ARMA and VARMA estimation

• acf — autocorrelation function
• arma2param — explodes a Varmax model for estimation uses
• arma_dv — Computes the partial derivatives in a VARMA model
• mak — centered moving average for a matrix
• makts — centered moving average for a time series
• maok — k-periods uncentered moving average for a matrix
• maokts — k-periods uncentered moving average for a time series
• pacf — Partial autocorrelation function
• theta2arm2 — transformation of VARMA estimate into the corresponding matrices
• theta2arma — transformation of VARMA model into its reduced form
• transf_roots — reverses roots lower than 1 in a L polynom
• varma — estimation of a (V)ARMA(X) model
• varmaf — forecasts from a VARMA model