4c74336384
* Use feature interaction constraints to narrow search space for split candidates. * fix clang-tidy broken at updater_quantile_hist.cc:535:3 * make const * fix * try to fix exception thrown in java_test * fix suspected mistake which cause EvaluateSplit error * try fix * Fix bug: feature ID and node ID swapped in argument * Rename CheckValidation() to CheckFeatureConstraint() for clarity * Do not create temporary vector validFeatures, to enable parallelism
104 lines
3.5 KiB
C++
104 lines
3.5 KiB
C++
/*!
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* Copyright 2018 by Contributors
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* \file split_evaluator.h
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* \brief Used for implementing a loss term specific to decision trees. Useful for custom regularisation.
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* \author Henry Gouk
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*/
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#ifndef XGBOOST_TREE_SPLIT_EVALUATOR_H_
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#define XGBOOST_TREE_SPLIT_EVALUATOR_H_
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#include <dmlc/registry.h>
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#include <xgboost/base.h>
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#include <functional>
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#include <memory>
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#include <string>
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#include <utility>
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#include <vector>
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#define ROOT_PARENT_ID (-1 & ((1U << 31) - 1))
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namespace xgboost {
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namespace tree {
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// Should GradStats be in this header, rather than param.h?
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struct GradStats;
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class SplitEvaluator {
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public:
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// Factory method for constructing new SplitEvaluators
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static SplitEvaluator* Create(const std::string& name);
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virtual ~SplitEvaluator() = default;
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// Used to initialise any regularisation hyperparameters provided by the user
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virtual void Init(
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const std::vector<std::pair<std::string, std::string> >& args);
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// Resets the SplitEvaluator to the state it was in after the Init was called
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virtual void Reset();
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// This will create a clone of the SplitEvaluator in host memory
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virtual SplitEvaluator* GetHostClone() const = 0;
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// Computes the score (negative loss) resulting from performing this split
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virtual bst_float ComputeSplitScore(bst_uint nodeid,
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bst_uint featureid,
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const GradStats& left_stats,
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const GradStats& right_stats,
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bst_float left_weight,
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bst_float right_weight) const = 0;
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virtual bst_float ComputeSplitScore(bst_uint nodeid,
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bst_uint featureid,
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const GradStats& left_stats,
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const GradStats& right_stats) const;
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// Compute the Score for a node with the given stats
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virtual bst_float ComputeScore(bst_uint parentid,
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const GradStats &stats,
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bst_float weight) const = 0;
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// Compute the weight for a node with the given stats
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virtual bst_float ComputeWeight(bst_uint parentid, const GradStats& stats)
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const = 0;
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virtual void AddSplit(bst_uint nodeid,
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bst_uint leftid,
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bst_uint rightid,
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bst_uint featureid,
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bst_float leftweight,
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bst_float rightweight);
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// Check whether a given feature is feasible for a given node.
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// Use this function to narrow the search space for split candidates
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virtual bool CheckFeatureConstraint(bst_uint nodeid,
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bst_uint featureid) const = 0;
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};
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struct SplitEvaluatorReg
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: public dmlc::FunctionRegEntryBase<SplitEvaluatorReg,
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std::function<SplitEvaluator* (std::unique_ptr<SplitEvaluator>)> > {};
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/*!
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* \brief Macro to register tree split evaluator.
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*
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* \code
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* // example of registering a split evaluator
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* XGBOOST_REGISTER_SPLIT_EVALUATOR(SplitEval, "splitEval")
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* .describe("Some split evaluator")
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* .set_body([]() {
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* return new SplitEval();
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* });
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* \endcode
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*/
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#define XGBOOST_REGISTER_SPLIT_EVALUATOR(UniqueID, Name) \
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static DMLC_ATTRIBUTE_UNUSED ::xgboost::tree::SplitEvaluatorReg& \
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__make_ ## SplitEvaluatorReg ## _ ## UniqueID ## __ = \
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::dmlc::Registry< ::xgboost::tree::SplitEvaluatorReg>::Get()->__REGISTER__(Name) //NOLINT
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} // namespace tree
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} // namespace xgboost
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#endif // XGBOOST_TREE_SPLIT_EVALUATOR_H_
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