dse (version 2004.10-1)

toARMA: Convert to an ARMA Model

Description

Convert a state space model to an ARMA representation. The state is eliminated by a method which uses an equivalence that can be demonstrated by the Cayley Hamilton theorem. It is not very parsimonious.

Usage

toARMA(model, ...)
    ## S3 method for class 'ARMA':
toARMA(model, ...)
    ## S3 method for class 'SS':
toARMA(model, fuzz=1e-10, ...)
    ## S3 method for class 'TSestModel':
toARMA(model, ...)

Arguments

model

An object of class TSmodel.

fuzz

Parameters closer than fuzz to one or zero are set to 1.0 or 0.0 respectively

...

arguments to be passed to other methods.

Value

• An object of class 'ARMA' 'TSmodel' containing an ARMA model.

concept

DSE

References

See, for example, M. Aoki(1990)State Space Modelling of Time Series. 2d ed. rev. and enl., Springer-Verlag Aoki and Havenner, Econometric Reviews v.10,No.1, 1991, p13.

See Also

toSS fixConstants

Examples

if(is.R()) data("eg1.DSE.data.diff", package="dse1")
model <- toSS(estVARXls(eg1.DSE.data.diff))
model <- toARMA(model)