joint_distribution_sample_generator.h

// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef DISTBENCH_JOINT_DISTRIBUTION_SAMPLE_GENERATOR_H_
#define DISTBENCH_JOINT_DISTRIBUTION_SAMPLE_GENERATOR_H_

#include <functional>

#include "absl/random/bit_gen_ref.h"
#include "absl/random/random.h"
#include "absl/status/statusor.h"
#include "joint_distribution.pb.h"

namespace distbench {

class DistributionSampleGenerator {
 public:
  ~DistributionSampleGenerator() {}

  absl::Status Initialize(const DistributionConfig& config);
  std::vector<int64_t> GetRandomSample(absl::BitGenRef generator);
  int64_t GetScalarRandomSample(absl::BitGenRef generator);

 private:
  int num_dimensions_;

  std::discrete_distribution<int64_t> distribution_array_;

  std::vector<std::vector<int64_t>> exact_value_;

  std::vector<std::vector<std::uniform_int_distribution<>>> range_;

  std::vector<std::vector<bool>> is_exact_value_;

  absl::Status InitializeWithPmf(const DistributionConfig& config);
  absl::Status InitializeWithCdf(const DistributionConfig& config);
};

absl::StatusOr<std::unique_ptr<DistributionSampleGenerator>>
AllocateSampleGenerator(const DistributionConfig& config);

}  // namespace distbench

#endif  // DISTBENCH_JOINT_DISTRIBUTION_SAMPLE_GENERATOR_H_