55 lines
2.5 KiB
C++
55 lines
2.5 KiB
C++
/*!
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* Copyright 2017 by Contributors
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* \file updater_fast_hist.h
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* \brief parameters for histogram-based training
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* \author Philip Cho, Tianqi Chen
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*/
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#ifndef XGBOOST_TREE_FAST_HIST_PARAM_H_
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#define XGBOOST_TREE_FAST_HIST_PARAM_H_
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namespace xgboost {
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namespace tree {
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/*! \brief training parameters for histogram-based training */
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struct FastHistParam : public dmlc::Parameter<FastHistParam> {
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int colmat_dtype;
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// percentage threshold for treating a feature as sparse
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// e.g. 0.2 indicates a feature with fewer than 20% nonzeros is considered sparse
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double sparse_threshold;
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// use feature grouping? (default yes)
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int enable_feature_grouping;
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// when grouping features, how many "conflicts" to allow.
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// conflict is when an instance has nonzero values for two or more features
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// default is 0, meaning features should be strictly complementary
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double max_conflict_rate;
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// when grouping features, how much effort to expend to prevent singleton groups
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// we'll try to insert each feature into existing groups before creating a new group
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// for that feature; to save time, only up to (max_search_group) of existing groups
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// will be considered. If set to zero, ALL existing groups will be examined
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unsigned max_search_group;
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// declare the parameters
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DMLC_DECLARE_PARAMETER(FastHistParam) {
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DMLC_DECLARE_FIELD(sparse_threshold).set_range(0, 1.0).set_default(0.2)
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.describe("percentage threshold for treating a feature as sparse");
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DMLC_DECLARE_FIELD(enable_feature_grouping).set_lower_bound(0).set_default(0)
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.describe("if >0, enable feature grouping to ameliorate work imbalance "
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"among worker threads");
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DMLC_DECLARE_FIELD(max_conflict_rate).set_range(0, 1.0).set_default(0)
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.describe("when grouping features, how many \"conflicts\" to allow."
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"conflict is when an instance has nonzero values for two or more features."
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"default is 0, meaning features should be strictly complementary.");
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DMLC_DECLARE_FIELD(max_search_group).set_lower_bound(0).set_default(100)
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.describe("when grouping features, how much effort to expend to prevent "
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"singleton groups. We'll try to insert each feature into existing "
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"groups before creating a new group for that feature; to save time, "
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"only up to (max_search_group) of existing groups will be "
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"considered. If set to zero, ALL existing groups will be examined.");
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}
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};
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} // namespace tree
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} // namespace xgboost
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#endif // XGBOOST_TREE_FAST_HIST_PARAM_H_
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