SimGLP: Simulate GLP given innovations

Description Usage Arguments Details Value Author(s) See Also Examples

Description

Simulates a General Linear Time Series that can have nonGaussian innovations. It uses the FFT so it is O(N log(N)) flops where N=length(a) and N is assumed to be a power of 2. The R function convolve is used which implements the FFT.

Usage

1
SimGLP(psi, a)

Arguments

psi

vector, length Q, of MA coefficients starting with 1.

a

vector, length Q+n, of innovations, where n is the length of time series to be generated.

Details

z_t = ∑_{k=0}^Q psi_k a_{t-k}

where t=1,…,n and the innovations $a_t, t=1-Q, ..., 0, 1, ..., n$ are given in the input vector a.

Since convolve uses the FFT this is faster than direct computation.

Value

vector of length n, where n=length(a)-length(psi)

Author(s)

A.I. McLeod

See Also

convolve, arima.sim

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
#Simulate an AR(1) process with parameter phi=0.8 of length n=100 with
#  innovations from a t-distribution with 5 df and plot it.
#
phi<-0.8
psi<-phi^(0:127)
n<-100
Q<-length(psi)-1
a<-rt(n+Q,5)
z<-SimGLP(psi,a)
z<-ts(z)
plot(z)

ltsa documentation built on May 2, 2019, 4:01 a.m.