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gets (version 0.9)

coef.arx: Extraction functions for 'arx' objects

Description

Extraction functions for objects of class 'arx'

Usage

"coef"(object, spec=NULL, ...) "fitted"(object, spec=NULL, ...) "logLik"(object, ...) "plot"(x, spec=NULL, col=c("red","blue"), lty=c("solid","solid"), lwd=c(1,1), ...) "predict"(object, spec=NULL, n.ahead=12, newmxreg=NULL, newvxreg=NULL, newindex=NULL, n.sim=1000, innov=NULL, return=TRUE, plot=TRUE, plot.options=list(), ...) "print"(x, signif.stars=FALSE, ...) "residuals"(object, std=FALSE, ...) "summary"(object, ...) "vcov"(object, spec=NULL, ...)

Arguments

object
an object of class 'arx'
x
an object of class 'arx'
spec
NULL, "mean", "variance" or, in some instances, "both". When NULL is a valid value, then it is automatically determined whether information pertaining to the mean or variance specification should be returned
signif.stars
logical. If TRUE, then P-values are additionally encoded visually, see printCoefmat
std
logical. If FALSE (default), then the mean residuals are returned. If TRUE, then the standardised residuals are returned
n.ahead
generate forecasts up to n steps ahead (the default is 12)
newmxreg
a matrix (n.ahead rows and NCOL(mxregs) columns) with the out-of-sample values of the mxreg regressors
newvxreg
a matrix (n.ahead rows and NCOL(vxregs) columns) with the out-of-sample values of the vxreg regressors
newindex
date-index for the zoo object returned by predict.arx
n.sim
integer, the number of bootstrap replications for the generation of the variance forecasts
innov
NULL (default) or a vector of length n.ahead * n.sim containing the standardised errors (i.e. zero mean, unit variance) to bootstrap from
return
logical. If TRUE (default), then the out-of-sample forecasts are returned
plot
logical. If TRUE (default), then the out-of-sample forecasts are plotted
plot.options
a list of options related to the plotting of forecasts, see 'Details'
col
colours of actual (default=blue) and fitted (default=red) lines
lty
types of actual (default=solid) and fitted (default=solid) lines
lwd
widths of actual (default=1) and fitted (default=1) lines
...
additional arguments

Value

Details

The plot.options argument is a list that can contain any of the following arguments:

keep: integer greater than zero (default is 10) that controls the number of in-sample actual values to plot fitted: If TRUE, then the fitted values as well as actual values are plotted in-sample. The default is FALSE errors.only: logical or NULL (the default). If TRUE, then only mean forecasts are plotted when spec is set to "both" legend.loc: character string (the default is "topleft"). Allows the location of the plot legend to be altered newmactual: numeric vector or NULL (default). Enables the plotting of actual values out-of-sample in addition to the forecasts

See Also

arx

Examples

Run this code
##simulate from an AR(1):
set.seed(123)
y <- arima.sim(list(ar=0.4), 40)

##simulate four independent Gaussian regressors:
xregs <- matrix(rnorm(4*40), 40, 4)

##estimate an AR(2) with intercept and four conditioning
##regressors in the mean, and log-ARCH(3) in the variance:
mymod <- arx(y, mc=TRUE, ar=1:2, mxreg=xregs, arch=1:3)

##print results:
print(mymod)

##plot the fitted vs. actual values, and the residuals:
plot(mymod)

##generate out-of-sample forecasts of the mean:
predict(mymod, newmxreg=matrix(0,12,4))

##print the entries of object 'mymod':
summary(mymod)

##extract coefficient estimates (automatically determined):
coef(mymod)

##extract mean coefficients only:
coef(mymod, spec="mean")

##extract log-variance coefficients only:
coef(mymod, spec="variance")

##extract all coefficient estimates:
coef(mymod, spec="both")

##extract log-likelihood:
logLik(mymod)

##extract variance-covariance matrix of mean equation:
vcov(mymod)

##extract variance-covariance matrix of log-variance equation:
vcov(mymod, spec="variance")

##extract and plot the fitted mean values (automatically determined):
mfit <- fitted(mymod)
plot(mfit)

##extract and plot the fitted variance values:
vfit <- fitted(mymod, spec="variance")
plot(vfit)

##extract and plot both the fitted mean and variance values:
vfit <- fitted(mymod, spec="both")
plot(vfit)

##extract and plot the fitted mean values:
vfit <- fitted(mymod, spec="mean")
plot(vfit)

##extract and plot residuals:
epshat <- residuals(mymod)
plot(epshat)

##extract and plot standardised residuals:
zhat <- residuals(mymod, std=TRUE)
plot(zhat)

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