mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-22 07:31:57 +00:00
Make the code less bad
This commit is contained in:
parent
90dcc135b4
commit
911cd77c1a
@ -8,6 +8,7 @@
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#include <IO/ReadHelpers.h>
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#include <AggregateFunctions/IAggregateFunction.h>
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#include <AggregateFunctions/Moments.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <DataTypes/DataTypesDecimal.h>
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@ -30,310 +31,6 @@
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int DECIMAL_OVERFLOW;
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}
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/**
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Calculating univariate central moments
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Levels:
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level 2 (pop & samp): var, stddev
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level 3: skewness
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level 4: kurtosis
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References:
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https://en.wikipedia.org/wiki/Moment_(mathematics)
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https://en.wikipedia.org/wiki/Skewness
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https://en.wikipedia.org/wiki/Kurtosis
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*/
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template <typename T, size_t _level>
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struct VarMoments
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{
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T m[_level + 1]{};
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void add(T x)
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{
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++m[0];
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m[1] += x;
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m[2] += x * x;
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if constexpr (_level >= 3) m[3] += x * x * x;
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if constexpr (_level >= 4) m[4] += x * x * x * x;
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}
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void merge(const VarMoments & rhs)
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{
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m[0] += rhs.m[0];
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m[1] += rhs.m[1];
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m[2] += rhs.m[2];
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if constexpr (_level >= 3) m[3] += rhs.m[3];
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if constexpr (_level >= 4) m[4] += rhs.m[4];
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}
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void write(WriteBuffer & buf) const
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{
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writePODBinary(*this, buf);
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}
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void read(ReadBuffer & buf)
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{
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readPODBinary(*this, buf);
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}
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T getPopulation() const
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{
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if (m[0] == 0)
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return std::numeric_limits<T>::quiet_NaN();
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/// Due to numerical errors, the result can be slightly less than zero,
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/// but it should be impossible. Trim to zero.
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return std::max(T{}, (m[2] - m[1] * m[1] / m[0]) / m[0]);
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}
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T getSample() const
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{
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if (m[0] <= 1)
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return std::numeric_limits<T>::quiet_NaN();
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return std::max(T{}, (m[2] - m[1] * m[1] / m[0]) / (m[0] - 1));
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}
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T getMoment3() const
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{
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if (m[0] == 0)
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return std::numeric_limits<T>::quiet_NaN();
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// to avoid accuracy problem
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if (m[0] == 1)
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return 0;
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return (m[3]
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- (3 * m[2]
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- 2 * m[1] * m[1] / m[0]
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) * m[1] / m[0]
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) / m[0];
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}
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T getMoment4() const
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{
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if (m[0] == 0)
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return std::numeric_limits<T>::quiet_NaN();
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// to avoid accuracy problem
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if (m[0] == 1)
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return 0;
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return (m[4]
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- (4 * m[3]
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- (6 * m[2]
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- 3 * m[1] * m[1] / m[0]
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) * m[1] / m[0]
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) * m[1] / m[0]
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) / m[0];
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}
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};
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template <typename T, size_t _level>
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class VarMomentsDecimal
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{
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public:
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using NativeType = typename T::NativeType;
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void add(NativeType x)
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{
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++m0;
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getM(1) += x;
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NativeType tmp;
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bool overflow = common::mulOverflow(x, x, tmp) || common::addOverflow(getM(2), tmp, getM(2));
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if constexpr (_level >= 3)
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overflow = overflow || common::mulOverflow(tmp, x, tmp) || common::addOverflow(getM(3), tmp, getM(3));
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if constexpr (_level >= 4)
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overflow = overflow || common::mulOverflow(tmp, x, tmp) || common::addOverflow(getM(4), tmp, getM(4));
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if (overflow)
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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}
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void merge(const VarMomentsDecimal & rhs)
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{
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m0 += rhs.m0;
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getM(1) += rhs.getM(1);
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bool overflow = common::addOverflow(getM(2), rhs.getM(2), getM(2));
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if constexpr (_level >= 3)
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overflow = overflow || common::addOverflow(getM(3), rhs.getM(3), getM(3));
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if constexpr (_level >= 4)
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overflow = overflow || common::addOverflow(getM(4), rhs.getM(4), getM(4));
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if (overflow)
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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}
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void write(WriteBuffer & buf) const { writePODBinary(*this, buf); }
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void read(ReadBuffer & buf) { readPODBinary(*this, buf); }
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Float64 getPopulation(UInt32 scale) const
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{
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if (m0 == 0)
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return std::numeric_limits<Float64>::infinity();
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NativeType tmp;
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if (common::mulOverflow(getM(1), getM(1), tmp) ||
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common::subOverflow(getM(2), NativeType(tmp / m0), tmp))
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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return std::max(Float64{}, DecimalUtils::convertTo<Float64>(T(tmp / m0), scale));
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}
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Float64 getSample(UInt32 scale) const
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{
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if (m0 == 0)
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return std::numeric_limits<Float64>::quiet_NaN();
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if (m0 == 1)
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return std::numeric_limits<Float64>::infinity();
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NativeType tmp;
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if (common::mulOverflow(getM(1), getM(1), tmp) ||
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common::subOverflow(getM(2), NativeType(tmp / m0), tmp))
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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return std::max(Float64{}, DecimalUtils::convertTo<Float64>(T(tmp / (m0 - 1)), scale));
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}
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Float64 getMoment3(UInt32 scale) const
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{
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if (m0 == 0)
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return std::numeric_limits<Float64>::infinity();
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NativeType tmp;
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if (common::mulOverflow(2 * getM(1), getM(1), tmp) ||
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common::subOverflow(3 * getM(2), NativeType(tmp / m0), tmp) ||
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common::mulOverflow(tmp, getM(1), tmp) ||
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common::subOverflow(getM(3), NativeType(tmp / m0), tmp))
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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return DecimalUtils::convertTo<Float64>(T(tmp / m0), scale);
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}
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Float64 getMoment4(UInt32 scale) const
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{
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if (m0 == 0)
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return std::numeric_limits<Float64>::infinity();
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NativeType tmp;
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if (common::mulOverflow(3 * getM(1), getM(1), tmp) ||
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common::subOverflow(6 * getM(2), NativeType(tmp / m0), tmp) ||
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common::mulOverflow(tmp, getM(1), tmp) ||
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common::subOverflow(4 * getM(3), NativeType(tmp / m0), tmp) ||
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common::mulOverflow(tmp, getM(1), tmp) ||
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common::subOverflow(getM(4), NativeType(tmp / m0), tmp))
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throw Exception("Decimal math overflow", ErrorCodes::DECIMAL_OVERFLOW);
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return DecimalUtils::convertTo<Float64>(T(tmp / m0), scale);
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}
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private:
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UInt64 m0{};
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NativeType m[_level]{};
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NativeType & getM(size_t i) { return m[i - 1]; }
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const NativeType & getM(size_t i) const { return m[i - 1]; }
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};
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/**
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Calculating multivariate central moments
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Levels:
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level 2 (pop & samp): covar
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References:
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https://en.wikipedia.org/wiki/Moment_(mathematics)
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*/
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template <typename T>
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struct CovarMoments
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{
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T m0{};
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T x1{};
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T y1{};
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T xy{};
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void add(T x, T y)
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{
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++m0;
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x1 += x;
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y1 += y;
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xy += x * y;
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}
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void merge(const CovarMoments & rhs)
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{
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m0 += rhs.m0;
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x1 += rhs.x1;
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y1 += rhs.y1;
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xy += rhs.xy;
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}
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void write(WriteBuffer & buf) const
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{
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writePODBinary(*this, buf);
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}
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void read(ReadBuffer & buf)
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{
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readPODBinary(*this, buf);
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}
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T NO_SANITIZE_UNDEFINED getPopulation() const
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{
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return (xy - x1 * y1 / m0) / m0;
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}
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T NO_SANITIZE_UNDEFINED getSample() const
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{
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if (m0 == 0)
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return std::numeric_limits<T>::quiet_NaN();
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return (xy - x1 * y1 / m0) / (m0 - 1);
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}
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};
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template <typename T>
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struct CorrMoments
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{
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T m0{};
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T x1{};
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T y1{};
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T xy{};
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T x2{};
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T y2{};
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void add(T x, T y)
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{
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++m0;
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x1 += x;
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y1 += y;
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xy += x * y;
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x2 += x * x;
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y2 += y * y;
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}
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void merge(const CorrMoments & rhs)
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{
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m0 += rhs.m0;
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x1 += rhs.x1;
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y1 += rhs.y1;
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xy += rhs.xy;
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x2 += rhs.x2;
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y2 += rhs.y2;
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}
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void write(WriteBuffer & buf) const
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{
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writePODBinary(*this, buf);
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}
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void read(ReadBuffer & buf)
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{
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readPODBinary(*this, buf);
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}
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T NO_SANITIZE_UNDEFINED get() const
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{
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return (m0 * xy - x1 * y1) / sqrt((m0 * x2 - x1 * x1) * (m0 * y2 - y1 * y1));
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}
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};
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enum class StatisticsFunctionKind
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{
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varPop, varSamp,
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@ -1,52 +1,70 @@
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#include <AggregateFunctions/AggregateFunctionFactory.h>
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#include <AggregateFunctions/AggregateFunctionStudentTTest.h>
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#include <AggregateFunctions/AggregateFunctionTTest.h>
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#include <AggregateFunctions/FactoryHelpers.h>
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#include <AggregateFunctions/Moments.h>
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#include "registerAggregateFunctions.h"
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#include <AggregateFunctions/Helpers.h>
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#include <DataTypes/DataTypeAggregateFunction.h>
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// the return type is boolean (we use UInt8 as we do not have boolean in clickhouse)
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namespace ErrorCodes
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{
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extern const int NOT_IMPLEMENTED;
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extern const int BAD_ARGUMENTS;
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}
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namespace DB
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{
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namespace
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{
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struct StudentTTestData : public TTestMoments<Float64>
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{
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static constexpr auto name = "studentTTest";
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std::pair<Float64, Float64> getResult() const
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{
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Float64 degrees_of_freedom = 2.0 * (m0 - 1);
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Float64 mean_x = x1 / m0;
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Float64 mean_y = y1 / m0;
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/// Calculate s^2
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/// The original formulae looks like
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/// \frac{\sum_{i = 1}^{n_x}{(x_i - \bar{x}) ^ 2} + \sum_{i = 1}^{n_y}{(y_i - \bar{y}) ^ 2}}{n_x + n_y - 2}
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/// But we made some mathematical transformations not to store original sequences.
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/// Also we dropped sqrt, because later it will be squared later.
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Float64 all_x = x2 + m0 * mean_x * mean_x - 2 * mean_x * m0;
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Float64 all_y = y2 + m0 * mean_y * mean_y - 2 * mean_y * m0;
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Float64 s2 = (all_x + all_y) / degrees_of_freedom;
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Float64 std_err2 = 2.0 * s2 / m0;
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/// t-statistic, squared
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Float64 t_stat = (mean_x - mean_y) / sqrt(std_err2);
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return {t_stat, getPValue(degrees_of_freedom, t_stat * t_stat)};
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}
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};
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AggregateFunctionPtr createAggregateFunctionStudentTTest(const std::string & name, const DataTypes & argument_types, const Array & parameters)
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{
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assertBinary(name, argument_types);
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assertNoParameters(name, parameters);
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AggregateFunctionPtr res;
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if (!isNumber(argument_types[0]) || !isNumber(argument_types[1]))
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throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::BAD_ARGUMENTS);
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if (isDecimal(argument_types[0]) || isDecimal(argument_types[1]))
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{
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throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::NOT_IMPLEMENTED);
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}
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else
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{
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res.reset(createWithTwoNumericTypes<AggregateFunctionStudentTTest>(*argument_types[0], *argument_types[1], argument_types));
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}
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if (!res)
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{
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throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::NOT_IMPLEMENTED);
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}
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return res;
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return std::make_shared<AggregateFunctionTTest<StudentTTestData>>(argument_types);
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}
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}
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void registerAggregateFunctionStudentTTest(AggregateFunctionFactory & factory)
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{
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factory.registerFunction("studentTTest", createAggregateFunctionStudentTTest);
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}
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}
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@ -1,262 +0,0 @@
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#pragma once
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#include <AggregateFunctions/IAggregateFunction.h>
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#include <Columns/ColumnVector.h>
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#include <Columns/ColumnTuple.h>
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#include <Common/assert_cast.h>
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#include <Common/FieldVisitors.h>
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#include <Core/Types.h>
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#include <DataTypes/DataTypesDecimal.h>
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#include <DataTypes/DataTypeNullable.h>
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#include <DataTypes/DataTypesNumber.h>
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#include <DataTypes/DataTypeTuple.h>
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#include <IO/ReadHelpers.h>
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#include <IO/WriteHelpers.h>
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#include <limits>
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#include <cmath>
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#include <functional>
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#include <type_traits>
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namespace ErrorCodes
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{
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extern const int BAD_ARGUMENTS;
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}
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#if defined(OS_DARWIN)
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extern "C"
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{
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double lgammal_r(double x, int * signgamp);
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}
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#endif
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namespace DB
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{
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template <typename X = Float64, typename Y = Float64>
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struct AggregateFunctionStudentTTestData final
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{
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size_t size_x = 0;
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size_t size_y = 0;
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X sum_x = static_cast<X>(0);
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Y sum_y = static_cast<Y>(0);
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X square_sum_x = static_cast<X>(0);
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Y square_sum_y = static_cast<Y>(0);
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Float64 mean_x = static_cast<Float64>(0);
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Float64 mean_y = static_cast<Float64>(0);
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void add(X x, Y y)
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{
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sum_x += x;
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sum_y += y;
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size_x++;
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size_y++;
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mean_x = static_cast<Float64>(sum_x) / size_x;
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mean_y = static_cast<Float64>(sum_y) / size_y;
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square_sum_x += x * x;
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square_sum_y += y * y;
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}
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void merge(const AggregateFunctionStudentTTestData &other)
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{
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sum_x += other.sum_x;
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sum_y += other.sum_y;
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size_x += other.size_x;
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size_y += other.size_y;
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mean_x = static_cast<Float64>(sum_x) / size_x;
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mean_y = static_cast<Float64>(sum_y) / size_y;
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square_sum_x += other.square_sum_x;
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square_sum_y += other.square_sum_y;
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}
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void serialize(WriteBuffer &buf) const
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{
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writeBinary(mean_x, buf);
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writeBinary(mean_y, buf);
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writeBinary(sum_x, buf);
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writeBinary(sum_y, buf);
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writeBinary(square_sum_x, buf);
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writeBinary(square_sum_y, buf);
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writeBinary(size_x, buf);
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writeBinary(size_y, buf);
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||||
}
|
||||
|
||||
void deserialize(ReadBuffer &buf)
|
||||
{
|
||||
readBinary(mean_x, buf);
|
||||
readBinary(mean_y, buf);
|
||||
readBinary(sum_x, buf);
|
||||
readBinary(sum_y, buf);
|
||||
readBinary(square_sum_x, buf);
|
||||
readBinary(square_sum_y, buf);
|
||||
readBinary(size_x, buf);
|
||||
readBinary(size_y, buf);
|
||||
}
|
||||
|
||||
size_t getSizeY() const
|
||||
{
|
||||
return size_y;
|
||||
}
|
||||
|
||||
size_t getSizeX() const
|
||||
{
|
||||
return size_x;
|
||||
}
|
||||
|
||||
Float64 getSSquared() const
|
||||
{
|
||||
/// The original formulae looks like
|
||||
/// \frac{\sum_{i = 1}^{n_x}{(x_i - \bar{x}) ^ 2} + \sum_{i = 1}^{n_y}{(y_i - \bar{y}) ^ 2}}{n_x + n_y - 2}
|
||||
/// But we made some mathematical transformations not to store original sequences.
|
||||
/// Also we dropped sqrt, because later it will be squared later.
|
||||
const Float64 all_x = square_sum_x + size_x * std::pow(mean_x, 2) - 2 * mean_x * sum_x;
|
||||
const Float64 all_y = square_sum_y + size_y * std::pow(mean_y, 2) - 2 * mean_y * sum_y;
|
||||
return static_cast<Float64>(all_x + all_y) / (size_x + size_y - 2);
|
||||
}
|
||||
|
||||
|
||||
Float64 getTStatisticSquared() const
|
||||
{
|
||||
return std::pow(mean_x - mean_y, 2) / getStandartErrorSquared();
|
||||
}
|
||||
|
||||
Float64 getTStatistic() const
|
||||
{
|
||||
return (mean_x - mean_y) / std::sqrt(getStandartErrorSquared());
|
||||
}
|
||||
|
||||
Float64 getStandartErrorSquared() const
|
||||
{
|
||||
if (size_x == 0 || size_y == 0)
|
||||
throw Exception("Division by zero encountered in Aggregate function StudentTTest", ErrorCodes::BAD_ARGUMENTS);
|
||||
|
||||
return getSSquared() * (1.0 / static_cast<Float64>(size_x) + 1.0 / static_cast<Float64>(size_y));
|
||||
}
|
||||
|
||||
Float64 getDegreesOfFreedom() const
|
||||
{
|
||||
return static_cast<Float64>(size_x + size_y - 2);
|
||||
}
|
||||
|
||||
static Float64 integrateSimpson(Float64 a, Float64 b, std::function<Float64(Float64)> func)
|
||||
{
|
||||
const size_t iterations = std::max(1e6, 1e4 * std::abs(std::round(b)));
|
||||
const long double h = (b - a) / iterations;
|
||||
Float64 sum_odds = 0.0;
|
||||
for (size_t i = 1; i < iterations; i += 2)
|
||||
sum_odds += func(a + i * h);
|
||||
Float64 sum_evens = 0.0;
|
||||
for (size_t i = 2; i < iterations; i += 2)
|
||||
sum_evens += func(a + i * h);
|
||||
return (func(a) + func(b) + 2 * sum_evens + 4 * sum_odds) * h / 3;
|
||||
}
|
||||
|
||||
Float64 getPValue() const
|
||||
{
|
||||
const Float64 v = getDegreesOfFreedom();
|
||||
const Float64 t = getTStatisticSquared();
|
||||
auto f = [&v] (double x) { return std::pow(x, v/2 - 1) / std::sqrt(1 - x); };
|
||||
Float64 numenator = integrateSimpson(0, v / (t + v), f);
|
||||
int unused;
|
||||
Float64 denominator = std::exp(lgammal_r(v / 2, &unused) + lgammal_r(0.5, &unused) - lgammal_r(v / 2 + 0.5, &unused));
|
||||
return numenator / denominator;
|
||||
}
|
||||
|
||||
std::pair<Float64, Float64> getResult() const
|
||||
{
|
||||
return std::make_pair(getTStatistic(), getPValue());
|
||||
}
|
||||
};
|
||||
|
||||
/// Returns tuple of (t-statistic, p-value)
|
||||
/// https://cpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/9/1193/files/2016/01/05b-TandP.pdf
|
||||
template <typename X = Float64, typename Y = Float64>
|
||||
class AggregateFunctionStudentTTest :
|
||||
public IAggregateFunctionDataHelper<AggregateFunctionStudentTTestData<X, Y>,AggregateFunctionStudentTTest<X, Y>>
|
||||
{
|
||||
|
||||
public:
|
||||
AggregateFunctionStudentTTest(const DataTypes & arguments)
|
||||
: IAggregateFunctionDataHelper<AggregateFunctionStudentTTestData<X, Y>, AggregateFunctionStudentTTest<X, Y>> ({arguments}, {})
|
||||
{}
|
||||
|
||||
String getName() const override
|
||||
{
|
||||
return "studentTTest";
|
||||
}
|
||||
|
||||
DataTypePtr getReturnType() const override
|
||||
{
|
||||
DataTypes types
|
||||
{
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
};
|
||||
|
||||
Strings names
|
||||
{
|
||||
"t-statistic",
|
||||
"p-value"
|
||||
};
|
||||
|
||||
return std::make_shared<DataTypeTuple>(
|
||||
std::move(types),
|
||||
std::move(names)
|
||||
);
|
||||
}
|
||||
|
||||
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
|
||||
{
|
||||
auto col_x = assert_cast<const ColumnVector<X> *>(columns[0]);
|
||||
auto col_y = assert_cast<const ColumnVector<Y> *>(columns[1]);
|
||||
|
||||
X x = col_x->getData()[row_num];
|
||||
Y y = col_y->getData()[row_num];
|
||||
|
||||
this->data(place).add(x, y);
|
||||
}
|
||||
|
||||
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
|
||||
{
|
||||
this->data(place).merge(this->data(rhs));
|
||||
}
|
||||
|
||||
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
|
||||
{
|
||||
this->data(place).serialize(buf);
|
||||
}
|
||||
|
||||
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
|
||||
{
|
||||
this->data(place).deserialize(buf);
|
||||
}
|
||||
|
||||
void insertResultInto(AggregateDataPtr place, IColumn & to, Arena * /*arena*/) const override
|
||||
{
|
||||
size_t size_x = this->data(place).getSizeX();
|
||||
size_t size_y = this->data(place).getSizeY();
|
||||
|
||||
if (size_x < 2 || size_y < 2)
|
||||
{
|
||||
throw Exception("Aggregate function " + getName() + " requires samples to be of size > 1", ErrorCodes::BAD_ARGUMENTS);
|
||||
}
|
||||
|
||||
Float64 t_statistic = 0.0;
|
||||
Float64 p_value = 0.0;
|
||||
std::tie(t_statistic, p_value) = this->data(place).getResult();
|
||||
|
||||
/// Because p-value is a probability.
|
||||
p_value = std::min(1.0, std::max(0.0, p_value));
|
||||
|
||||
auto & column_tuple = assert_cast<ColumnTuple &>(to);
|
||||
auto & column_stat = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(0));
|
||||
auto & column_value = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(1));
|
||||
|
||||
column_stat.getData().push_back(t_statistic);
|
||||
column_value.getData().push_back(p_value);
|
||||
}
|
||||
|
||||
};
|
||||
|
||||
};
|
135
src/AggregateFunctions/AggregateFunctionTTest.h
Normal file
135
src/AggregateFunctions/AggregateFunctionTTest.h
Normal file
@ -0,0 +1,135 @@
|
||||
#pragma once
|
||||
|
||||
#include <AggregateFunctions/IAggregateFunction.h>
|
||||
#include <Columns/ColumnVector.h>
|
||||
#include <Columns/ColumnTuple.h>
|
||||
#include <Common/assert_cast.h>
|
||||
#include <Core/Types.h>
|
||||
#include <DataTypes/DataTypesNumber.h>
|
||||
#include <DataTypes/DataTypeTuple.h>
|
||||
#include <cmath>
|
||||
|
||||
|
||||
/// This function is used in implementations of different T-Tests.
|
||||
/// On Darwin it's unavailable in math.h but actually exists in the library (can be linked successfully).
|
||||
#if defined(OS_DARWIN)
|
||||
extern "C"
|
||||
{
|
||||
double lgamma_r(double x, int * signgamp);
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
namespace DB
|
||||
{
|
||||
|
||||
class ReadBuffer;
|
||||
class WriteBuffer;
|
||||
|
||||
|
||||
template <typename F>
|
||||
static Float64 integrateSimpson(Float64 a, Float64 b, F && func)
|
||||
{
|
||||
const size_t iterations = std::max(1e6, 1e4 * std::abs(std::round(b)));
|
||||
const long double h = (b - a) / iterations;
|
||||
Float64 sum_odds = 0.0;
|
||||
for (size_t i = 1; i < iterations; i += 2)
|
||||
sum_odds += func(a + i * h);
|
||||
Float64 sum_evens = 0.0;
|
||||
for (size_t i = 2; i < iterations; i += 2)
|
||||
sum_evens += func(a + i * h);
|
||||
return (func(a) + func(b) + 2 * sum_evens + 4 * sum_odds) * h / 3;
|
||||
}
|
||||
|
||||
static inline Float64 getPValue(Float64 degrees_of_freedom, Float64 t_stat2)
|
||||
{
|
||||
Float64 numerator = integrateSimpson(0, degrees_of_freedom / (t_stat2 + degrees_of_freedom),
|
||||
[degrees_of_freedom](double x) { return std::pow(x, degrees_of_freedom / 2 - 1) / std::sqrt(1 - x); });
|
||||
|
||||
int unused;
|
||||
Float64 denominator = std::exp(
|
||||
lgamma_r(degrees_of_freedom / 2, &unused)
|
||||
+ lgamma_r(0.5, &unused)
|
||||
- lgamma_r(degrees_of_freedom / 2 + 0.5, &unused));
|
||||
|
||||
return std::min(1.0, std::max(0.0, numerator / denominator));
|
||||
}
|
||||
|
||||
|
||||
/// Returns tuple of (t-statistic, p-value)
|
||||
/// https://cpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/9/1193/files/2016/01/05b-TandP.pdf
|
||||
template <typename Data>
|
||||
class AggregateFunctionTTest :
|
||||
public IAggregateFunctionDataHelper<Data, AggregateFunctionTTest<Data>>
|
||||
{
|
||||
public:
|
||||
AggregateFunctionTTest(const DataTypes & arguments)
|
||||
: IAggregateFunctionDataHelper<Data, AggregateFunctionTTest<Data>>({arguments}, {})
|
||||
{
|
||||
}
|
||||
|
||||
String getName() const override
|
||||
{
|
||||
return Data::name;
|
||||
}
|
||||
|
||||
DataTypePtr getReturnType() const override
|
||||
{
|
||||
DataTypes types
|
||||
{
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
};
|
||||
|
||||
Strings names
|
||||
{
|
||||
"t_statistic",
|
||||
"p_value"
|
||||
};
|
||||
|
||||
return std::make_shared<DataTypeTuple>(
|
||||
std::move(types),
|
||||
std::move(names)
|
||||
);
|
||||
}
|
||||
|
||||
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
|
||||
{
|
||||
Float64 x = columns[0]->getFloat64(row_num);
|
||||
Float64 y = columns[1]->getFloat64(row_num);
|
||||
|
||||
this->data(place).add(x, y);
|
||||
}
|
||||
|
||||
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
|
||||
{
|
||||
this->data(place).merge(this->data(rhs));
|
||||
}
|
||||
|
||||
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
|
||||
{
|
||||
this->data(place).write(buf);
|
||||
}
|
||||
|
||||
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
|
||||
{
|
||||
this->data(place).read(buf);
|
||||
}
|
||||
|
||||
void insertResultInto(AggregateDataPtr place, IColumn & to, Arena *) const override
|
||||
{
|
||||
auto [t_statistic, p_value] = this->data(place).getResult();
|
||||
|
||||
/// Because p-value is a probability.
|
||||
p_value = std::min(1.0, std::max(0.0, p_value));
|
||||
|
||||
auto & column_tuple = assert_cast<ColumnTuple &>(to);
|
||||
auto & column_stat = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(0));
|
||||
auto & column_value = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(1));
|
||||
|
||||
column_stat.getData().push_back(t_statistic);
|
||||
column_value.getData().push_back(p_value);
|
||||
}
|
||||
};
|
||||
|
||||
};
|
@ -1,49 +1,74 @@
|
||||
#include <AggregateFunctions/AggregateFunctionFactory.h>
|
||||
#include <AggregateFunctions/AggregateFunctionWelchTTest.h>
|
||||
#include <AggregateFunctions/AggregateFunctionTTest.h>
|
||||
#include <AggregateFunctions/FactoryHelpers.h>
|
||||
#include <AggregateFunctions/Moments.h>
|
||||
|
||||
#include "registerAggregateFunctions.h"
|
||||
|
||||
#include <AggregateFunctions/Helpers.h>
|
||||
#include <DataTypes/DataTypeAggregateFunction.h>
|
||||
|
||||
namespace ErrorCodes
|
||||
{
|
||||
extern const int NOT_IMPLEMENTED;
|
||||
extern const int BAD_ARGUMENTS;
|
||||
}
|
||||
|
||||
|
||||
namespace DB
|
||||
{
|
||||
|
||||
namespace
|
||||
{
|
||||
|
||||
struct WelchTTestData : public TTestMoments<Float64>
|
||||
{
|
||||
static constexpr auto name = "welchTTest";
|
||||
|
||||
std::pair<Float64, Float64> getResult() const
|
||||
{
|
||||
Float64 mean_x = x1 / m0;
|
||||
Float64 mean_y = y1 / m0;
|
||||
|
||||
/// s_x^2, s_y^2
|
||||
|
||||
/// The original formulae looks like \frac{1}{size_x - 1} \sum_{i = 1}^{size_x}{(x_i - \bar{x}) ^ 2}
|
||||
/// But we made some mathematical transformations not to store original sequences.
|
||||
/// Also we dropped sqrt, because later it will be squared later.
|
||||
|
||||
Float64 sx2 = (x2 + m0 * mean_x * mean_x - 2 * mean_x * x1) / (m0 - 1);
|
||||
Float64 sy2 = (y2 + m0 * mean_y * mean_y - 2 * mean_y * y1) / (m0 - 1);
|
||||
|
||||
/// t-statistic, squared
|
||||
Float64 t_stat = (mean_x - mean_y) / sqrt(sx2 / m0 + sy2 / m0);
|
||||
|
||||
/// degrees of freedom
|
||||
|
||||
Float64 numerator_sqrt = sx2 / m0 + sy2 / m0;
|
||||
Float64 numerator = numerator_sqrt * numerator_sqrt;
|
||||
|
||||
Float64 denominator_x = sx2 * sx2 / (m0 * m0 * (m0 - 1));
|
||||
Float64 denominator_y = sy2 * sy2 / (m0 * m0 * (m0 - 1));
|
||||
|
||||
Float64 degrees_of_freedom = numerator / (denominator_x + denominator_y);
|
||||
|
||||
return {t_stat, getPValue(degrees_of_freedom, t_stat * t_stat)};
|
||||
}
|
||||
};
|
||||
|
||||
AggregateFunctionPtr createAggregateFunctionWelchTTest(const std::string & name, const DataTypes & argument_types, const Array & parameters)
|
||||
{
|
||||
assertBinary(name, argument_types);
|
||||
assertNoParameters(name, parameters);
|
||||
|
||||
AggregateFunctionPtr res;
|
||||
if (!isNumber(argument_types[0]) || !isNumber(argument_types[1]))
|
||||
throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::BAD_ARGUMENTS);
|
||||
|
||||
if (isDecimal(argument_types[0]) || isDecimal(argument_types[1]))
|
||||
{
|
||||
throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::NOT_IMPLEMENTED);
|
||||
}
|
||||
else
|
||||
{
|
||||
res.reset(createWithTwoNumericTypes<AggregateFunctionWelchTTest>(*argument_types[0], *argument_types[1], argument_types));
|
||||
}
|
||||
|
||||
if (!res)
|
||||
{
|
||||
throw Exception("Aggregate function " + name + " only supports numerical types", ErrorCodes::NOT_IMPLEMENTED);
|
||||
}
|
||||
|
||||
return res;
|
||||
return std::make_shared<AggregateFunctionTTest<WelchTTestData>>(argument_types);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
void registerAggregateFunctionWelchTTest(AggregateFunctionFactory & factory)
|
||||
{
|
||||
factory.registerFunction("welchTTest", createAggregateFunctionWelchTTest);
|
||||
}
|
||||
|
||||
}
|
||||
|
@ -1,274 +0,0 @@
|
||||
#pragma once
|
||||
|
||||
#include <AggregateFunctions/IAggregateFunction.h>
|
||||
#include <Columns/ColumnVector.h>
|
||||
#include <Columns/ColumnTuple.h>
|
||||
#include <Common/assert_cast.h>
|
||||
#include <Common/FieldVisitors.h>
|
||||
#include <Core/Types.h>
|
||||
#include <DataTypes/DataTypesDecimal.h>
|
||||
#include <DataTypes/DataTypeNullable.h>
|
||||
#include <DataTypes/DataTypesNumber.h>
|
||||
#include <DataTypes/DataTypeTuple.h>
|
||||
#include <IO/ReadHelpers.h>
|
||||
#include <IO/WriteHelpers.h>
|
||||
#include <limits>
|
||||
#include <cmath>
|
||||
#include <functional>
|
||||
|
||||
#include <type_traits>
|
||||
|
||||
|
||||
namespace ErrorCodes
|
||||
{
|
||||
extern const int BAD_ARGUMENTS;
|
||||
}
|
||||
|
||||
#if defined(OS_DARWIN)
|
||||
extern "C"
|
||||
{
|
||||
double lgammal_r(double x, int * signgamp);
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
namespace DB
|
||||
{
|
||||
|
||||
template <typename X = Float64, typename Y = Float64>
|
||||
struct AggregateFunctionWelchTTestData final
|
||||
{
|
||||
size_t size_x = 0;
|
||||
size_t size_y = 0;
|
||||
X sum_x = static_cast<X>(0);
|
||||
Y sum_y = static_cast<Y>(0);
|
||||
X square_sum_x = static_cast<X>(0);
|
||||
Y square_sum_y = static_cast<Y>(0);
|
||||
Float64 mean_x = static_cast<Float64>(0);
|
||||
Float64 mean_y = static_cast<Float64>(0);
|
||||
|
||||
void add(X x, Y y)
|
||||
{
|
||||
sum_x += x;
|
||||
sum_y += y;
|
||||
size_x++;
|
||||
size_y++;
|
||||
mean_x = static_cast<Float64>(sum_x) / size_x;
|
||||
mean_y = static_cast<Float64>(sum_y) / size_y;
|
||||
square_sum_x += x * x;
|
||||
square_sum_y += y * y;
|
||||
}
|
||||
|
||||
void merge(const AggregateFunctionWelchTTestData &other)
|
||||
{
|
||||
sum_x += other.sum_x;
|
||||
sum_y += other.sum_y;
|
||||
size_x += other.size_x;
|
||||
size_y += other.size_y;
|
||||
mean_x = static_cast<Float64>(sum_x) / size_x;
|
||||
mean_y = static_cast<Float64>(sum_y) / size_y;
|
||||
square_sum_x += other.square_sum_x;
|
||||
square_sum_y += other.square_sum_y;
|
||||
}
|
||||
|
||||
void serialize(WriteBuffer &buf) const
|
||||
{
|
||||
writeBinary(mean_x, buf);
|
||||
writeBinary(mean_y, buf);
|
||||
writeBinary(sum_x, buf);
|
||||
writeBinary(sum_y, buf);
|
||||
writeBinary(square_sum_x, buf);
|
||||
writeBinary(square_sum_y, buf);
|
||||
writeBinary(size_x, buf);
|
||||
writeBinary(size_y, buf);
|
||||
}
|
||||
|
||||
void deserialize(ReadBuffer &buf)
|
||||
{
|
||||
readBinary(mean_x, buf);
|
||||
readBinary(mean_y, buf);
|
||||
readBinary(sum_x, buf);
|
||||
readBinary(sum_y, buf);
|
||||
readBinary(square_sum_x, buf);
|
||||
readBinary(square_sum_y, buf);
|
||||
readBinary(size_x, buf);
|
||||
readBinary(size_y, buf);
|
||||
}
|
||||
|
||||
size_t getSizeY() const
|
||||
{
|
||||
return size_y;
|
||||
}
|
||||
|
||||
size_t getSizeX() const
|
||||
{
|
||||
return size_x;
|
||||
}
|
||||
|
||||
Float64 getSxSquared() const
|
||||
{
|
||||
/// The original formulae looks like \frac{1}{size_x - 1} \sum_{i = 1}^{size_x}{(x_i - \bar{x}) ^ 2}
|
||||
/// But we made some mathematical transformations not to store original sequences.
|
||||
/// Also we dropped sqrt, because later it will be squared later.
|
||||
return static_cast<Float64>(square_sum_x + size_x * std::pow(mean_x, 2) - 2 * mean_x * sum_x) / (size_x - 1);
|
||||
}
|
||||
|
||||
Float64 getSySquared() const
|
||||
{
|
||||
/// The original formulae looks like \frac{1}{size_y - 1} \sum_{i = 1}^{size_y}{(y_i - \bar{y}) ^ 2}
|
||||
/// But we made some mathematical transformations not to store original sequences.
|
||||
/// Also we dropped sqrt, because later it will be squared later.
|
||||
return static_cast<Float64>(square_sum_y + size_y * std::pow(mean_y, 2) - 2 * mean_y * sum_y) / (size_y - 1);
|
||||
}
|
||||
|
||||
Float64 getTStatisticSquared() const
|
||||
{
|
||||
if (size_x == 0 || size_y == 0)
|
||||
{
|
||||
throw Exception("Division by zero encountered in Aggregate function WelchTTest", ErrorCodes::BAD_ARGUMENTS);
|
||||
}
|
||||
|
||||
return std::pow(mean_x - mean_y, 2) / (getSxSquared() / size_x + getSySquared() / size_y);
|
||||
}
|
||||
|
||||
Float64 getTStatistic() const
|
||||
{
|
||||
if (size_x == 0 || size_y == 0)
|
||||
{
|
||||
throw Exception("Division by zero encountered in Aggregate function WelchTTest", ErrorCodes::BAD_ARGUMENTS);
|
||||
}
|
||||
|
||||
return (mean_x - mean_y) / std::sqrt(getSxSquared() / size_x + getSySquared() / size_y);
|
||||
}
|
||||
|
||||
Float64 getDegreesOfFreedom() const
|
||||
{
|
||||
auto sx = getSxSquared();
|
||||
auto sy = getSySquared();
|
||||
Float64 numerator = std::pow(sx / size_x + sy / size_y, 2);
|
||||
Float64 denominator_first = std::pow(sx, 2) / (std::pow(size_x, 2) * (size_x - 1));
|
||||
Float64 denominator_second = std::pow(sy, 2) / (std::pow(size_y, 2) * (size_y - 1));
|
||||
return numerator / (denominator_first + denominator_second);
|
||||
}
|
||||
|
||||
static Float64 integrateSimpson(Float64 a, Float64 b, std::function<Float64(Float64)> func)
|
||||
{
|
||||
size_t iterations = std::max(1e6, 1e4 * std::abs(std::round(b)));
|
||||
double h = (b - a) / iterations;
|
||||
Float64 sum_odds = 0.0;
|
||||
for (size_t i = 1; i < iterations; i += 2)
|
||||
sum_odds += func(a + i * h);
|
||||
Float64 sum_evens = 0.0;
|
||||
for (size_t i = 2; i < iterations; i += 2)
|
||||
sum_evens += func(a + i * h);
|
||||
return (func(a) + func(b) + 2 * sum_evens + 4 * sum_odds) * h / 3;
|
||||
}
|
||||
|
||||
Float64 getPValue() const
|
||||
{
|
||||
const Float64 v = getDegreesOfFreedom();
|
||||
const Float64 t = getTStatisticSquared();
|
||||
auto f = [&v] (double x) { return std::pow(x, v / 2 - 1) / std::sqrt(1 - x); };
|
||||
Float64 numenator = integrateSimpson(0, v / (t + v), f);
|
||||
int unused;
|
||||
Float64 denominator = std::exp(lgammal_r(v / 2, &unused) + lgammal_r(0.5, &unused) - lgammal_r(v / 2 + 0.5, &unused));
|
||||
return numenator / denominator;
|
||||
}
|
||||
|
||||
std::pair<Float64, Float64> getResult() const
|
||||
{
|
||||
return std::make_pair(getTStatistic(), getPValue());
|
||||
}
|
||||
};
|
||||
|
||||
/// Returns tuple of (t-statistic, p-value)
|
||||
/// https://cpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/9/1193/files/2016/01/05b-TandP.pdf
|
||||
template <typename X = Float64, typename Y = Float64>
|
||||
class AggregateFunctionWelchTTest :
|
||||
public IAggregateFunctionDataHelper<AggregateFunctionWelchTTestData<X, Y>,AggregateFunctionWelchTTest<X, Y>>
|
||||
{
|
||||
|
||||
public:
|
||||
AggregateFunctionWelchTTest(const DataTypes & arguments)
|
||||
: IAggregateFunctionDataHelper<AggregateFunctionWelchTTestData<X, Y>, AggregateFunctionWelchTTest<X, Y>> ({arguments}, {})
|
||||
{}
|
||||
|
||||
String getName() const override
|
||||
{
|
||||
return "welchTTest";
|
||||
}
|
||||
|
||||
DataTypePtr getReturnType() const override
|
||||
{
|
||||
DataTypes types
|
||||
{
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
std::make_shared<DataTypeNumber<Float64>>(),
|
||||
};
|
||||
|
||||
Strings names
|
||||
{
|
||||
"t-statistic",
|
||||
"p-value"
|
||||
};
|
||||
|
||||
return std::make_shared<DataTypeTuple>(
|
||||
std::move(types),
|
||||
std::move(names)
|
||||
);
|
||||
}
|
||||
|
||||
void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena *) const override
|
||||
{
|
||||
auto col_x = assert_cast<const ColumnVector<X> *>(columns[0]);
|
||||
auto col_y = assert_cast<const ColumnVector<Y> *>(columns[1]);
|
||||
|
||||
X x = col_x->getData()[row_num];
|
||||
Y y = col_y->getData()[row_num];
|
||||
|
||||
this->data(place).add(x, y);
|
||||
}
|
||||
|
||||
void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena *) const override
|
||||
{
|
||||
this->data(place).merge(this->data(rhs));
|
||||
}
|
||||
|
||||
void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
|
||||
{
|
||||
this->data(place).serialize(buf);
|
||||
}
|
||||
|
||||
void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
|
||||
{
|
||||
this->data(place).deserialize(buf);
|
||||
}
|
||||
|
||||
void insertResultInto(AggregateDataPtr place, IColumn & to, Arena * /*arena*/) const override
|
||||
{
|
||||
size_t size_x = this->data(place).getSizeX();
|
||||
size_t size_y = this->data(place).getSizeY();
|
||||
|
||||
if (size_x < 2 || size_y < 2)
|
||||
{
|
||||
throw Exception("Aggregate function " + getName() + " requires samples to be of size > 1", ErrorCodes::BAD_ARGUMENTS);
|
||||
}
|
||||
|
||||
Float64 t_statistic = 0.0;
|
||||
Float64 p_value = 0.0;
|
||||
std::tie(t_statistic, p_value) = this->data(place).getResult();
|
||||
|
||||
/// Because p-value is a probability.
|
||||
p_value = std::min(1.0, std::max(0.0, p_value));
|
||||
|
||||
auto & column_tuple = assert_cast<ColumnTuple &>(to);
|
||||
auto & column_stat = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(0));
|
||||
auto & column_value = assert_cast<ColumnVector<Float64> &>(column_tuple.getColumn(1));
|
||||
|
||||
column_stat.getData().push_back(t_statistic);
|
||||
column_value.getData().push_back(p_value);
|
||||
}
|
||||
|
||||
};
|
||||
|
||||
};
|
Loading…
Reference in New Issue
Block a user