wrlcke commented on code in PR #60833: URL: https://github.com/apache/doris/pull/60833#discussion_r2931761334
########## be/src/exprs/aggregate/aggregate_function_entropy.h: ########## @@ -0,0 +1,191 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. +// This file is copied from +// https://github.com/ClickHouse/ClickHouse/blob/master/src/AggregateFunctions/AggregateFunctionEntropy.cpp +// and modified by Doris + +#pragma once + +#include "core/assert_cast.h" +#include "core/column/column.h" +#include "core/column/column_decimal.h" +#include "core/data_type/data_type.h" +#include "core/data_type/data_type_number.h" +#include "core/string_ref.h" +#include "core/types.h" +#include "core/uint128.h" +#include "exec/common/hash_table/hash.h" +#include "exec/common/hash_table/phmap_fwd_decl.h" +#include "exprs/aggregate/aggregate_function.h" + +namespace doris { +#include "common/compile_check_begin.h" + +class Arena; +class BufferReadable; +class BufferWritable; +template <PrimitiveType> +class ColumnVector; + +/** Calculates Shannon Entropy, using HashMap and computing empirical distribution function. + * Entropy is measured in bits (base-2 logarithm is used). + */ +template <typename Value, typename Hash = HashCRC32<Value>> +struct AggregateFunctionEntropyData { + using Container = flat_hash_map<Value, uint64_t, Hash>; + using Self = AggregateFunctionEntropyData<Value, Hash>; + Container frequency_map; + + void clear() { frequency_map.clear(); } + + void add(const Value& elem) { ++frequency_map[elem]; } + + void merge(const Self& rhs) { + frequency_map.reserve(frequency_map.size() + rhs.frequency_map.size()); + for (const auto& [elem, count] : rhs.frequency_map) { + frequency_map[elem] += count; + } + } + + void write(BufferWritable& buf) const { + buf.write_var_uint(frequency_map.size()); + for (const auto& [elem, count] : frequency_map) { + buf.write_binary(elem); + buf.write_binary(count); + } + } + + void read(BufferReadable& buf) { + uint64_t new_size = 0; + buf.read_var_uint(new_size); + frequency_map.reserve(frequency_map.size() + new_size); + + Value elem; + uint64_t count; + for (size_t i = 0; i < new_size; ++i) { + buf.read_binary(elem); + buf.read_binary(count); + frequency_map[elem] += count; + } + } + + Float64 get_result() const { + Float64 entropy = 0; + uint64_t total_count = 0; + for (const auto& [_, count] : frequency_map) { + total_count += count; + } + for (const auto& [_, count] : frequency_map) { + Float64 p = static_cast<Float64>(count) / static_cast<Float64>(total_count); + entropy -= p * std::log2(p); + } + return entropy; + } + + static String get_name() { return "entropy"; } +}; + +template <PrimitiveType T> +struct AggregateFunctionEntropySingleNumericData + : public AggregateFunctionEntropyData<typename PrimitiveTypeTraits<T>::CppType> { + using Base = AggregateFunctionEntropyData<typename PrimitiveTypeTraits<T>::CppType>; + + void add(const IColumn** columns, size_t /* columns_num */, size_t row_num, Arena&) { + const auto& vec = assert_cast<const typename PrimitiveTypeTraits<T>::ColumnType&, + TypeCheckOnRelease::DISABLE>(*columns[0]) + .get_data(); + Base::add(vec[row_num]); + } +}; + +struct AggregateFunctionEntropySingleStringData + : public AggregateFunctionEntropyData<UInt128, UInt128TrivialHash> { + using Base = AggregateFunctionEntropyData<UInt128, UInt128TrivialHash>; + + void add(const IColumn** columns, size_t /* columns_num */, size_t row_num, Arena&) { + auto key = columns[0]->get_data_at(row_num); + auto hash_value = XXH_INLINE_XXH128(key.data, key.size, 0); + Base::add(UInt128 {hash_value.high64, hash_value.low64}); + } +}; + +struct AggregateFunctionEntropyGenericData + : public AggregateFunctionEntropyData<UInt128, UInt128TrivialHash> { + using Base = AggregateFunctionEntropyData<UInt128, UInt128TrivialHash>; + + void add(const IColumn** columns, size_t columns_num, size_t row_num, Arena& arena) { + const char* begin = nullptr; + StringRef key(begin, 0); + for (size_t i = 0; i < columns_num; ++i) { + auto cur_ref = columns[i]->serialize_value_into_arena(row_num, arena, begin); + key.data = cur_ref.data - key.size; + key.size += cur_ref.size; + } + auto hash_value = XXH_INLINE_XXH128(key.data, key.size, 0); + Base::add(UInt128 {hash_value.high64, hash_value.low64}); + } +}; + +template <typename Data> +class AggregateFunctionEntropy + : public IAggregateFunctionDataHelper<Data, AggregateFunctionEntropy<Data>>, Review Comment: ok ########## be/src/exprs/aggregate/aggregate_function_entropy.h: ########## @@ -0,0 +1,191 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. +// This file is copied from +// https://github.com/ClickHouse/ClickHouse/blob/master/src/AggregateFunctions/AggregateFunctionEntropy.cpp +// and modified by Doris + +#pragma once + +#include "core/assert_cast.h" +#include "core/column/column.h" +#include "core/column/column_decimal.h" +#include "core/data_type/data_type.h" +#include "core/data_type/data_type_number.h" +#include "core/string_ref.h" +#include "core/types.h" +#include "core/uint128.h" +#include "exec/common/hash_table/hash.h" +#include "exec/common/hash_table/phmap_fwd_decl.h" +#include "exprs/aggregate/aggregate_function.h" + +namespace doris { +#include "common/compile_check_begin.h" + +class Arena; +class BufferReadable; +class BufferWritable; +template <PrimitiveType> +class ColumnVector; + +/** Calculates Shannon Entropy, using HashMap and computing empirical distribution function. + * Entropy is measured in bits (base-2 logarithm is used). + */ +template <typename Value, typename Hash = HashCRC32<Value>> +struct AggregateFunctionEntropyData { + using Container = flat_hash_map<Value, uint64_t, Hash>; + using Self = AggregateFunctionEntropyData<Value, Hash>; + Container frequency_map; + + void clear() { frequency_map.clear(); } + + void add(const Value& elem) { ++frequency_map[elem]; } + + void merge(const Self& rhs) { + frequency_map.reserve(frequency_map.size() + rhs.frequency_map.size()); + for (const auto& [elem, count] : rhs.frequency_map) { + frequency_map[elem] += count; + } + } + + void write(BufferWritable& buf) const { + buf.write_var_uint(frequency_map.size()); + for (const auto& [elem, count] : frequency_map) { + buf.write_binary(elem); + buf.write_binary(count); + } + } + + void read(BufferReadable& buf) { + uint64_t new_size = 0; + buf.read_var_uint(new_size); + frequency_map.reserve(frequency_map.size() + new_size); + + Value elem; + uint64_t count; + for (size_t i = 0; i < new_size; ++i) { + buf.read_binary(elem); + buf.read_binary(count); + frequency_map[elem] += count; + } + } + + Float64 get_result() const { + Float64 entropy = 0; Review Comment: The performance impact is negligible, so it’s not necessary to switch to a less intuitive formula. ########## be/src/exprs/aggregate/aggregate_function_entropy.h: ########## @@ -0,0 +1,191 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. +// This file is copied from +// https://github.com/ClickHouse/ClickHouse/blob/master/src/AggregateFunctions/AggregateFunctionEntropy.cpp +// and modified by Doris + +#pragma once + +#include "core/assert_cast.h" +#include "core/column/column.h" +#include "core/column/column_decimal.h" +#include "core/data_type/data_type.h" +#include "core/data_type/data_type_number.h" +#include "core/string_ref.h" +#include "core/types.h" +#include "core/uint128.h" +#include "exec/common/hash_table/hash.h" +#include "exec/common/hash_table/phmap_fwd_decl.h" +#include "exprs/aggregate/aggregate_function.h" + +namespace doris { +#include "common/compile_check_begin.h" + +class Arena; +class BufferReadable; +class BufferWritable; +template <PrimitiveType> +class ColumnVector; + +/** Calculates Shannon Entropy, using HashMap and computing empirical distribution function. + * Entropy is measured in bits (base-2 logarithm is used). + */ +template <typename Value, typename Hash = HashCRC32<Value>> +struct AggregateFunctionEntropyData { + using Container = flat_hash_map<Value, uint64_t, Hash>; + using Self = AggregateFunctionEntropyData<Value, Hash>; + Container frequency_map; + + void clear() { frequency_map.clear(); } + + void add(const Value& elem) { ++frequency_map[elem]; } + + void merge(const Self& rhs) { + frequency_map.reserve(frequency_map.size() + rhs.frequency_map.size()); + for (const auto& [elem, count] : rhs.frequency_map) { + frequency_map[elem] += count; + } + } + + void write(BufferWritable& buf) const { + buf.write_var_uint(frequency_map.size()); + for (const auto& [elem, count] : frequency_map) { + buf.write_binary(elem); + buf.write_binary(count); + } + } + + void read(BufferReadable& buf) { + uint64_t new_size = 0; + buf.read_var_uint(new_size); + frequency_map.reserve(frequency_map.size() + new_size); + + Value elem; + uint64_t count; + for (size_t i = 0; i < new_size; ++i) { + buf.read_binary(elem); + buf.read_binary(count); + frequency_map[elem] += count; + } + } + + Float64 get_result() const { + Float64 entropy = 0; + uint64_t total_count = 0; + for (const auto& [_, count] : frequency_map) { + total_count += count; + } + for (const auto& [_, count] : frequency_map) { + Float64 p = static_cast<Float64>(count) / static_cast<Float64>(total_count); + entropy -= p * std::log2(p); + } + return entropy; + } + + static String get_name() { return "entropy"; } +}; + +template <PrimitiveType T> +struct AggregateFunctionEntropySingleNumericData + : public AggregateFunctionEntropyData<typename PrimitiveTypeTraits<T>::CppType> { + using Base = AggregateFunctionEntropyData<typename PrimitiveTypeTraits<T>::CppType>; + + void add(const IColumn** columns, size_t /* columns_num */, size_t row_num, Arena&) { + const auto& vec = assert_cast<const typename PrimitiveTypeTraits<T>::ColumnType&, + TypeCheckOnRelease::DISABLE>(*columns[0]) + .get_data(); + Base::add(vec[row_num]); + } +}; + +struct AggregateFunctionEntropySingleStringData + : public AggregateFunctionEntropyData<UInt128, UInt128TrivialHash> { + using Base = AggregateFunctionEntropyData<UInt128, UInt128TrivialHash>; + + void add(const IColumn** columns, size_t /* columns_num */, size_t row_num, Arena&) { + auto key = columns[0]->get_data_at(row_num); + auto hash_value = XXH_INLINE_XXH128(key.data, key.size, 0); Review Comment: For numeric keys the key itself is used as the hash table key, and CRC32 is used as the hash inside the hash table. For string and multi‑column keys this code path use XXH128 to produce a 128‑bit key representation that becomes the actual hash‑table key. This 128‑bit value should be effectively collision‑free in practice, so replacing it with CRC32C would be less safe. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
