ClickHouse/src/Functions/abtesting.cpp
2020-08-08 03:47:03 +03:00

322 lines
10 KiB
C++

#include <Functions/abtesting.h>
#if !defined(ARCADIA_BUILD) && USE_STATS
#include <math.h>
#include <sstream>
#include <DataTypes/DataTypeString.h>
#include <Columns/ColumnString.h>
#include <Columns/ColumnConst.h>
#include <Columns/ColumnsNumber.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <IO/WriteHelpers.h>
#include <IO/WriteBufferFromOStream.h>
#define STATS_ENABLE_STDVEC_WRAPPERS
#include <stats.hpp>
namespace DB
{
namespace ErrorCodes
{
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
extern const int BAD_ARGUMENTS;
}
static const String BETA = "beta";
static const String GAMMA = "gamma";
template <bool higher_is_better>
Variants bayesian_ab_test(String distribution, PODArray<Float64> & xs, PODArray<Float64> & ys)
{
const size_t r = 1000, c = 100;
Variants variants(xs.size(), {0.0, 0.0, 0.0, 0.0});
std::vector<std::vector<Float64>> samples_matrix;
for (size_t i = 0; i < xs.size(); ++i)
{
variants[i].x = xs[i];
variants[i].y = ys[i];
}
if (distribution == BETA)
{
Float64 alpha, beta;
for (size_t i = 0; i < xs.size(); ++i)
if (xs[i] < ys[i])
throw Exception("Conversions cannot be larger than trials", ErrorCodes::BAD_ARGUMENTS);
for (size_t i = 0; i < xs.size(); ++i)
{
alpha = 1.0 + ys[i];
beta = 1.0 + xs[i] - ys[i];
samples_matrix.emplace_back(stats::rbeta<std::vector<Float64>>(r, c, alpha, beta));
}
}
else if (distribution == GAMMA)
{
Float64 shape, scale;
for (size_t i = 0; i < xs.size(); ++i)
{
shape = 1.0 + xs[i];
scale = 250.0 / (1 + 250.0 * ys[i]);
std::vector<Float64> samples = stats::rgamma<std::vector<Float64>>(r, c, shape, scale);
for (auto & sample : samples)
sample = 1 / sample;
samples_matrix.emplace_back(std::move(samples));
}
}
PODArray<Float64> means;
for (auto & samples : samples_matrix)
{
Float64 total = 0.0;
for (auto sample : samples)
total += sample;
means.push_back(total / samples.size());
}
// Beats control
for (size_t i = 1; i < xs.size(); ++i)
{
for (size_t n = 0; n < r * c; ++n)
{
if (higher_is_better)
{
if (samples_matrix[i][n] > samples_matrix[0][n])
++variants[i].beats_control;
}
else
{
if (samples_matrix[i][n] < samples_matrix[0][n])
++variants[i].beats_control;
}
}
}
for (auto & variant : variants)
variant.beats_control = static_cast<Float64>(variant.beats_control) / r / c;
// To be best
PODArray<size_t> count_m(xs.size(), 0);
PODArray<Float64> row(xs.size(), 0);
for (size_t n = 0; n < r * c; ++n)
{
for (size_t i = 0; i < xs.size(); ++i)
row[i] = samples_matrix[i][n];
Float64 m;
if (higher_is_better)
m = *std::max_element(row.begin(), row.end());
else
m = *std::min_element(row.begin(), row.end());
for (size_t i = 0; i < xs.size(); ++i)
{
if (m == samples_matrix[i][n])
{
++variants[i].best;
break;
}
}
}
for (auto & variant : variants)
variant.best = static_cast<Float64>(variant.best) / r / c;
return variants;
}
String convertToJson(const PODArray<String> & variant_names, const Variants & variants)
{
FormatSettings settings;
std::stringstream s;
{
WriteBufferFromOStream buf(s);
writeCString("{\"data\":[", buf);
for (size_t i = 0; i < variants.size(); ++i)
{
writeCString("{\"variant_name\":", buf);
writeJSONString(variant_names[i], buf, settings);
writeCString(",\"x\":", buf);
writeText(variants[i].x, buf);
writeCString(",\"y\":", buf);
writeText(variants[i].y, buf);
writeCString(",\"beats_control\":", buf);
writeText(variants[i].beats_control, buf);
writeCString(",\"to_be_best\":", buf);
writeText(variants[i].best, buf);
writeCString("}", buf);
if (i != variant_names.size() -1) writeCString(",", buf);
}
writeCString("]}", buf);
}
return s.str();
}
class FunctionBayesAB : public IFunction
{
public:
static constexpr auto name = "bayesAB";
static FunctionPtr create(const Context &)
{
return std::make_shared<FunctionBayesAB>();
}
String getName() const override
{
return name;
}
bool isDeterministic() const override { return false; }
bool isDeterministicInScopeOfQuery() const override { return false; }
size_t getNumberOfArguments() const override { return 5; }
DataTypePtr getReturnTypeImpl(const DataTypes &) const override
{
return std::make_shared<DataTypeString>();
}
static bool toFloat64(const ColumnConst * col_const_arr, PODArray<Float64> & output)
{
Array src_arr = col_const_arr->getValue<Array>();
for (size_t i = 0, size = src_arr.size(); i < size; ++i)
{
switch (src_arr[i].getType())
{
case Field::Types::Int64:
output.push_back(static_cast<Float64>(src_arr[i].get<const Int64 &>()));
break;
case Field::Types::UInt64:
output.push_back(static_cast<Float64>(src_arr[i].get<const UInt64 &>()));
break;
case Field::Types::Float64:
output.push_back(src_arr[i].get<const Float64 &>());
break;
default:
return false;
}
}
return true;
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t input_rows_count) const override
{
if (input_rows_count == 0)
{
block.getByPosition(result).column = ColumnString::create();
return;
}
PODArray<Float64> xs, ys;
PODArray<String> variant_names;
String dist;
bool higher_is_better;
if (const ColumnConst * col_dist = checkAndGetColumnConst<ColumnString>(block.getByPosition(arguments[0]).column.get()))
{
dist = col_dist->getDataAt(0).data;
dist = Poco::toLower(dist);
if (dist != BETA && dist != GAMMA)
throw Exception("First argument for function " + getName() + " cannot be " + dist, ErrorCodes::BAD_ARGUMENTS);
}
else
throw Exception("First argument for function " + getName() + " must be Constant string", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (const ColumnConst * col_higher_is_better = checkAndGetColumnConst<ColumnUInt8>(block.getByPosition(arguments[1]).column.get()))
higher_is_better = col_higher_is_better->getBool(0);
else
throw Exception("Second argument for function " + getName() + " must be Constatnt boolean", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (const ColumnConst * col_const_arr = checkAndGetColumnConst<ColumnArray>(block.getByPosition(arguments[2]).column.get()))
{
if (!col_const_arr)
throw Exception("Third argument for function " + getName() + " must be Array of constant strings", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
Array src_arr = col_const_arr->getValue<Array>();
for (size_t i = 0; i < src_arr.size(); ++i)
{
if (src_arr[i].getType() != Field::Types::String)
throw Exception("Third argument for function " + getName() + " must be Array of constant strings", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
variant_names.push_back(src_arr[i].get<const String &>());
}
}
if (const ColumnConst * col_const_arr = checkAndGetColumnConst<ColumnArray>(block.getByPosition(arguments[3]).column.get()))
{
if (!col_const_arr)
throw Exception("Forth argument for function " + getName() + " must be Array of constant numbers", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (!toFloat64(col_const_arr, xs))
throw Exception("Forth and fifth Argument for function " + getName() + " must be Array of constant Numbers", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
if (const ColumnConst * col_const_arr = checkAndGetColumnConst<ColumnArray>(block.getByPosition(arguments[4]).column.get()))
{
if (!col_const_arr)
throw Exception("Fifth argument for function " + getName() + " must be Array of constant numbers", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
if (!toFloat64(col_const_arr, ys))
throw Exception("Fifth Argument for function " + getName() + " must be Array of constant Numbers", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
}
if (variant_names.size() != xs.size() || xs.size() != ys.size())
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Sizes of arguments doesn't match: variant_names: {}, xs: {}, ys: {}", variant_names.size(), xs.size(), ys.size());
if (variant_names.size() < 2)
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Sizes of arguments must be larger than 1. variant_names: {}, xs: {}, ys: {}", variant_names.size(), xs.size(), ys.size());
if (std::count_if(xs.begin(), xs.end(), [](Float64 v) { return v < 0; }) > 0 ||
std::count_if(ys.begin(), ys.end(), [](Float64 v) { return v < 0; }) > 0)
throw Exception("Negative values don't allowed", ErrorCodes::BAD_ARGUMENTS);
Variants variants;
if (higher_is_better)
variants = bayesian_ab_test<true>(dist, xs, ys);
else
variants = bayesian_ab_test<false>(dist, xs, ys);
auto dst = ColumnString::create();
std::string result_str = convertToJson(variant_names, variants);
dst->insertData(result_str.c_str(), result_str.length());
block.getByPosition(result).column = std::move(dst);
}
};
void registerFunctionBayesAB(FunctionFactory & factory)
{
factory.registerFunction<FunctionBayesAB>();
}
}
#else
namespace DB
{
class FunctionFactory;
void registerFunctionBayesAB(FunctionFactory & /* factory */)
{
}
}
#endif