ClickHouse

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#include <AggregateFunctions/AggregateFunctionFactory.h>
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#include <AggregateFunctions/CrossTab.h>
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#include <AggregateFunctions/FactoryHelpers.h>
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#include <memory>
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#include <cmath>
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namespace DB
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{
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namespace
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{
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struct CramersVData : CrossTabData
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{
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    static const char * getName()
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    {
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        return "cramersV";
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    }
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    Float64 getResult() const
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    {
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        if (count < 2)
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            return std::numeric_limits<Float64>::quiet_NaN();
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        UInt64 q = std::min(count_a.size(), count_b.size());
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        return sqrt(getPhiSquared() / (q - 1));
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    }
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};
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}
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void registerAggregateFunctionCramersV(AggregateFunctionFactory & factory)
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{
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    factory.registerFunction(CramersVData::getName(),
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        [](const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
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        {
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            assertBinary(name, argument_types);
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            assertNoParameters(name, parameters);
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            return std::make_shared<AggregateFunctionCrossTab<CramersVData>>(argument_types);
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        });
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}
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}
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