conditionally update glmmTMB object fitted with an old TMB version

Load data from system file, updating glmmTMB objects

Usage

up2date(oldfit, update_gauss_disp = FALSE)

gt_load(fn, verbose = FALSE, mustWork = FALSE, ...)

Arguments

Description

Calculate Variance-Covariance Matrix for a Fitted glmmTMB model

Usage

## S3 method for class 'glmmTMB'
vcov(object, full = FALSE, include_nonest = TRUE, ...)

Arguments

Value

By default (full==FALSE), a list of separate variance-covariance matrices for each model component (conditional, zero-inflation, dispersion). If full==TRUE, a single square variance-covariance matrix for all top-level model parameters (conditional, dispersion, and variance-covariance parameters)

Description

Extract weights from a glmmTMB object

Usage

## S3 method for class 'glmmTMB'
weights(object, type = "prior", ...)

Arguments

Details

At present only explicitly specified prior weights (i.e., weights specified in the weights argument) can be extracted from a fitted model.

• Unlike other GLM-type models such as glm or glmer, weights() does not currently return the total number of trials when binomial responses are specified as a two-column matrix.

• Since glmmTMB does not fit models via iteratively weighted least squares, working weights (see weights.glm) are unavailable.