109 lines
4.2 KiB
C++
109 lines
4.2 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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#include <random>
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#include "udf/udf.h"
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#include "vec/data_types/data_type_number.h"
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#include "vec/functions/simple_function_factory.h"
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namespace doris::vectorized {
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class Random : public IFunction {
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public:
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static constexpr auto name = "random";
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static FunctionPtr create() { return std::make_shared<Random>(); }
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String get_name() const override { return name; }
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bool use_default_implementation_for_constants() const override { return false; }
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size_t get_number_of_arguments() const override { return 0; }
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bool is_variadic() const override { return true; }
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DataTypePtr get_return_type_impl(const DataTypes& arguments) const override {
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return std::make_shared<DataTypeFloat64>();
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}
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Status prepare(FunctionContext* context, FunctionContext::FunctionStateScope scope) override {
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std::mt19937_64* generator =
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reinterpret_cast<std::mt19937_64*>(context->allocate(sizeof(std::mt19937_64)));
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if (UNLIKELY(generator == nullptr)) {
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return Status::MemoryAllocFailed("allocate random seed generator failed.");
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}
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context->set_function_state(scope, generator);
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new (generator) std::mt19937_64();
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if (scope == FunctionContext::THREAD_LOCAL) {
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if (context->get_num_args() == 1) {
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// This is a call to RandSeed, initialize the seed
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// TODO: should we support non-constant seed?
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if (!context->is_col_constant(0)) {
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return Status::InvalidArgument("Seed argument to rand() must be constant.");
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}
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uint32_t seed = 0;
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if (!context->get_constant_col(0)->column_ptr->is_null_at(0)) {
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seed = context->get_constant_col(0)->column_ptr->get64(0);
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}
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generator->seed(seed);
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} else {
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generator->seed(std::random_device()());
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}
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}
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return Status::OK();
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}
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Status execute_impl(FunctionContext* context, Block& block, const ColumnNumbers& arguments,
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size_t result, size_t input_rows_count) override {
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static const double min = 0.0;
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static const double max = 1.0;
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auto res_column = ColumnFloat64::create(input_rows_count);
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auto& res_data = assert_cast<ColumnFloat64&>(*res_column).get_data();
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std::mt19937_64* generator = reinterpret_cast<std::mt19937_64*>(
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context->get_function_state(FunctionContext::THREAD_LOCAL));
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DCHECK(generator != nullptr);
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std::uniform_real_distribution<double> distribution(min, max);
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for (int i = 0; i < input_rows_count; i++) {
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res_data[i] = distribution(*generator);
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}
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block.replace_by_position(result, std::move(res_column));
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return Status::OK();
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}
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Status close(FunctionContext* context, FunctionContext::FunctionStateScope scope) override {
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if (scope == FunctionContext::THREAD_LOCAL) {
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uint8_t* generator = reinterpret_cast<uint8_t*>(
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context->get_function_state(FunctionContext::THREAD_LOCAL));
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context->free(generator);
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context->set_function_state(FunctionContext::THREAD_LOCAL, nullptr);
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}
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return Status::OK();
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}
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};
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void register_function_random(SimpleFunctionFactory& factory) {
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factory.register_function<Random>();
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factory.register_alias(Random::name, "rand");
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}
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} // namespace doris::vectorized
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