8dd96013f1
* Split up column matrix initialization. This PR splits the column matrix initialization into 2 steps, the first one initializes the storage while the second one does the transpose. By doing so, we can reuse the code for Quantile DMatrix.
66 lines
1.9 KiB
C++
66 lines
1.9 KiB
C++
/*!
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* Copyright 2017-2022 by XGBoost Contributors
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* \brief Utility for fast column-wise access
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*/
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#include "column_matrix.h"
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namespace xgboost {
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namespace common {
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void ColumnMatrix::InitStorage(GHistIndexMatrix const& gmat, double sparse_threshold) {
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auto const nfeature = gmat.Features();
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const size_t nrow = gmat.Size();
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// identify type of each column
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type_.resize(nfeature);
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uint32_t max_val = std::numeric_limits<uint32_t>::max();
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for (bst_feature_t fid = 0; fid < nfeature; ++fid) {
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CHECK_LE(gmat.cut.Ptrs()[fid + 1] - gmat.cut.Ptrs()[fid], max_val);
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}
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bool all_dense_column = true;
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std::vector<size_t> feature_counts(nfeature, 0);
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gmat.GetFeatureCounts(feature_counts.data());
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// classify features
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for (bst_feature_t fid = 0; fid < nfeature; ++fid) {
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if (static_cast<double>(feature_counts[fid]) < sparse_threshold * nrow) {
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type_[fid] = kSparseColumn;
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all_dense_column = false;
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} else {
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type_[fid] = kDenseColumn;
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}
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}
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// want to compute storage boundary for each feature
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// using variants of prefix sum scan
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feature_offsets_.resize(nfeature + 1);
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size_t accum_index = 0;
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feature_offsets_[0] = accum_index;
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for (bst_feature_t fid = 1; fid < nfeature + 1; ++fid) {
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if (type_[fid - 1] == kDenseColumn) {
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accum_index += static_cast<size_t>(nrow);
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} else {
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accum_index += feature_counts[fid - 1];
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}
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feature_offsets_[fid] = accum_index;
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}
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SetTypeSize(gmat.max_num_bins);
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auto storage_size =
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feature_offsets_.back() * static_cast<std::underlying_type_t<BinTypeSize>>(bins_type_size_);
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index_.resize(storage_size, 0);
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if (!all_dense_column) {
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row_ind_.resize(feature_offsets_[nfeature]);
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}
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// store least bin id for each feature
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index_base_ = const_cast<uint32_t*>(gmat.cut.Ptrs().data());
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any_missing_ = !gmat.IsDense();
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missing_flags_.clear();
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}
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} // namespace common
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} // namespace xgboost
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