text: /* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
  
  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
  
  http://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. */
  
  #include <string>
  #include <vector>
  #include "paddle/fluid/framework/data_feed_factory.h"
  #include "paddle/fluid/framework/device_worker_factory.h"
  #include "paddle/fluid/framework/trainer.h"
  
  namespace paddle {
  namespace framework {
  
  void MultiTrainer::Initialize(const TrainerDesc& trainer_desc,
                                Dataset* dataset) {
    thread_num_ = trainer_desc.thread_num();
    for (int i = 0; i < trainer_desc.downpour_param().stat_var_names_size();
         i++) {
      need_merge_var_names_.push_back(
          trainer_desc.downpour_param().stat_var_names(i));
    }
    SetDataset(dataset);
    // get filelist from trainer_desc here
    const std::vector<paddle::framework::DataFeed*> readers =
        dataset->GetReaders();
    VLOG(3) << "readers num: " << readers.size();
    // change thread num to readers num
    thread_num_ = readers.size();
    VLOG(3) << "worker thread num: " << thread_num_;
    workers_.resize(thread_num_);
    for (int i = 0; i < thread_num_; ++i) {
      workers_[i] = DeviceWorkerFactory::CreateDeviceWorker(
          trainer_desc.device_worker_name());
      workers_[i]->Initialize(trainer_desc);
      workers_[i]->SetDeviceIndex(i);
      workers_[i]->SetDataFeed(readers[i]);
    }
  
    // set debug here
    SetDebug(trainer_desc.debug());
  }
  
  // call only after all resources are set in current trainer
  void MultiTrainer::InitTrainerEnv(const ProgramDesc& main_program,
                                    const platform::Place& place) {
    for (int i = 0; i < thread_num_; ++i) {
      workers_[i]->SetPlace(place);
      workers_[i]->SetReaderPlace(place);
      workers_[i]->SetRootScope(root_scope_);
      workers_[i]->CreateDeviceResource(main_program);  // Program
      workers_[i]->BindingDataFeedMemory();
    }
  }
  
  void MultiTrainer::Run() {
    VLOG(3) << "Going to run";
    for (int thidx = 0; thidx < thread_num_; ++thidx) {
      if (!debug_) {
        threads_.push_back(
            std::thread(&DeviceWorker::TrainFiles, workers_[thidx].get()));
      } else {
        threads_.push_back(std::thread(&DeviceWorker::TrainFilesWithProfiler,
                                       workers_[thidx].get()));
      }
    }
  }
  
  void MultiTrainer::Finalize() {
    for (auto& th : threads_) {
      th.join();
    }
    root_scope_->DropKids();
  }
  
  }  // end namespace framework
  }  // end namespace paddle
  