diff --git a/jsprit-core/src/main/java/jsprit/core/util/ArrayUtils.java b/jsprit-core/src/main/java/jsprit/core/util/ArrayUtils.java
index 31e03ef5..e995448e 100644
--- a/jsprit-core/src/main/java/jsprit/core/util/ArrayUtils.java
+++ b/jsprit-core/src/main/java/jsprit/core/util/ArrayUtils.java
@@ -16,6 +16,7 @@
  ******************************************************************************/
 package jsprit.core.util;
 
+import java.util.Collection;
 import java.util.List;
 
 public class ArrayUtils {
@@ -25,5 +26,15 @@ public class ArrayUtils {
 		for(int i=0;i<list.size();i++) arr[i]=list.get(i);
 		return arr;
 	}
+
+	public static double[] toPrimitiveArray(Collection<Double> collection){
+		double[] arr = new double[collection.size()];
+		int i=0;
+		for(Double d : collection){
+			arr[i]=d;
+			i++;
+		}
+		return arr;
+	}
 	
 }