Rename and extract Context.

R-package/src/Makevars.in

@@ -68,6 +68,7 @@ OBJECTS= \
     $(PKGROOT)/src/linear/updater_coordinate.o \
     $(PKGROOT)/src/linear/updater_shotgun.o \
     $(PKGROOT)/src/learner.o \
+    $(PKGROOT)/src/context.o \
     $(PKGROOT)/src/logging.o \
     $(PKGROOT)/src/global_config.o \
     $(PKGROOT)/src/collective/communicator.o \

R-package/src/Makevars.win

@@ -68,6 +68,7 @@ OBJECTS= \
     $(PKGROOT)/src/linear/updater_coordinate.o \
     $(PKGROOT)/src/linear/updater_shotgun.o \
     $(PKGROOT)/src/learner.o \
+    $(PKGROOT)/src/context.o \
     $(PKGROOT)/src/logging.o \
     $(PKGROOT)/src/global_config.o \
     $(PKGROOT)/src/collective/communicator.o \

R-package/src/xgboost_R.cc

@@ -4,8 +4,8 @@
 #include <dmlc/common.h>
 #include <dmlc/omp.h>
 #include <xgboost/c_api.h>
+#include <xgboost/context.h>
 #include <xgboost/data.h>
-#include <xgboost/generic_parameters.h>
 #include <xgboost/logging.h>
 
 #include <cstdio>
@@ -18,7 +18,8 @@
 #include "../../src/c_api/c_api_error.h"
 #include "../../src/common/threading_utils.h"
 
-#include "./xgboost_R.h"
+
+#include "./xgboost_R.h"  // Must follow other include.
 
 /*!
  * \brief macro to annotate begin of api
@@ -46,14 +47,14 @@
 
 using dmlc::BeginPtr;
 
-xgboost::GenericParameter const *BoosterCtx(BoosterHandle handle) {
+xgboost::Context const *BoosterCtx(BoosterHandle handle) {
   CHECK_HANDLE();
   auto *learner = static_cast<xgboost::Learner *>(handle);
   CHECK(learner);
   return learner->Ctx();
 }
 
-xgboost::GenericParameter const *DMatrixCtx(DMatrixHandle handle) {
+xgboost::Context const *DMatrixCtx(DMatrixHandle handle) {
   CHECK_HANDLE();
   auto p_m = static_cast<std::shared_ptr<xgboost::DMatrix> *>(handle);
   CHECK(p_m);

include/xgboost/generic_parameters.h → include/xgboost/context.h

@@ -1,9 +1,9 @@
 /*!
- * Copyright 2014-2019 by Contributors
- * \file generic_parameters.h
+ * Copyright 2014-2022 by Contributors
+ * \file context.h
  */
-#ifndef XGBOOST_GENERIC_PARAMETERS_H_
-#define XGBOOST_GENERIC_PARAMETERS_H_
+#ifndef XGBOOST_CONTEXT_H_
+#define XGBOOST_CONTEXT_H_
 
 #include <xgboost/logging.h>
 #include <xgboost/parameter.h>
@@ -12,31 +12,31 @@
 
 namespace xgboost {
 
-struct GenericParameter : public XGBoostParameter<GenericParameter> {
+struct Context : public XGBoostParameter<Context> {
  private:
   // cached value for CFS CPU limit. (used in containerized env)
-  int32_t cfs_cpu_count_;  // NOLINT
+  std::int32_t cfs_cpu_count_;  // NOLINT
 
  public:
   // Constant representing the device ID of CPU.
-  static int32_t constexpr kCpuId = -1;
-  static int64_t constexpr kDefaultSeed = 0;
+  static std::int32_t constexpr kCpuId = -1;
+  static std::int64_t constexpr kDefaultSeed = 0;
 
  public:
-  GenericParameter();
+  Context();
 
   // stored random seed
-  int64_t seed { kDefaultSeed };
+  std::int64_t seed{kDefaultSeed};
   // whether seed the PRNG each iteration
   bool seed_per_iteration{false};
   // number of threads to use if OpenMP is enabled
   // if equals 0, use system default
-  int nthread{0};
+  std::int32_t nthread{0};
   // primary device, -1 means no gpu.
-  int gpu_id{kCpuId};
+  std::int32_t gpu_id{kCpuId};
   // fail when gpu_id is invalid
-  bool fail_on_invalid_gpu_id {false};
-  bool validate_parameters {false};
+  bool fail_on_invalid_gpu_id{false};
+  bool validate_parameters{false};
 
   /*!
    * \brief Configure the parameter `gpu_id'.
@@ -47,26 +47,25 @@ struct GenericParameter : public XGBoostParameter<GenericParameter> {
   /*!
    * Return automatically chosen threads.
    */
-  int32_t Threads() const;
+  std::int32_t Threads() const;
 
   bool IsCPU() const { return gpu_id == kCpuId; }
+  bool IsCUDA() const { return !IsCPU(); }
 
   // declare parameters
-  DMLC_DECLARE_PARAMETER(GenericParameter) {
-    DMLC_DECLARE_FIELD(seed).set_default(kDefaultSeed).describe(
-        "Random number seed during training.");
+  DMLC_DECLARE_PARAMETER(Context) {
+    DMLC_DECLARE_FIELD(seed)
+        .set_default(kDefaultSeed)
+        .describe("Random number seed during training.");
     DMLC_DECLARE_ALIAS(seed, random_state);
     DMLC_DECLARE_FIELD(seed_per_iteration)
         .set_default(false)
         .describe("Seed PRNG determnisticly via iterator number.");
-    DMLC_DECLARE_FIELD(nthread).set_default(0).describe(
-        "Number of threads to use.");
+    DMLC_DECLARE_FIELD(nthread).set_default(0).describe("Number of threads to use.");
     DMLC_DECLARE_ALIAS(nthread, n_jobs);
 
-    DMLC_DECLARE_FIELD(gpu_id)
-        .set_default(-1)
-        .set_lower_bound(-1)
-        .describe("The primary GPU device ordinal.");
+    DMLC_DECLARE_FIELD(gpu_id).set_default(-1).set_lower_bound(-1).describe(
+        "The primary GPU device ordinal.");
     DMLC_DECLARE_FIELD(fail_on_invalid_gpu_id)
         .set_default(false)
         .describe("Fail with error when gpu_id is invalid.");
@@ -75,8 +74,6 @@ struct GenericParameter : public XGBoostParameter<GenericParameter> {
         .describe("Enable checking whether parameters are used or not.");
   }
 };
-
-using Context = GenericParameter;
 }  // namespace xgboost
 
-#endif  // XGBOOST_GENERIC_PARAMETERS_H_
+#endif  // XGBOOST_CONTEXT_H_

include/xgboost/data.h

@@ -11,7 +11,6 @@
 #include <dmlc/data.h>
 #include <dmlc/serializer.h>
 #include <xgboost/base.h>
-#include <xgboost/generic_parameters.h>
 #include <xgboost/host_device_vector.h>
 #include <xgboost/linalg.h>
 #include <xgboost/span.h>
@@ -28,6 +27,7 @@
 namespace xgboost {
 // forward declare dmatrix.
 class DMatrix;
+struct Context;
 
 /*! \brief data type accepted by xgboost interface */
 enum class DataType : uint8_t {

include/xgboost/gbm.h

@@ -28,7 +28,7 @@ class Json;
 class FeatureMap;
 class ObjFunction;
 
-struct GenericParameter;
+struct Context;
 struct LearnerModelParam;
 struct PredictionCacheEntry;
 class PredictionContainer;
@@ -38,8 +38,8 @@ class PredictionContainer;
  */
 class GradientBooster : public Model, public Configurable {
  protected:
-  GenericParameter const* ctx_;
-  explicit GradientBooster(GenericParameter const* ctx) : ctx_{ctx} {}
+  Context const* ctx_;
+  explicit GradientBooster(Context const* ctx) : ctx_{ctx} {}
 
  public:
   /*! \brief virtual destructor */
@@ -193,10 +193,8 @@ class GradientBooster : public Model, public Configurable {
    * \param learner_model_param pointer to global model parameters
    * \return The created booster.
    */
-  static GradientBooster* Create(
-      const std::string& name,
-      GenericParameter const* generic_param,
-      LearnerModelParam const* learner_model_param);
+  static GradientBooster* Create(const std::string& name, Context const* ctx,
+                                 LearnerModelParam const* learner_model_param);
 };
 
 /*!
@@ -206,7 +204,7 @@ struct GradientBoosterReg
     : public dmlc::FunctionRegEntryBase<
           GradientBoosterReg,
           std::function<GradientBooster*(LearnerModelParam const* learner_model_param,
-                                         GenericParameter const* ctx)> > {};
+                                         Context const* ctx)> > {};
 
 /*!
  * \brief Macro to register gradient booster.

include/xgboost/learner.h

@@ -9,8 +9,8 @@
 #define XGBOOST_LEARNER_H_
 
 #include <xgboost/base.h>
+#include <xgboost/context.h>  // Context
 #include <xgboost/feature_map.h>
-#include <xgboost/generic_parameters.h>  // Context
 #include <xgboost/host_device_vector.h>
 #include <xgboost/model.h>
 #include <xgboost/predictor.h>

include/xgboost/linalg.h

@@ -8,7 +8,7 @@
 
 #include <dmlc/endian.h>
 #include <xgboost/base.h>
-#include <xgboost/generic_parameters.h>
+#include <xgboost/context.h>  // fixme(jiamingy): Remove the dependency on this header.
 #include <xgboost/host_device_vector.h>
 #include <xgboost/json.h>
 #include <xgboost/span.h>

include/xgboost/linear_updater.h

@@ -6,7 +6,6 @@
 #include <dmlc/registry.h>
 #include <xgboost/base.h>
 #include <xgboost/data.h>
-#include <xgboost/generic_parameters.h>
 #include <xgboost/host_device_vector.h>
 #include <xgboost/model.h>
 
@@ -19,6 +18,7 @@
 namespace xgboost {
 
 class Json;
+struct Context;
 
 namespace gbm {
 class GBLinearModel;
@@ -29,7 +29,7 @@ class GBLinearModel;
  */
 class LinearUpdater : public Configurable {
  protected:
-  GenericParameter const* ctx_;
+  Context const* ctx_;
 
  public:
   /*! \brief virtual destructor */
@@ -57,7 +57,7 @@ class LinearUpdater : public Configurable {
    * \brief Create a linear updater given name
    * \param name Name of the linear updater.
    */
-  static LinearUpdater* Create(const std::string& name, GenericParameter const*);
+  static LinearUpdater* Create(const std::string& name, Context const*);
 };
 
 /*!

include/xgboost/metric.h

@@ -9,7 +9,6 @@
 
 #include <dmlc/registry.h>
 #include <xgboost/model.h>
-#include <xgboost/generic_parameters.h>
 #include <xgboost/data.h>
 #include <xgboost/base.h>
 #include <xgboost/host_device_vector.h>
@@ -20,13 +19,15 @@
 #include <utility>
 
 namespace xgboost {
+struct Context;
+
 /*!
  * \brief interface of evaluation metric used to evaluate model performance.
  *  This has nothing to do with training, but merely act as evaluation purpose.
  */
 class Metric : public Configurable {
  protected:
-  GenericParameter const* tparam_;
+  Context const* tparam_;
 
  public:
   /*!
@@ -68,10 +69,10 @@ class Metric : public Configurable {
    * \param name name of the metric.
    *        name can be in form metric[@]param and the name will be matched in the
    *        registry.
-   * \param tparam A global generic parameter
+   * \param ctx A global context
    * \return the created metric.
    */
-  static Metric* Create(const std::string& name, GenericParameter const* tparam);
+  static Metric* Create(const std::string& name, Context const* ctx);
 };
 
 /*!

include/xgboost/objective.h

@@ -10,19 +10,19 @@
 #include <dmlc/registry.h>
 #include <xgboost/base.h>
 #include <xgboost/data.h>
-#include <xgboost/model.h>
-#include <xgboost/generic_parameters.h>
 #include <xgboost/host_device_vector.h>
+#include <xgboost/model.h>
 #include <xgboost/task.h>
 
-#include <vector>
-#include <utility>
-#include <string>
 #include <functional>
+#include <string>
+#include <utility>
+#include <vector>
 
 namespace xgboost {
 
 class RegTree;
+struct Context;
 
 /*! \brief interface of objective function */
 class ObjFunction : public Configurable {
@@ -120,10 +120,10 @@ class ObjFunction : public Configurable {
 
   /*!
    * \brief Create an objective function according to name.
-   * \param tparam Generic parameters.
+   * \param ctx  Pointer to runtime parameters.
    * \param name Name of the objective.
    */
-  static ObjFunction* Create(const std::string& name, GenericParameter const* tparam);
+  static ObjFunction* Create(const std::string& name, Context const* ctx);
 };
 
 /*!