diff --git a/DESCRIPTION b/DESCRIPTION
index f18959e..43489a5 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -51,8 +51,8 @@ Description: SEM Trees and SEM Forests -- an extension of model-based decision
 License: GPL-3
 Encoding: UTF-8
 LazyLoad: yes
-Version: 0.9.19
-Date: 2023-11-24
+Version: 0.9.20
+Date: 2024-03-14
 RoxygenNote: 7.2.3
 VignetteBuilder: knitr
 BugReports: https://github.com/brandmaier/semtree/issues
diff --git a/R/npar.R b/R/npar.R
new file mode 100644
index 0000000..88256b1
--- /dev/null
+++ b/R/npar.R
@@ -0,0 +1,12 @@
+npar <- function(x) {
+  if (is(x,"OpenMx") || is(x,"MxRAMModel")) {
+    stop("npar() not implemented yet")
+  } else if (is(x, "ctsemFit")) {
+    stop("npar() not implemented yet")
+  } else if (is(x,"lavaan")) {
+    pt <- parameterTable(x)
+    sum(pt$free!=0)
+  } else {
+    stop("npar() not implemented yet")
+  }
+}
\ No newline at end of file
diff --git a/R/semtree.R b/R/semtree.R
index 948cf7c..e4fc4a1 100644
--- a/R/semtree.R
+++ b/R/semtree.R
@@ -130,6 +130,14 @@ semtree <- function(model, data=NULL, control=NULL, constraints=NULL,
     if (checkControl(control)!=TRUE) {stop( "Unknown options in semtree.control object!");}
   }
   
+  #
+  
+  
+  # set min.bucket and min.N heuristically
+  if (is.null(control$min.bucket)) {
+    control$min.bucket = control$min.N / 2
+  }
+  
   if (control$method=="cv") {
     ui_stop("This method ceased to exist. Please see modern score-based tests.")
   }