Add the function 'get.psi' to compute the matrix-valued function

Add the function 'get.psi' to compute the matrix-valued function psi based on a given semi-Markov kernel 'q'

NAMESPACE

@@ -54,6 +54,7 @@ export(get.H)
 export(get.P)
 export(get.Py)
 export(get.f)
+export(get.psi)
 export(get.qy)
 export(getKernel)
 export(is.mm)

R/get.H.R

@@ -16,7 +16,7 @@
 }
 
 
-#' Function to compute the value of \eqn{H}
+#' Function to compute the value of the sojourn time cumulative distribution \eqn{H}
 #' 
 #' @description Function to compute the value of \eqn{H} (See equation (3.4) p.46).
 #' 

R/get.psi.R

@@ -0,0 +1,44 @@
+# Function to compute the value of \eqn{\psi}
+.get.psi <- function(q) {
+
+  k <- dim(q)[3] - 1
+
+  psi <- array(data = 0, dim = c(nrow(q), ncol(q), k + 1)) # (S, S, k + 1)
+  psi[, , 1] <- diag(x = 1, nrow = nrow(q), ncol = ncol(q)) # k = 0
+
+  for (j in 1:k) {
+
+    psi[, , j + 1] <-
+      -Reduce('+', lapply(
+        X = 0:(j - 1),
+        FUN = function(l)
+          psi[, , l + 1] %*% (-q[, , j - l + 1])
+      ))
+  }
+
+  return(psi)
+
+}
+
+#' Function to compute the value of the matrix-valued function \eqn{\psi}
+#' 
+#' @description Function to compute the value of \eqn{\psi}, the matrix-valued 
+#'   function (See equation (3.16) p.53).
+#' 
+#' @param q An array giving the values of the kernel for a giving time horizon 
+#'   \eqn{[0, \dots, k]} (This kernel `q` is the output of the method `getKernel` 
+#'   or `.get.qy`).
+#' @return An array giving the value of \eqn{\psi(k)} at each time between 0 
+#'   and `k`.
+#' 
+#' @export
+#' 
+get.psi <- function(q) {
+
+  .is.kernel(q)
+
+  psi <- .get.psi(q)
+
+  return(psi)
+
+}

R/smm.R

@@ -72,41 +72,6 @@ get.qy <- function(x, k, upstates = x$states) {
 }
 
 
-#' Method to compute the value of \eqn{\psi}
-#' 
-#' @description Method to compute the value of \eqn{\psi}
-#'   (See equation (3.16) p.53).
-#' 
-#' @param q An array giving the values of the kernel for a giving time horizon 
-#'   \eqn{[0, \dots, k]} (This kernel `q` is the output of the method `getKernel` 
-#'   or `.get.qy`).
-#' @return An array giving the value of \eqn{\psi(k)} at each time between 0 
-#'   and `k`.
-#' 
-#' @noRd
-#' 
-.get.psi <- function(q) {
-
-  k <- dim(q)[3] - 1
-
-  psi <- array(data = 0, dim = c(nrow(q), ncol(q), k + 1)) # (S, S, k + 1)
-  psi[, , 1] <- diag(x = 1, nrow = nrow(q), ncol = ncol(q)) # k = 0
-
-  for (j in 1:k) {
-
-    psi[, , j + 1] <-
-      -Reduce('+', lapply(
-        X = 0:(j - 1),
-        FUN = function(l)
-          psi[, , l + 1] %*% (-q[, , j - l + 1])
-      ))
-  }
-
-  return(psi)
-
-}
-
-
 # Method to compute the value of \eqn{P}
 .get.P <- function(x, k, states = x$states, var = FALSE, klim = 10000) {