Various Utility Functions
reverse.parm and reverse.exclude reverse the order of
variables in an interaction term.
formatCands creates new classes for lists containing candidate
models.
formulaShort prints a succinct formula from an unmarkedFit object.
reverse.parm(parm) reverse.exclude(exclude) formatCands(cand.set) formulaShort(mod, unmarked.type = NULL)
parm |
a parameter to be model-averaged, enclosed between quotes, as it appears in the output of some models. |
exclude |
a list of interaction or polynomial terms appearing in some models, as
they would appear in the call to the model function (i.e., |
cand.set |
a list storing each of the models in the candidate model set. |
mod |
an object storing the result of an |
unmarked.type |
a character string specifying the type of parameter in
an |
These utility functions are used internally by aictab,
modavg, and other related functions.
reverse.parm and reverse.exclude enable the user to
specify differently interaction terms (e.g., A:B, B:A)
across models for model averaging. These functions have been added to
avoid problems when users are not consistent in the specification of
interaction terms across models.
formatCands creates new classes for the list of candidate
models based on the contents of the list. These new classes are used
for method dispatch.
formulaShort is used by anovaOD.
reverse.parm returns all possible combinations of an interaction
term to identify models that include the parm of interest and
find the corresponding estimate and standard error in the model object.
reverse.exclude returns a list of all possible combinations of
exclude to identify models that should be excluded when
computing a model-averaged estimate.
formatCands adds a new class to the list of candidate
models based on the classes of the models.
formulaShort creates a character string for the formula related
to a given parameter type from an unmarkedFit object.
Marc J. Mazerolle
##a main effect
reverse.parm(parm = "Ageyoung") #does not return anything
##an interaction term as it might appear in the output
reverse.parm(parm = "Ageyoung:time") #returns the reverse
##exclude two interaction terms
reverse.exclude(exclude = list("Age*time", "A:B"))
##returns all combinations
reverse.exclude(exclude = list("Age:time", "A*B"))
##returns all combinations
##Mazerolle (2006) frog water loss example
data(dry.frog)
##setup a subset of models of Table 1
Cand.models <- list( )
Cand.models[[1]] <- lm(log_Mass_lost ~ Shade + Substrate +
cent_Initial_mass + Initial_mass2,
data = dry.frog)
Cand.models[[2]] <- lm(log_Mass_lost ~ Shade + Substrate +
cent_Initial_mass + Initial_mass2 +
Shade:Substrate, data = dry.frog)
Cand.models[[3]] <- lm(log_Mass_lost ~ cent_Initial_mass +
Initial_mass2, data = dry.frog)
formatCands(Cand.models)
## Not run:
require(unmarked)
data(bullfrog)
bfrog <- unmarkedFrameOccu(y = bullfrog[, c("V1", "V2", "V3", "V4")],
siteCovs = bullfrog[, 1:2])
fm1 <- occu(~ 1 ~ Reed.presence, data = bfrog)
formulaShort(fm1, unmarked.type = "state")
formulaShort(fm1, unmarked.type = "det")
## End(Not run)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.