[JVM-PKG] Update JNI to include rabit codes

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

@@ -21,7 +21,7 @@ import org.apache.commons.logging.LogFactory;
 import java.io.IOException;
 
 /**
- * DMatrix for xgboost, similar to the python wrapper xgboost.py
+ * DMatrix for xgboost.
  *
  * @author hzx
  */

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

@@ -48,4 +48,5 @@ class JNIErrorHandle {
       throw new XGBoostError(XgboostJNI.XGBGetLastError());
     }
   }
+
 }

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

@@ -441,6 +441,27 @@ class JavaBoosterImpl implements Booster {
     return featureScore;
   }
 
+  /**
+   * Load the booster model from thread-local rabit checkpoint.
+   * This is only used in distributed training.
+   * @return the stored version number of the checkpoint.
+   * @throws XGBoostError
+   */
+  int loadRabitCheckpoint() throws XGBoostError {
+    int[] out = new int[1];
+    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterLoadRabitCheckpoint(this.handle, out));
+    return out[0];
+  }
+
+  /**
+   * Save the booster model into thread-local rabit checkpoint.
+   * This is only used in distributed training.
+   * @throws XGBoostError
+   */
+  void saveRabitCheckpoint() throws XGBoostError {
+    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterSaveRabitCheckpoint(this.handle));
+  }
+
   /**
    * transfer DMatrix array to handle array (used for native functions)
    *

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

@@ -0,0 +1,93 @@
+package ml.dmlc.xgboost4j;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import java.util.Map;
+import java.io.IOException;
+
+/**
+ * Rabit global class for synchronization.
+ */
+public class Rabit {
+  private static final Log logger = LogFactory.getLog(DMatrix.class);
+  //load native library
+  static {
+    try {
+      NativeLibLoader.initXgBoost();
+    } catch (IOException ex) {
+      logger.error("load native library failed.");
+      logger.error(ex);
+    }
+  }
+
+  private static void checkCall(int ret) throws XGBoostError {
+    if (ret != 0) {
+      throw new XGBoostError(XgboostJNI.XGBGetLastError());
+    }
+  }
+
+  /**
+   * Initialize the rabit library on current working thread.
+   * @param envs The additional environment variables to pass to rabit.
+   * @throws XGBoostError
+   */
+  public static void init(Map<String, String> envs) throws XGBoostError {
+    String[] args = new String[envs.size()];
+    int idx = 0;
+    for (java.util.Map.Entry<String, String> e : envs.entrySet()) {
+      args[idx++] = e.getKey() + '=' + e.getValue();
+    }
+    checkCall(XgboostJNI.RabitInit(args));
+  }
+
+  /**
+   * Shutdown the rabit engine in current working thread, equals to finalize.
+   * @throws XGBoostError
+   */
+  public static void shutdown() throws XGBoostError {
+    checkCall(XgboostJNI.RabitFinalize());
+  }
+
+  /**
+   * Print the message on rabit tracker.
+   * @param msg
+   * @throws XGBoostError
+   */
+  public static void trackerPrint(String msg) throws XGBoostError {
+    checkCall(XgboostJNI.RabitTrackerPrint(msg));
+  }
+
+  /**
+   * Get version number of current stored model in the thread.
+   * which means how many calls to CheckPoint we made so far.
+   * @return version Number.
+   * @throws XGBoostError
+   */
+  public static int versionNumber() throws XGBoostError {
+    int[] out = new int[1];
+    checkCall(XgboostJNI.RabitVersionNumber(out));
+    return out[0];
+  }
+
+  /**
+   * get rank of current thread.
+   * @return the rank.
+   * @throws XGBoostError
+   */
+  public static int getRank() throws XGBoostError {
+    int[] out = new int[1];
+    checkCall(XgboostJNI.RabitGetRank(out));
+    return out[0];
+  }
+
+  /**
+   * get world size of current job.
+   * @return the worldsize
+   * @throws XGBoostError
+   */
+  public static int getWorldSize() throws XGBoostError {
+    int[] out = new int[1];
+    checkCall(XgboostJNI.RabitGetWorldSize(out));
+    return out[0];
+  }
+}

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

@@ -72,15 +72,21 @@ public class XGBoost {
     }
 
     //initialize booster
-    Booster booster = new JavaBoosterImpl(params, allMats);
+    JavaBoosterImpl booster = new JavaBoosterImpl(params, allMats);
+
+    int version = booster.loadRabitCheckpoint();
 
     //begin to train
-    for (int iter = 0; iter < round; iter++) {
+    for (int iter = version / 2; iter < round; iter++) {
+      if (version % 2 == 0) {
         if (obj != null) {
           booster.update(dtrain, obj);
         } else {
           booster.update(dtrain, iter);
         }
+        booster.saveRabitCheckpoint();
+        version += 1;
+      }
 
       //evaluation
       if (evalMats != null && evalMats.length > 0) {
@@ -92,6 +98,8 @@ public class XGBoost {
         }
         logger.info(evalInfo);
       }
+      booster.saveRabitCheckpoint();
+      version += 1;
     }
     return booster;
   }

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

@@ -16,7 +16,7 @@
 package ml.dmlc.xgboost4j;
 
 /**
- * xgboost jni wrapper functions for xgboost_wrapper.h
+ * xgboost JNI functions
  * change 2015-7-6: *use a long[] (length=1) as container of handle to get the output DMatrix or Booster
  *
  * @author hzx
@@ -80,4 +80,17 @@ class XgboostJNI {
 
   public final static native int XGBoosterDumpModel(long handle, String fmap, int with_stats,
                                                     String[][] out_strings);
+
+  public final static native int XGBoosterGetAttr(long handle, String key, String[] out_string);
+  public final static native int XGBoosterSetAttr(long handle, String key, String value);
+  public final static native int XGBoosterLoadRabitCheckpoint(long handle, int[] out_version);
+  public final static native int XGBoosterSaveRabitCheckpoint(long handle);
+
+  // rabit functions
+  public final static native int RabitInit(String[] args);
+  public final static native int RabitFinalize();
+  public final static native int RabitTrackerPrint(String msg);
+  public final static native int RabitGetRank(int[] out);
+  public final static native int RabitGetWorldSize(int[] out);
+  public final static native int RabitVersionNumber(int[] out);
 }                                                                             

jvm-packages/xgboost4j/src/native/xgboost4j.cpp

@@ -12,23 +12,26 @@
   limitations under the License.
 */
 
-#include "xgboost/c_api.h"
+#include <xgboost/c_api.h>
-#include "xgboost4j.h"
+#include "./xgboost4j.h"
 #include <cstring>
+#include <vector>
+#include <string>
 
 //helper functions
 //set handle
 void setHandle(JNIEnv *jenv, jlongArray jhandle, void* handle) {
-    long out[1];
+  long out = (long) handle;
-    out[0] = (long) handle;
+  jenv->SetLongArrayRegion(jhandle, 0, 1, &out);
-    jenv->SetLongArrayRegion(jhandle, 0, 1, (const jlong*) out);
 }
 
 JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBGetLastError
   (JNIEnv *jenv, jclass jcls) {
   jstring jresult = 0;
   const char* result = XGBGetLastError();
-    if (result) jresult = jenv->NewStringUTF(result);
+  if (result != NULL) {
+    jresult = jenv->NewStringUTF(result);
+  }
   return jresult;
 }
 
@@ -37,7 +40,9 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromFile
   DMatrixHandle result;
   const char* fname = jenv->GetStringUTFChars(jfname, 0);
   int ret = XGDMatrixCreateFromFile(fname, jsilent, &result);
-    if (fname) jenv->ReleaseStringUTFChars(jfname, fname);    
+  if (fname) {
+    jenv->ReleaseStringUTFChars(jfname, fname);
+  }
   setHandle(jenv, jout, result);
   return ret;
 }
@@ -271,7 +276,7 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixNumRow
  */
 JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterCreate
   (JNIEnv *jenv, jclass jcls, jlongArray jhandles, jlongArray jout) {
-    DMatrixHandle* handles;
+  DMatrixHandle* handles = NULL;
   bst_ulong len = 0;
   jlong* cjhandles = 0;
   BoosterHandle result;
@@ -293,7 +298,6 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterCreate
     jenv->ReleaseLongArrayElements(jhandles, cjhandles, 0);
   }
   setHandle(jenv, jout, result);
-    
   return ret;
 }
 
@@ -511,3 +515,112 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterDumpModel
   if (fmap) jenv->ReleaseStringUTFChars(jfmap, (const char *)fmap);
   return ret;
 }
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterLoadRabitCheckpoint
+ * Signature: (J[I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadRabitCheckpoint
+  (JNIEnv *jenv , jclass jcls, jlong jhandle, jintArray jout) {
+  BoosterHandle handle = (BoosterHandle) jhandle;
+  int version;
+  int ret = XGBoosterLoadRabitCheckpoint(handle, &version);
+  jenv->SetIntArrayRegion(jout, 0, 1, &version);
+  return ret;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterSaveRabitCheckpoint
+ * Signature: (J)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveRabitCheckpoint
+  (JNIEnv *jenv, jclass jcls, jlong jhandle) {
+  BoosterHandle handle = (BoosterHandle) jhandle;
+  return XGBoosterSaveRabitCheckpoint(handle);
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitInit
+ * Signature: ([Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitInit
+  (JNIEnv *jenv, jclass jcls, jobjectArray jargs) {
+  std::vector<std::string> args;
+  std::vector<char*> argv;
+  bst_ulong len = (bst_ulong)jenv->GetArrayLength(jargs);
+  for (bst_ulong i = 0; i < len; ++i) {
+    jstring arg = (jstring)jenv->GetObjectArrayElement(jargs, i);
+    std::string s(jenv->GetStringUTFChars(arg, 0),
+                  jenv->GetStringLength(arg));
+    if (s.length() != 0) args.push_back(s);
+  }
+
+  for (size_t i = 0; i < args.size(); ++i) {
+    argv.push_back(&args[i][0]);
+  }
+  RabitInit(args.size(), args.size() == 0 ? NULL : &argv[0]);
+  return 0;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitFinalize
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitFinalize
+  (JNIEnv *jenv, jclass jcls) {
+  RabitFinalize();
+  return 0;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitTrackerPrint
+ * Signature: (Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitTrackerPrint
+  (JNIEnv *jenv, jclass jcls, jstring jmsg) {
+  std::string str(jenv->GetStringUTFChars(jmsg, 0),
+                  jenv->GetStringLength(jmsg));
+  RabitTrackerPrint(str.c_str());
+  return 0;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitGetRank
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetRank
+  (JNIEnv *jenv, jclass jcls, jintArray jout) {
+  int rank = RabitGetRank();
+  jenv->SetIntArrayRegion(jout, 0, 1, &rank);
+  return 0;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitGetWorldSize
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetWorldSize
+  (JNIEnv *jenv, jclass jcls, jintArray jout) {
+  int out = RabitGetWorldSize();
+  jenv->SetIntArrayRegion(jout, 0, 1, &out);
+  return 0;
+}
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitVersionNumber
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitVersionNumber
+  (JNIEnv *jenv, jclass jcls, jintArray jout) {
+  int out = RabitVersionNumber();
+  jenv->SetIntArrayRegion(jout, 0, 1, &out);
+  return 0;
+}

jvm-packages/xgboost4j/src/native/xgboost4j.h

@@ -215,6 +215,86 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetModelRaw
 JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterDumpModel
   (JNIEnv *, jclass, jlong, jstring, jint, jobjectArray);
 
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterGetAttr
+ * Signature: (JLjava/lang/String;[Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetAttr
+  (JNIEnv *, jclass, jlong, jstring, jobjectArray);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterSetAttr
+ * Signature: (JLjava/lang/String;Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSetAttr
+  (JNIEnv *, jclass, jlong, jstring, jstring);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterLoadRabitCheckpoint
+ * Signature: (J[I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadRabitCheckpoint
+  (JNIEnv *, jclass, jlong, jintArray);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    XGBoosterSaveRabitCheckpoint
+ * Signature: (J)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveRabitCheckpoint
+  (JNIEnv *, jclass, jlong);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitInit
+ * Signature: ([Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitInit
+  (JNIEnv *, jclass, jobjectArray);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitFinalize
+ * Signature: ()I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitFinalize
+  (JNIEnv *, jclass);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitTrackerPrint
+ * Signature: (Ljava/lang/String;)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitTrackerPrint
+  (JNIEnv *, jclass, jstring);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitGetRank
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetRank
+  (JNIEnv *, jclass, jintArray);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitGetWorldSize
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetWorldSize
+  (JNIEnv *, jclass, jintArray);
+
+/*
+ * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Method:    RabitVersionNumber
+ * Signature: ([I)I
+ */
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitVersionNumber
+  (JNIEnv *, jclass, jintArray);
+
 #ifdef __cplusplus
 }
 #endif