Basic multistart method for saem.mmkin objects

1 files changed, 23 insertions, 3 deletions

diff --git a/R/multistart.R b/R/multistart.R
index db482cc4..819fcc1b 100644
--- a/R/multistart.R
+++ b/R/multistart.R
@@ -7,18 +7,38 @@
 #' inspired by the article on practical identifiabiliy in the frame of nonlinear
 #' mixed-effects models by Duchesne et al (2021).
 #'
+#' Currently, parallel execution of the fits is only supported using
+#' [parallel::mclapply], i.e. not available on Windows.
+#'
+#' @param object The fit object to work with
+#' @param n How many different combinations of starting parameters should be
+#' used?
+#' @param cores How many fits should be run in parallel?
+#' @param \dots Passed to the update function.
+#' @return A list of [saem.mmkin] objects, with class attributes
+#' 'multistart.saem.mmkin' and 'multistart'.
+#'
 #' @references Duchesne R, Guillemin A, Gandrillon O, Crauste F. Practical
 #' identifiability in the frame of nonlinear mixed effects models: the example
 #' of the in vitro erythropoiesis. BMC Bioinformatics. 2021 Oct 4;22(1):478.
 #' doi: 10.1186/s12859-021-04373-4.
 #' @export
-multistart <- function(object, n = 50, ...)
+multistart <- function(object, n = 50, cores = 1, ...)
 {
   UseMethod("multistart", object)
 }
 
 #' @rdname multistart
 #' @export
-multistart.saem.mmkin <- function(object, n = 50, ...) {
-  
+multistart.saem.mmkin <- function(object, n = 50, cores = 1, ...) {
+  start_parms <- apply(
+    parms(object$mmkin, errparms = FALSE), 1,
+      function(x) stats::runif(n, min(x), max(x))
+  )
+
+  res <- parallel::mclapply(1:n, function(x) {
+    update(object, degparms_start = start_parms[x], ...)
+  }, mc.cores = cores)
+  class(res) <- c("multistart.saem.mmkin", "multistart")
+  return(res)
 }