sketch of xgboost-spark

chooseBestBooster shall be in Boosters

remove tracker.py

rename XGBoost

remove cross-validation

jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/IObjective.java

@@ -15,6 +15,7 @@
  */
 package ml.dmlc.xgboost4j;
 
+import java.io.Serializable;
 import java.util.List;
 
 /**
@@ -22,7 +23,7 @@ import java.util.List;
  *
  * @author hzx
  */
-public interface IObjective {
+public interface IObjective extends Serializable {
   /**
    * user define objective function, return gradient and second order gradient
    *

jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/XGBoost.java

@@ -143,7 +143,7 @@ public class XGBoost {
    * @return evaluation history
    * @throws XGBoostError native error
    */
-  public static String[] crossValiation(
+  public static String[] crossValidation(
       Map<String, Object> params,
       DMatrix data,
       int round,

jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/XGBoost.scala

@@ -35,7 +35,7 @@ object XGBoost {
     new ScalaBoosterImpl(xgboostInJava)
   }
 
-  def crossValiation(
+  def crossValidation(
       params: Map[String, AnyRef],
       data: DMatrix,
       round: Int,
@@ -43,7 +43,7 @@ object XGBoost {
       metrics: Array[String] = null,
       obj: ObjectiveTrait = null,
       eval: EvalTrait = null): Array[String] = {
-    JXGBoost.crossValiation(params.asJava, data.jDMatrix, round, nfold, metrics, obj, eval)
+    JXGBoost.crossValidation(params.asJava, data.jDMatrix, round, nfold, metrics, obj, eval)
   }
 
   def initBoostModel(params: Map[String, AnyRef], dMatrixs: Array[DMatrix]): Booster = {