Nothing
setGeneric("simulate", function(object, nsim=1, seed=NULL, ...) standardGeneric("simulate"))
setMethod("simulate", "mle2",
function(object, nsim=1, seed, newdata=NULL,
newparams=NULL, ...) {
if (!is.null(seed)) set.seed(seed)
if (!is.null(newparams)) {
object@fullcoef <- newparams
}
g <- gfun(object,newdata=newdata, nsim=nsim,op="simulate")
if (nsim>1) {
g <- matrix(g,ncol=nsim)
}
g
})
setGeneric("predict", function(object, ...) standardGeneric("predict"))
setMethod("predict", "mle2",
function(object,newdata=NULL,
location="mean",newparams=NULL, ...) {
if (!is.null(newparams)) {
object@fullcoef <- newparams
}
gfun(object,newdata=newdata,location=location,op="predict")
})
setGeneric("residuals", function(object, ...) standardGeneric("residuals"))
setMethod("residuals", "mle2",
function(object,
type=c("pearson","response"),
location="mean",
...) {
type <- match.arg(type)
location <- match.arg(location)
pred <- predict(object,location)
## not sure this will work ...
obs <- with(object@data,
get(gsub("~.+","",object@formula)))
res <- obs-pred
if (type=="response") return(res)
vars <- predict(object,location="variance")
return(res/sqrt(vars))
})
## general-purpose function for simulation and
## prediction (the hard part is evaluating the parameters etc.)
##
gfun <- function(object,newdata=NULL,location=c("mean","median","variance"),
nsim,
op=c("predict","simulate")) {
## notes: should operate on formula
## pull out call$formula (not character)
location <- match.arg(location)
form <- try(as.formula(object@call$minuslogl))
if (inherits(form, "try-error") ||
!inherits(form, "formula")) {
stop("can only use predict() if formula specified")
}
LHS <- form[[3]]
ddist <- as.character(LHS[[1]])
spref <- switch(op,predict="s",simulate="r")
sdist <- gsub("^d",spref,ddist)
arglist <- as.list(LHS)[-1]
if (!exists(sdist) || !is.function(get(sdist)))
stop("function ",sdist," does not exist")
## evaluate parameters
## evaluate sdist [ newdata > coef > data ]
## if (is.null(object@data)) {
## comb <- newdata
## } else {
## nmatch <- match(names(newdata),names(object@data))
## comb <- object@data
## comb[na.omit(nmatch)] <- newdata[!is.na(nmatch)]
## comb <- c(comb,newdata[is.na(nmatch)])
## }
## comb <- c(newdata,object@data)
## comb <- comb[!duplicated(names(comb))]
## comb <- comb[sapply(comb,length)>0]
## rvar <- strsplit(object@formula,"~")[[1]][1]
## comb <- comb[!names(comb)==rvar] ## remove response variable
parameters <- eval(object@call$parameters)
if (!is.null(parameters)) {
vars <- as.character(sapply(parameters,"[[",2))
models <- sapply(parameters,function(z) call.to.char(z[[3]]))
parameters <- parameters[models!="1"]
npars <- length(parameters)
if (npars==0) { ## no non-constant parameters
parameters <- mmats <- vpos <- NULL
} else {
mmats <- list()
vpos <- list()
for (i in seq(along=parameters)) {
vname <- vars[i]
p <- parameters[[i]]
p[[2]] <- NULL
mmat <- with(c(newdata,object@data),
model.matrix(p,data=environment()))
## c(as.list(newdata),as.list(object@data)))
pnames <- paste(vname,colnames(mmat),sep=".")
assign(vname,mmat %*% coef(object)[pnames])
}
}
}
arglist1 <- lapply(arglist,eval,envir=c(newdata,object@data,
as.list(coef(object))),
enclos=sys.frame(sys.nframe()))
## HACK: need a way to figure out how many data points there
## are, in the *absence* of an explicit data argument
## then replicate constant values to the full length
if (op=="simulate") {
if (length(object@data)==0)
stop("need explicit data argument for simulation")
ndata <- max(sapply(c(newdata,object@data),length)) ## ???
arglist1 <- c(arglist1,list(n=ndata*nsim))
}
vals <- with(as.list(coef(object)),do.call(sdist,arglist1))
if (op=="predict") return(vals[[location]]) else return(vals)
}
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