phi function

Unscramble AR polynomial

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

phi(um)

## S3 method for class 'um'
phi(um)

Arguments

• um: an object of class um.

Returns

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)