Preamble

library("forecast")
library("rugarch")
Loading required package: methods
Loading required package: parallel

Attaching package: 'rugarch'
The following object is masked from 'package:stats':

    sigma

ARCH(1)

n <- 500
time <- 1:n

for (i in 1:5) {
    arch1.spec = ugarchspec(variance.model = list(garchOrder=c(1,0)), 
                        mean.model = list(armaOrder=c(0,0)),
                        fixed.pars=list(mu = 0, omega=0.25, alpha1=0.5))
    arch1.sim <- ugarchpath(arch1.spec, n.sim=n)
    arch1 <- drop(arch1.sim@path$seriesSim)
    arch1.int <- cumsum(arch1)

    par(mfrow=c(1,2))
    plot(time, arch1, col=2, type="l")
    plot(time, arch1.int, col=2, type="l")
}