phi: Unscramble AR polynomial

In tfarima: Transfer Function and ARIMA Models

Unscramble AR polynomial

Description

phi multiplies the AR polynomials of an object of the um class.

Usage

## S3 method for class 'ucarima'
phi(x, i = NULL, ar = TRUE, lp = TRUE, ...)

phi(x, ...)

## S3 method for class 'um'
phi(x, ...)

Arguments

x	an object of class um.
i	integer. Omit this component model.
ar	logical. If TRUE, the common AR polynomial is included.
lp	logical indicating the type of return: lagpol object or numeric vector.
...	additional arguments.

Value

A numeric vector c(1, a1, ..., ad)

Note

This function returns the member variable um$phi.

Examples

um1 <- um(ar = "(1 - 0.8B)(1 - 0.5B)")
phi(um1)

tfarima documentation built on Nov. 5, 2025, 7:43 p.m.