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-rw-r--r--R/estpoly.R21
1 files changed, 18 insertions, 3 deletions
diff --git a/R/estpoly.R b/R/estpoly.R
index 96add69..7d85408 100644
--- a/R/estpoly.R
+++ b/R/estpoly.R
@@ -383,10 +383,25 @@ oe <- function(x,order=c(1,1,0),options=optimOptions()){
#' @details
#' SISO BJ models are of the form
#' \deqn{
-#' y[k] + f_1 y[k-1] + \ldots + f_{nf} y[k-nf] = b_{nk} u[k-nk] +
-#' \ldots + b_{nk+nb} u[k-nk-nb] + f_{1} e[k-1] + \ldots f_{nf} e[k-nf]
-#' + e[k]
+#' y[k] = \frac{B(q^{-1})}{F(q^{-1})}u[k-nk] +
+#' \frac{C(q^{-1})}{D(q^{-1})} e[k]
+#' }
+#' The orders of Box-Jenkins model are defined as follows:
+#' \deqn{
+#' B(q^{-1}) = b_1 + b_2q^{-1} + \ldots + b_{nb} q^{-nb+1}
+#' }
+#'
+#' \deqn{
+#' C(q^{-1}) = 1 + c_1q^{-1} + \ldots + c_{nc} q^{-nc}
+#' }
+#'
+#' \deqn{
+#' D(q^{-1}) = 1 + d_1q^{-1} + \ldots + d_{nd} q^{-nd}
#' }
+#' \deqn{
+#' F(q^{-1}) = 1 + f_1q^{-1} + \ldots + f_{nf} q^{-nf}
+#' }
+#'
#' The function estimates the coefficients using non-linear least squares
#' (Levenberg-Marquardt Algorithm)
#' \\