From 4b892c2b30cf1a65f6bd4ce33d5c7cd18b8fa43b Mon Sep 17 00:00:00 2001
From: trivialfis <ybbs.daans@hotmail.com>
Date: Sun, 7 Oct 2018 07:22:15 +1300
Subject: [PATCH] Remove obsoleted QuantileHistMaker. (#3761)

Fix #3755.
---
 src/tree/updater_histmaker.cc | 124 ----------------------------------
 1 file changed, 124 deletions(-)

diff --git a/src/tree/updater_histmaker.cc b/src/tree/updater_histmaker.cc
index e0167afa4..0beb623e2 100644
--- a/src/tree/updater_histmaker.cc
+++ b/src/tree/updater_histmaker.cc
@@ -746,130 +746,6 @@ class GlobalProposalHistMaker: public CQHistMaker<TStats> {
   std::vector<bst_float> cached_cut_;
 };
 
-
-template<typename TStats>
-class QuantileHistMaker: public HistMaker<TStats> {
- protected:
-  using WXQSketch = common::WXQuantileSketch<bst_float, bst_float>;
-  void ResetPosAndPropose(const std::vector<GradientPair> &gpair,
-                          DMatrix *p_fmat,
-                          const std::vector <bst_uint> &fset,
-                          const RegTree &tree) override {
-    const MetaInfo &info = p_fmat->Info();
-    // initialize the data structure
-    const int nthread = omp_get_max_threads();
-    sketchs_.resize(this->qexpand_.size() * tree.param.num_feature);
-    for (size_t i = 0; i < sketchs_.size(); ++i) {
-      sketchs_[i].Init(info.num_row_, this->param_.sketch_eps);
-    }
-    // start accumulating statistics
-    for (const auto &batch : p_fmat->GetRowBatches()) {
-      // parallel convert to column major format
-      common::ParallelGroupBuilder<Entry>
-          builder(&col_ptr_, &col_data_, &thread_col_ptr_);
-      builder.InitBudget(tree.param.num_feature, nthread);
-
-      const bst_omp_uint nbatch = static_cast<bst_omp_uint>(batch.Size());
-      #pragma omp parallel for schedule(static)
-      for (bst_omp_uint i = 0; i < nbatch; ++i) {
-        SparsePage::Inst inst = batch[i];
-        const bst_uint ridx = static_cast<bst_uint>(batch.base_rowid + i);
-        int nid = this->position_[ridx];
-        if (nid >= 0) {
-          if (!tree[nid].IsLeaf()) {
-            this->position_[ridx] = nid = HistMaker<TStats>::NextLevel(inst, tree, nid);
-          }
-          if (this->node2workindex_[nid] < 0) {
-            this->position_[ridx] = ~nid;
-          } else {
-            for (auto& ins : inst) {
-              builder.AddBudget(ins.index, omp_get_thread_num());
-            }
-          }
-        }
-      }
-      builder.InitStorage();
-      #pragma omp parallel for schedule(static)
-      for (bst_omp_uint i = 0; i < nbatch; ++i) {
-        SparsePage::Inst inst = batch[i];
-        const bst_uint ridx = static_cast<bst_uint>(batch.base_rowid + i);
-        const int nid = this->position_[ridx];
-        if (nid >= 0) {
-          for (auto& ins : inst) {
-            builder.Push(ins.index,
-                         Entry(nid, ins.fvalue),
-                         omp_get_thread_num());
-          }
-        }
-      }
-      // start putting things into sketch
-      const bst_omp_uint nfeat = col_ptr_.size() - 1;
-      #pragma omp parallel for schedule(dynamic, 1)
-      for (bst_omp_uint k = 0; k < nfeat; ++k) {
-        for (size_t i = col_ptr_[k]; i < col_ptr_[k+1]; ++i) {
-          const Entry &e = col_data_[i];
-          const int wid = this->node2workindex_[e.index];
-          sketchs_[wid * tree.param.num_feature + k].Push(e.fvalue, gpair[e.index].GetHess());
-        }
-      }
-    }
-    // setup maximum size
-    unsigned max_size = this->param_.MaxSketchSize();
-    // synchronize sketch
-    summary_array_.resize(sketchs_.size());
-    for (size_t i = 0; i < sketchs_.size(); ++i) {
-      common::WQuantileSketch<bst_float, bst_float>::SummaryContainer out;
-      sketchs_[i].GetSummary(&out);
-      summary_array_[i].Reserve(max_size);
-      summary_array_[i].SetPrune(out, max_size);
-    }
-
-    size_t nbytes = WXQSketch::SummaryContainer::CalcMemCost(max_size);
-    sreducer_.Allreduce(dmlc::BeginPtr(summary_array_), nbytes, summary_array_.size());
-    // now we get the final result of sketch, setup the cut
-    this->wspace_.cut.clear();
-    this->wspace_.rptr.clear();
-    this->wspace_.rptr.push_back(0);
-    for (size_t wid = 0; wid < this->qexpand_.size(); ++wid) {
-      for (int fid = 0; fid < tree.param.num_feature; ++fid) {
-        const WXQSketch::Summary &a = summary_array_[wid * tree.param.num_feature + fid];
-        for (size_t i = 1; i < a.size; ++i) {
-          bst_float cpt = a.data[i].value - kRtEps;
-          if (i == 1 || cpt > this->wspace_.cut.back()) {
-            this->wspace_.cut.push_back(cpt);
-          }
-        }
-        // push a value that is greater than anything
-        if (a.size != 0) {
-          bst_float cpt = a.data[a.size - 1].value;
-          // this must be bigger than last value in a scale
-          bst_float last = cpt + fabs(cpt) + kRtEps;
-          this->wspace_.cut.push_back(last);
-        }
-        this->wspace_.rptr.push_back(this->wspace_.cut.size());
-      }
-      // reserve last value for global statistics
-      this->wspace_.cut.push_back(0.0f);
-      this->wspace_.rptr.push_back(this->wspace_.cut.size());
-    }
-    CHECK_EQ(this->wspace_.rptr.size(),
-             (tree.param.num_feature + 1) * this->qexpand_.size() + 1);
-  }
-
- private:
-  // summary array
-  std::vector<WXQSketch::SummaryContainer> summary_array_;
-  // reducer for summary
-  rabit::SerializeReducer<WXQSketch::SummaryContainer> sreducer_;
-  // local temp column data structure
-  std::vector<size_t> col_ptr_;
-  // local storage of column data
-  std::vector<Entry> col_data_;
-  std::vector<std::vector<size_t> > thread_col_ptr_;
-  // per node, per feature sketch
-  std::vector<common::WQuantileSketch<bst_float, bst_float> > sketchs_;
-};
-
 XGBOOST_REGISTER_TREE_UPDATER(LocalHistMaker, "grow_local_histmaker")
 .describe("Tree constructor that uses approximate histogram construction.")
 .set_body([]() {