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forecast {forecast}

Forecasting time series
Package: 
forecast
Version: 
5.1

Description

forecast is a generic function for forecasting from time series or time series models. The function invokes particular methods which depend on the class of the first argument.

For example, the function forecast.Arima makes forecasts based on the results produced by arima.

The function forecast.ts makes forecasts using ets models (if the data are non-seasonal or the seasonal period is 12 or less) or stlf (if the seasonal period is 13 or more).

Usage

forecast(object,...)
 
## S3 method for class 'ts':
forecast((object, h = ifelse(frequency(object) > 1, 2 * frequency(object), 10) , 
         level=c(80,95), fan=FALSE, robust = FALSE, lambda = NULL, ...))

Arguments

object
a time series or time series model for which forecasts are required
h
Number of periods for forecasting
level
Confidence level for prediction intervals.
fan
If TRUE, level is set to seq(50,99,by=1). This is suitable for fan plots.
robust
If TRUE, the function is robust to missing values and outliers in object. This argument is only valid when object is of class ts.
lambda
Box-Cox transformation parameter.
...
Additional arguments affecting the forecasts produced. forecast.ts passes these to forecast.ets or stlf depending on the frequency of the time series.

Values

An object of class "forecast".

The function summary is used to obtain and print a summary of the results, while the function plot produces a plot of the forecasts and prediction intervals.

The generic accessors functions fitted.values and residuals extract various useful features of the value returned by forecast$model.

An object of class "forecast" is a list usually containing at least the following elements:

model
A list containing information about the fitted model
method
The name of the forecasting method as a character string
mean
Point forecasts as a time series
lower
Lower limits for prediction intervals
upper
Upper limits for prediction intervals
level
The confidence values associated with the prediction intervals
x
The original time series (either object itself or the time series used to create the model stored as object).
residuals
Residuals from the fitted model. For models with additive errors, the residuals will be x minus the fitted values.
fitted
Fitted values (one-step forecasts)

See Also

Other functions which return objects of class "forecast" are forecast.ets, forecast.Arima, forecast.HoltWinters, forecast.StructTS, meanf, rwf, splinef, thetaf, croston, ses, holt, hw.

Author(s)

Rob J Hyndman

Documentation reproduced from package forecast, version 5.1. License: GPL (>= 2)