Feature weights (dmlc#5962) (#3)

* Update BoosterParams.scala

* fix scala checkstyle error

* fix whitespace checkstyle error

* fix type cast error

* fix conversion issue

* update version for 1.2.5-al

* Feature weights (dmlc#5962)

* update version

* version update 2

Co-authored-by: Oscar Pan <oscar.pan@applovin.com>
Co-authored-by: Jiaming Yuan <jm.yuan@outlook.com>

amalgamation/xgboost-all0.cc

@@ -69,6 +69,7 @@
 #include "../src/learner.cc"
 #include "../src/logging.cc"
 #include "../src/common/common.cc"
+#include "../src/common/random.cc"
 #include "../src/common/charconv.cc"
 #include "../src/common/timer.cc"
 #include "../src/common/host_device_vector.cc"

demo/guide-python/feature_weights.py

@@ -0,0 +1,49 @@
+'''Using feature weight to change column sampling.
+
+    .. versionadded:: 1.3.0
+'''
+
+import numpy as np
+import xgboost
+from matplotlib import pyplot as plt
+import argparse
+
+
+def main(args):
+    rng = np.random.RandomState(1994)
+
+    kRows = 1000
+    kCols = 10
+
+    X = rng.randn(kRows, kCols)
+    y = rng.randn(kRows)
+    fw = np.ones(shape=(kCols,))
+    for i in range(kCols):
+        fw[i] *= float(i)
+
+    dtrain = xgboost.DMatrix(X, y)
+    dtrain.set_info(feature_weights=fw)
+
+    bst = xgboost.train({'tree_method': 'hist',
+                         'colsample_bynode': 0.5},
+                        dtrain, num_boost_round=10,
+                        evals=[(dtrain, 'd')])
+    featue_map = bst.get_fscore()
+    # feature zero has 0 weight
+    assert featue_map.get('f0', None) is None
+    assert max(featue_map.values()) == featue_map.get('f9')
+
+    if args.plot:
+        xgboost.plot_importance(bst)
+        plt.show()
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--plot',
+        type=int,
+        default=1,
+        help='Set to 0 to disable plotting the evaluation history.')
+    args = parser.parse_args()
+    main(args)

demo/json-model/json_parser.py

@@ -94,7 +94,7 @@ def __str__(self):
 
 class Model:
     '''Gradient boosted tree model.'''
-    def __init__(self, m: dict):
+    def __init__(self, model: dict):
         '''Construct the Model from JSON object.
 
          parameters

doc/parameter.rst

@@ -107,6 +107,10 @@ Parameters for Tree Booster
     'colsample_bynode':0.5}`` with 64 features will leave 8 features to choose from at
     each split.
 
+    On Python interface, one can set the ``feature_weights`` for DMatrix to define the
+    probability of each feature being selected when using column sampling.  There's a
+    similar parameter for ``fit`` method in sklearn interface.
+
 * ``lambda`` [default=1, alias: ``reg_lambda``]
 
   - L2 regularization term on weights. Increasing this value will make model more conservative.
@@ -225,9 +229,8 @@ Parameters for Tree Booster
     list is a group of indices of features that are allowed to interact with each other.
     See tutorial for more information
 
-Additional parameters for `hist` and 'gpu_hist' tree method
-================================================
-
+Additional parameters for ``hist`` and ``gpu_hist`` tree method
+================================================================
 * ``single_precision_histogram``, [default=``false``]
 
   - Use single precision to build histograms instead of double precision.

include/xgboost/c_api.h

@@ -483,6 +483,34 @@ XGB_DLL int XGDMatrixGetStrFeatureInfo(DMatrixHandle handle, const char *field,
                                        bst_ulong *size,
                                        const char ***out_features);
 
+/*!
+ * \brief Set meta info from dense matrix.  Valid field names are:
+ *
+ *  - label
+ *  - weight
+ *  - base_margin
+ *  - group
+ *  - label_lower_bound
+ *  - label_upper_bound
+ *  - feature_weights
+ *
+ * \param handle An instance of data matrix
+ * \param field  Feild name
+ * \param data   Pointer to consecutive memory storing data.
+ * \param size   Size of the data, this is relative to size of type.  (Meaning NOT number
+ *               of bytes.)
+ * \param type   Indicator of data type.  This is defined in xgboost::DataType enum class.
+ *
+ *    float    = 1
+ *    double   = 2
+ *    uint32_t = 3
+ *    uint64_t = 4
+ *
+ * \return 0 when success, -1 when failure happens
+ */
+XGB_DLL int XGDMatrixSetDenseInfo(DMatrixHandle handle, const char *field,
+                                  void *data, bst_ulong size, int type);
+
 /*!
  * \brief (deprecated) Use XGDMatrixSetUIntInfo instead. Set group of the training matrix
  * \param handle a instance of data matrix

include/xgboost/data.h

@@ -89,34 +89,17 @@ class MetaInfo {
    * \brief Type of each feature.  Automatically set when feature_type_names is specifed.
    */
   HostDeviceVector<FeatureType> feature_types;
+  /*
+   * \brief Weight of each feature, used to define the probability of each feature being
+   *        selected when using column sampling.
+   */
+  HostDeviceVector<float> feature_weigths;
 
   /*! \brief default constructor */
   MetaInfo()  = default;
   MetaInfo(MetaInfo&& that) = default;
   MetaInfo& operator=(MetaInfo&& that) = default;
-  MetaInfo& operator=(MetaInfo const& that) {
-    this->num_row_ = that.num_row_;
-    this->num_col_ = that.num_col_;
-    this->num_nonzero_ = that.num_nonzero_;
-
-    this->labels_.Resize(that.labels_.Size());
-    this->labels_.Copy(that.labels_);
-
-    this->group_ptr_ = that.group_ptr_;
-
-    this->weights_.Resize(that.weights_.Size());
-    this->weights_.Copy(that.weights_);
-
-    this->base_margin_.Resize(that.base_margin_.Size());
-    this->base_margin_.Copy(that.base_margin_);
-
-    this->labels_lower_bound_.Resize(that.labels_lower_bound_.Size());
-    this->labels_lower_bound_.Copy(that.labels_lower_bound_);
-
-    this->labels_upper_bound_.Resize(that.labels_upper_bound_.Size());
-    this->labels_upper_bound_.Copy(that.labels_upper_bound_);
-    return *this;
-  }
+  MetaInfo& operator=(MetaInfo const& that) = delete;
 
   /*!
    * \brief Validate all metainfo.

jvm-packages/pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>ml.dmlc</groupId>
     <artifactId>xgboost-jvm_2.12</artifactId>
-    <version>1.2.4-al</version>
+    <version>1.2.6-al</version>
     <packaging>pom</packaging>
     <name>XGBoost JVM Package</name>
     <description>JVM Package for XGBoost</description>

jvm-packages/xgboost4j-example/pom.xml

@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.2.4-al</version>
+        <version>1.2.6-al</version>
     </parent>
     <artifactId>xgboost4j-example_2.12</artifactId>
-    <version>1.2.4-al</version>
+    <version>1.2.6-al</version>
     <packaging>jar</packaging>
     <build>
         <plugins>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-spark_${scala.binary.version}</artifactId>
-            <version>1.2.4-al</version>
+            <version>1.2.6-al</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>
@@ -37,7 +37,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j-flink_${scala.binary.version}</artifactId>
-            <version>1.2.4-al</version>
+            <version>1.2.6-al</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

jvm-packages/xgboost4j-flink/pom.xml

@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.2.4-al</version>
+        <version>1.2.6-al</version>
     </parent>
     <artifactId>xgboost4j-flink_2.12</artifactId>
-    <version>1.2.4-al</version>
+    <version>1.2.6-al</version>
     <build>
         <plugins>
             <plugin>
@@ -26,7 +26,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.2.4-al</version>
+            <version>1.2.6-al</version>
         </dependency>
         <dependency>
             <groupId>org.apache.commons</groupId>

jvm-packages/xgboost4j-spark/pom.xml

@@ -6,7 +6,7 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.2.4-al</version>
+        <version>1.2.6-al</version>
     </parent>
     <artifactId>xgboost4j-spark_2.12</artifactId>
     <build>
@@ -24,7 +24,7 @@
         <dependency>
             <groupId>ml.dmlc</groupId>
             <artifactId>xgboost4j_${scala.binary.version}</artifactId>
-            <version>1.2.4-al</version>
+            <version>1.2.6-al</version>
         </dependency>
         <dependency>
             <groupId>org.apache.spark</groupId>

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

@@ -99,7 +99,7 @@ private[this] class XGBoostExecutionParamsFactory(rawParams: Map[String, Any], s
 
   private val isLocal = sc.isLocal
 
-  private val overridedParams = overrideParams(rawParams, sc)
+  private val overridedParams: Map[String, Any] = overrideParams(rawParams, sc)
 
   /**
    * Check to see if Spark expects SSL encryption (`spark.ssl.enabled` set to true).
@@ -213,7 +213,8 @@ private[this] class XGBoostExecutionParamsFactory(rawParams: Map[String, Any], s
       .asInstanceOf[Double]
     val seed = overridedParams.getOrElse("seed", System.nanoTime()).asInstanceOf[Long]
     val featureWeights = overridedParams.getOrElse(
-      "feature_weights", new Array[Float](0)).asInstanceOf[Array[Float]]
+      "feature_weights", new Array[Double](0)).asInstanceOf[Array[Double]]
+      .map(_.toFloat)
     val inputParams = XGBoostExecutionInputParams(trainTestRatio, seed, featureWeights)
 
     val earlyStoppingRounds = overridedParams.getOrElse(

jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/params/BoosterParams.scala

@@ -17,8 +17,7 @@
 package ml.dmlc.xgboost4j.scala.spark.params
 
 import scala.collection.immutable.HashSet
-
-import org.apache.spark.ml.param.{DoubleParam, IntParam, BooleanParam, Param, Params}
+import org.apache.spark.ml.param.{BooleanParam, DoubleArrayParam, DoubleParam, IntParam, Param, Params}
 
 private[spark] trait BoosterParams extends Params {
 
@@ -110,6 +109,15 @@ private[spark] trait BoosterParams extends Params {
 
   final def getSubsample: Double = $(subsample)
 
+  /**
+   * Probability distribution for column sampling. Doesn't have to be normalized
+   */
+  final val featureWeights = new DoubleArrayParam(this, "featureWeights",
+    "probability distribution " +
+    "for feature sampling.", (value: Array[Double]) => true)
+
+  final def getFeatureWeights: Array[Double] = $(featureWeights)
+
   /**
    * subsample ratio of columns when constructing each tree. [default=1] range: (0,1]
    */
@@ -286,7 +294,8 @@ private[spark] trait BoosterParams extends Params {
     subsample -> 1, colsampleBytree -> 1, colsampleBylevel -> 1,
     lambda -> 1, alpha -> 0, treeMethod -> "auto", sketchEps -> 0.03,
     scalePosWeight -> 1.0, sampleType -> "uniform", normalizeType -> "tree",
-    rateDrop -> 0.0, skipDrop -> 0.0, lambdaBias -> 0, treeLimit -> 0)
+    rateDrop -> 0.0, skipDrop -> 0.0, lambdaBias -> 0, treeLimit -> 0,
+    featureWeights -> new Array[Double](0))
 }
 
 private[spark] object BoosterParams {

jvm-packages/xgboost4j/pom.xml

@@ -6,10 +6,10 @@
     <parent>
         <groupId>ml.dmlc</groupId>
         <artifactId>xgboost-jvm_2.12</artifactId>
-        <version>1.2.4-al</version>
+        <version>1.2.6-al</version>
     </parent>
     <artifactId>xgboost4j_2.12</artifactId>
-    <version>1.2.4-al</version>
+    <version>1.2.6-al</version>
     <packaging>jar</packaging>
 
     <dependencies>

python-package/xgboost/core.py

@@ -455,7 +455,8 @@ def set_info(self,
                  label_lower_bound=None,
                  label_upper_bound=None,
                  feature_names=None,
-                 feature_types=None):
+                 feature_types=None,
+                 feature_weights=None):
         '''Set meta info for DMatrix.'''
         if label is not None:
             self.set_label(label)
@@ -473,6 +474,10 @@ def set_info(self,
             self.feature_names = feature_names
         if feature_types is not None:
             self.feature_types = feature_types
+        if feature_weights is not None:
+            from .data import dispatch_meta_backend
+            dispatch_meta_backend(matrix=self, data=feature_weights,
+                                  name='feature_weights')
 
     def get_float_info(self, field):
         """Get float property from the DMatrix.

python-package/xgboost/data.py

@@ -530,22 +530,38 @@ def dispatch_data_backend(data, missing, threads,
     raise TypeError('Not supported type for data.' + str(type(data)))
 
 
+def _to_data_type(dtype: str, name: str):
+    dtype_map = {'float32': 1, 'float64': 2, 'uint32': 3, 'uint64': 4}
+    if dtype not in dtype_map.keys():
+        raise TypeError(
+            f'Expecting float32, float64, uint32, uint64, got {dtype} ' +
+            f'for {name}.')
+    return dtype_map[dtype]
+
+
+def _validate_meta_shape(data):
+    if hasattr(data, 'shape'):
+        assert len(data.shape) == 1 or (
+            len(data.shape) == 2 and
+            (data.shape[1] == 0 or data.shape[1] == 1))
+
+
 def _meta_from_numpy(data, field, dtype, handle):
     data = _maybe_np_slice(data, dtype)
-    if dtype == 'uint32':
-        c_data = c_array(ctypes.c_uint32, data)
-        _check_call(_LIB.XGDMatrixSetUIntInfo(handle,
-                                              c_str(field),
-                                              c_array(ctypes.c_uint, data),
-                                              c_bst_ulong(len(data))))
-    elif dtype == 'float':
-        c_data = c_array(ctypes.c_float, data)
-        _check_call(_LIB.XGDMatrixSetFloatInfo(handle,
-                                               c_str(field),
-                                               c_data,
-                                               c_bst_ulong(len(data))))
-    else:
-        raise TypeError('Unsupported type ' + str(dtype) + ' for:' + field)
+    interface = data.__array_interface__
+    assert interface.get('mask', None) is None, 'Masked array is not supported'
+    size = data.shape[0]
+
+    c_type = _to_data_type(str(data.dtype), field)
+    ptr = interface['data'][0]
+    ptr = ctypes.c_void_p(ptr)
+    _check_call(_LIB.XGDMatrixSetDenseInfo(
+        handle,
+        c_str(field),
+        ptr,
+        c_bst_ulong(size),
+        c_type
+    ))
 
 
 def _meta_from_list(data, field, dtype, handle):
@@ -595,6 +611,7 @@ def _meta_from_dt(data, field, dtype, handle):
 def dispatch_meta_backend(matrix: DMatrix, data, name: str, dtype: str = None):
     '''Dispatch for meta info.'''
     handle = matrix.handle
+    _validate_meta_shape(data)
     if data is None:
         return
     if _is_list(data):