ClickHouse/src/Functions/evalMLMethod.cpp
2023-08-09 02:19:02 +02:00

101 lines
2.8 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypeAggregateFunction.h>
#include <Columns/ColumnAggregateFunction.h>
#include <Common/typeid_cast.h>
#include <Common/PODArray.h>
namespace DB
{
namespace ErrorCodes
{
extern const int BAD_ARGUMENTS;
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
/** finalizeAggregation(agg_state) - get the result from the aggregation state.
* Takes state of aggregate function. Returns result of aggregation (finalized state).
*/
class FunctionEvalMLMethod : public IFunction
{
public:
static constexpr auto name = "evalMLMethod";
static FunctionPtr create(ContextPtr context)
{
return std::make_shared<FunctionEvalMLMethod>(context);
}
explicit FunctionEvalMLMethod(ContextPtr context_) : context(context_)
{}
String getName() const override
{
return name;
}
bool isVariadic() const override
{
return true;
}
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override
{
return true;
}
size_t getNumberOfArguments() const override
{
return 0;
}
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
if (arguments.empty())
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Function {} requires at least one argument", getName());
const auto * type = checkAndGetDataType<DataTypeAggregateFunction>(arguments[0].get());
if (!type)
throw Exception(ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT,
"Argument for function {} must have type AggregateFunction - state "
"of aggregate function.", getName());
return type->getReturnTypeToPredict();
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
{
if (arguments.empty())
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Function {} requires at least one argument", getName());
const auto * model = arguments[0].column.get();
if (const auto * column_with_states = typeid_cast<const ColumnConst *>(model))
model = column_with_states->getDataColumnPtr().get();
const auto * agg_function = typeid_cast<const ColumnAggregateFunction *>(model);
if (!agg_function)
throw Exception(ErrorCodes::ILLEGAL_COLUMN, "Illegal column {} of first argument of function {}",
arguments[0].column->getName(), getName());
return agg_function->predictValues(arguments, context);
}
ContextPtr context;
};
}
REGISTER_FUNCTION(EvalMLMethod)
{
factory.registerFunction<FunctionEvalMLMethod>();
}
}