nabla: Unscramble I polynomial

In tfarima: Transfer Function and ARIMA Models

Unscramble I polynomial

Description

nabla multiplies the I polynomials of an object of the um class.

Usage

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

nabla(x, ...)

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

Arguments

x	an object of class um.
i	integer. Omit this component model.
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$nabla.

Examples

um1 <- um(i = "(1 - B)(1 - B^12)")
nabla(um1)

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