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Represents a bivariate irregular autoregressive (BiAR) time series model. This class extends the `multidata` class and provides additional properties for modeling, forecasting, and interpolation of bivariate time series data.

Usage

BiAR(
  times = integer(0),
  series = integer(0),
  series_esd = integer(0),
  series_names = character(0),
  fitted_values = integer(0),
  loglik = integer(0),
  kalmanlik = integer(0),
  coef = c(0.8, 0),
  tAhead = 1,
  rho = 0,
  forecast = integer(0),
  interpolated_values = integer(0),
  interpolated_times = integer(0),
  interpolated_series = integer(0),
  zero_mean = TRUE,
  standardized = TRUE
)

Arguments

times

A numeric vector representing the time points.

series

A numeric matrix or vector representing the values of the time series.

series_esd

A numeric matrix or vector representing the error standard deviations of the time series.

series_names

An optional character vector representing the name of the series.

fitted_values

A numeric vector containing the fitted values from the model.

loglik

A numeric value representing the log-likelihood of the model.

kalmanlik

A numeric value representing the Kalman likelihood of the model.

coef

A numeric vector containing the estimated coefficients of the model.

tAhead

A numeric value specifying the forecast horizon (default: 1).

rho

A numeric vector containing the estimated coefficients of the model.

forecast

A numeric vector containing the forecasted values.

interpolated_values

A numeric vector containing the interpolated values.

interpolated_times

A numeric vector containing the times of the interpolated data points.

interpolated_series

A numeric vector containing the interpolated series.

zero_mean

A logical value indicating if the model assumes a zero-mean process (default: TRUE).

standardized

A logical value indicating if the model assumes a standardized process (default: TRUE).

Details

The `BiAR` class is designed to handle bivariate irregularly observed time series data using an autoregressive approach. It extends the `multidata` class to include additional properties for modeling bivariate time series.

Key features of the `BiAR` class include: - Support for bivariate time series data. - Forecasting and interpolation functionalities for irregular time points. - Assumptions of zero-mean and standardized processes, configurable by the user. - Estimation of model parameters and likelihoods, including Kalman likelihood.

Validation Rules

- `@times` must be a numeric vector without dimensions and strictly increasing. - `@series` must be a numeric matrix with two columns (bivariate) or be empty. - The number of rows in `@series` must match the length of `@times`. - `@series_esd`, if provided, must be a numeric matrix. Its dimensions must match those of `@series`, or it must have one row and the same number of columns. - If `@series_esd` contains NA values, they must correspond positionally to NA values in `@series`. - `@series_names`, if provided, must be a character vector with length equal to the number of columns in `@series`, and all names must be unique. - `@coef` must be a numeric vector of length 2, with each element strictly between -1 and 1. - `@tAhead` must be a strictly positive numeric scalar.

References

Elorrieta F, Eyheramendy S, Palma W, Ojeda C (2021). “A novel bivariate autoregressive model for predicting and forecasting irregularly observed time series.” Monthly Notices of the Royal Astronomical Society, 505(1), 1105-1116. ISSN 0035-8711, doi:10.1093/mnras/stab1216 , https://academic.oup.com/mnras/article-pdf/505/1/1105/38391762/stab1216.pdf.

Examples

o=iAR::utilities()
o<-gentime(o, n=200, distribution = "expmixture", lambda1 = 130, lambda2 = 6.5,p1 = 0.15, p2 = 0.85)
times=o@times
my_BiAR <- BiAR(times = times,coef = c(0.9, 0.3), rho = 0.9)

# Access properties
my_BiAR@coef
#> [1] 0.9 0.3