zhiqiang-hhhh commented on code in PR #40945: URL: https://github.com/apache/doris/pull/40945#discussion_r1768061359
########## be/src/vec/aggregate_functions/moments.h: ########## @@ -0,0 +1,112 @@ +// 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. + +#pragma once + +#include <stddef.h> + +#include "common/exception.h" +#include "common/status.h" +#include "vec/io/io_helper.h" + +namespace doris::vectorized { + +class BufferReadable; +class BufferWritable; + +template <typename T, size_t _level> +struct VarMoments { + // m[1] = sum(x) + // m[2] = sum(x^2) + // m[3] = sum(x^3) + // m[4] = sum(x^4) + T m[_level + 1] {}; + + void add(T x) { + ++m[0]; + m[1] += x; + m[2] += x * x; + if constexpr (_level >= 3) m[3] += x * x * x; + if constexpr (_level >= 4) m[4] += x * x * x * x; + } + + void merge(const VarMoments& rhs) { + m[0] += rhs.m[0]; + m[1] += rhs.m[1]; + m[2] += rhs.m[2]; + if constexpr (_level >= 3) m[3] += rhs.m[3]; + if constexpr (_level >= 4) m[4] += rhs.m[4]; + } + + void write(BufferWritable& buf) const { write_binary(*this, buf); } + + void read(BufferReadable& buf) { read_binary(*this, buf); } + + T get() const { + throw doris::Exception(ErrorCode::INTERNAL_ERROR, + "Variation moments should be obtained by either 'getSample' or " + "'getPopulation' method"); + } + + T getPopulation() const { + if (m[0] == 0) return std::numeric_limits<T>::quiet_NaN(); + + /// Due to numerical errors, the result can be slightly less than zero, + /// but it should be impossible. Trim to zero. + + return std::max(T {}, (m[2] - m[1] * m[1] / m[0]) / m[0]); + } + + T getSample() const { + if (m[0] <= 1) return std::numeric_limits<T>::quiet_NaN(); + return std::max(T {}, (m[2] - m[1] * m[1] / m[0]) / (m[0] - 1)); + } + + T getMoment3() const { + if constexpr (_level < 3) { + throw doris::Exception(ErrorCode::INTERNAL_ERROR, + "Variation moments should be obtained by either 'getSample' or " + "'getPopulation' method"); + } else { + if (m[0] == 0) return std::numeric_limits<T>::quiet_NaN(); + // to avoid accuracy problem + if (m[0] == 1) return 0; + /// \[ \frac{1}{m_0} (m_3 - (3 * m_2 - \frac{2 * {m_1}^2}{m_0}) * \frac{m_1}{m_0});\] + return (m[3] - (3 * m[2] - 2 * m[1] * m[1] / m[0]) * m[1] / m[0]) / m[0]; + } + } + + T getMoment4() const { + if constexpr (_level < 4) { + throw doris::Exception(ErrorCode::INTERNAL_ERROR, + "Variation moments should be obtained by either 'getSample' or " + "'getPopulation' method"); + } else { + if (m[0] == 0) return std::numeric_limits<T>::quiet_NaN(); + // to avoid accuracy problem + if (m[0] == 1) return 0; + /// \[ \frac{1}{m_0}(m_4 - (4 * m_3 - (6 * m_2 - \frac{3 * m_1^2}{m_0} ) \frac{m_1}{m_0})\frac{m_1}{m_0})\] + return (m[4] - + (4 * m[3] - (6 * m[2] - 3 * m[1] * m[1] / m[0]) * m[1] / m[0]) * m[1] / m[0]) / + m[0]; + } + } + + void reset() { return; } Review Comment: done -- 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: commits-unsubscr...@doris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
