code: #
  # A wrapper script that trains the SELDnet. The training stops when the early stopping metric - SELD error stops improving.
  #
  
  import os
  import sys
  import numpy as np
  import cls_feature_class
  import cls_data_generator
  from cls_compute_seld_results import ComputeSELDResults, reshape_3Dto2D
  import keras_model
  import parameter
  import time
  
  def dump_DCASE2021_results(_data_gen, _feat_cls, _dcase_output_folder, _sed_pred, _doa_pred):
      '''
      Write the filewise results to individual csv files
      '''
  
      # Number of frames for a 60 second audio with 100ms hop length = 600 frames
      max_frames_with_content = _data_gen.get_nb_frames()
  
      # Number of frames in one batch (batch_size* sequence_length) consists of all the 600 frames above with
      # zero padding in the remaining frames
      test_filelist = _data_gen.get_filelist()
      frames_per_file = _data_gen.get_frame_per_file()
      for file_cnt in range(_sed_pred.shape[0] // frames_per_file):
          output_file = os.path.join(_dcase_output_folder, test_filelist[file_cnt].replace('.npy', '.csv'))
          dc = file_cnt * frames_per_file
          output_dict = _feat_cls.regression_label_format_to_output_format(
              _sed_pred[dc:dc + max_frames_with_content, :],
              _doa_pred[dc:dc + max_frames_with_content, :]
          )
          _data_gen.write_output_format_file(output_file, output_dict)
      return
  
  
  def get_accdoa_labels(accdoa_in, nb_classes):
      x, y, z = accdoa_in[:, :, :nb_classes], accdoa_in[:, :, nb_classes:2*nb_classes], accdoa_in[:, :, 2*nb_classes:]
      sed = np.sqrt(x**2 + y**2 + z**2) > 0.5
        
      return sed, accdoa_in
  
  def main(argv):
      """
      Main wrapper for training sound event localization and detection network.
      
      :param argv: expects two optional inputs. 
          first input: task_id - (optional) To chose the system configuration in parameters.py.
                                  (default) 1 - uses default parameters
          second input: job_id - (optional) all the output files will be uniquely represented with this.
                                (default) 1
  
      """
      print(argv)
      if len(argv) != 3:
          print('\n\n')
          print('-------------------------------------------------------------------------------------------------------')
          print('The code expected two optional inputs')
          print('\t>> python seld.py <task-id> <job-id>')
          print('\t\t<task-id> is used to choose the user-defined parameter set from parameter.py')
          print('Using default inputs for now')
          print('\t\t<job-id> is a unique identifier which is used for output filenames (models, training plots). '
                'You can use any number or string for this.')
          print('-------------------------------------------------------------------------------------------------------')
          print('\n\n')
  
      # use parameter set defined by user
      task_id = '1' if len(argv) < 2 else argv[1]
      params = parameter.get_params(task_id)
  
      job_id = 1 if len(argv) < 3 else argv[-1]
  
      feat_cls = cls_feature_class.FeatureClass(params)
      train_splits, val_splits, test_splits = None, None, None
  
      if params['mode'] == 'dev':
          test_splits = [6]
          val_splits = [5]
          train_splits = [[1, 2, 3, 4]]
  
      elif params['mode'] == 'eval':
          test_splits = [[7, 8]]
          val_splits = [[6]]
          train_splits = [[1, 2, 3, 4, 5]]
  
      for split_cnt, split in enumerate(test_splits):
          print('\n\n---------------------------------------------------------------------------------------------------')
          print('------------------------------------      SPLIT {}   -----------------------------------------------'.format(split))
          print('---------------------------------------------------------------------------------------------------')
  
          # Unique name for the run
          cls_feature_class.create_folder(params['model_dir'])
          unique_name = '{}_{}_{}_{}_split{}'.format(
              task_id, job_id, params['dataset'], params['mode'], split
          )
          unique_name = os.path.join(params['model_dir'], unique_name)
          model_name = '{}_model.h5'.format(unique_name)
          print("unique_name: {}\n".format(unique_name))
  
          # Load train and validation data
          print('Loading training dataset:')
          data_gen_train = cls_data_generator.DataGenerator(
              params=params, split=train_splits[split_cnt]
          )
  
          print('Loading validation dataset:')
          data_gen_val = cls_data_generator.DataGenerator(
              params=params, split=val_splits[split_cnt], shuffle=False, per_file=True, is_eval=False
          )
  
          # Collect the reference labels for validation data
          data_in, data_out = data_gen_train.get_data_sizes()
          print('FEATURES:\n\tdata_in: {}\n\tdata_out: {}\n'.format(data_in, data_out))
  
          nb_classes = data_gen_train.get_nb_classes()
          print('MODEL:\n\tdropout_rate: {}\n\tCNN: nb_cnn_filt: {}, f_pool_size{}, t_pool_size{}\n\trnn_size: {}, fnn_size: {}\n\tdoa_objective: {}\n'.format(
              params['dropout_rate'], params['nb_cnn2d_filt'], params['f_pool_size'], params['t_pool_size'], params['rnn_size'],
              params['fnn_size'], params['doa_objective']))
  
          print('Using loss weights : {}'.format(params['loss_weights']))
          model = keras_model.get_model(data_in=data_in, data_out=data_out, dropout_rate=params['dropout_rate'],
                                        nb_cnn2d_filt=params['nb_cnn2d_filt'], f_pool_size=params['f_pool_size'], t_pool_size=params['t_pool_size'],
                                        rnn_size=params['rnn_size'], fnn_size=params['fnn_size'],
                                        weights=params['loss_weights'], doa_objective=params['doa_objective'], is_accdoa=params['is_accdoa'])
  
          # Dump results in DCASE output format for calculating final scores
          dcase_output_val_folder = os.path.join(params['dcase_output_dir'], '{}_{}_{}_val'.format(task_id, params['dataset'], params['mode']))
          cls_feature_class.delete_and_create_folder(dcase_output_val_folder)
          print('Dumping recording-wise val results in: {}'.format(dcase_output_val_folder))
  
          # Initialize evaluation metric class
          score_obj = ComputeSELDResults(params)
  
          best_seld_metric = 99999
          best_epoch = -1
          patience_cnt = 0
          nb_epoch = 2 if params['quick_test'] else params['nb_epochs']
          tr_loss = np.zeros(nb_epoch)
          seld_metric = np.zeros((nb_epoch, 5))
  
          # start training
          for epoch_cnt in range(nb_epoch):
              start = time.time()
  
              # train once per epoch
              hist = model.fit_generator(
                  generator=data_gen_train.generate(),
                  steps_per_epoch=2 if params['quick_test'] else data_gen_train.get_total_batches_in_data(),
                  epochs=params['epochs_per_fit'],
                  verbose=2,
              )
              tr_loss[epoch_cnt] = hist.history.get('loss')[-1]
  
              # predict once per epoch
              pred = model.predict_generator(
                  generator=data_gen_val.generate(),
                  steps=2 if params['quick_test'] else data_gen_val.get_total_batches_in_data(),
                  verbose=2
              )
  
              if params['is_accdoa']:
                  sed_pred, doa_pred = get_accdoa_labels(pred, nb_classes)
                  sed_pred = reshape_3Dto2D(sed_pred)
                  doa_pred = reshape_3Dto2D(doa_pred)
              else:
                  sed_pred = reshape_3Dto2D(pred[0]) > 0.5
                  doa_pred = reshape_3Dto2D(pred[1] if params['doa_objective'] is 'mse' else pred[1][:, :, nb_classes:])
              
              # Calculate the DCASE 2021 metrics - Location-aware detection and Class-aware localization scores
              dump_DCASE2021_results(data_gen_val, feat_cls, dcase_output_val_folder, sed_pred, doa_pred)
              seld_metric[epoch_cnt, :] = score_obj.get_SELD_Results(dcase_output_val_folder)
  
              patience_cnt += 1
              if seld_metric[epoch_cnt, -1] < best_seld_metric:
                  best_seld_metric = seld_metric[epoch_cnt, -1]
                  best_epoch = epoch_cnt
                  model.save(model_name)
                  patience_cnt = 0
  
              print(
                  'epoch_cnt: {}, time: {:0.2f}s, tr_loss: {:0.2f}, '
                  '\n\t\t DCASE2021 SCORES: ER: {:0.2f}, F: {:0.1f}, LE: {:0.1f}, LR:{:0.1f}, seld_score (early stopping score): {:0.2f}, '
                  'best_seld_score: {:0.2f}, best_epoch : {}\n'.format(
                      epoch_cnt, time.time() - start, tr_loss[epoch_cnt],
                      seld_metric[epoch_cnt, 0], seld_metric[epoch_cnt, 1]*100,
                      seld_metric[epoch_cnt, 2], seld_metric[epoch_cnt, 3]*100,
                      seld_metric[epoch_cnt, -1], best_seld_metric, best_epoch
                  )
              )
              if patience_cnt > params['patience']:
                  break
  
          print('\nResults on validation split:')
          print('\tUnique_name: {} '.format(unique_name))
          print('\tSaved model for the best_epoch: {}'.format(best_epoch))
          print('\tSELD_score (early stopping score) : {}'.format(best_seld_metric))
  
          print('\n\tDCASE2021 scores')
          print('\tClass-aware localization scores: Localization Error: {:0.1f}, Localization Recall: {:0.1f}'.format(seld_metric[best_epoch, 2], seld_metric[best_epoch, 3]*100))
          print('\tLocation-aware detection scores: Error rate: {:0.2f}, F-score: {:0.1f}'.format(seld_metric[best_epoch, 0], seld_metric[best_epoch, 1]*100))
  
          # ------------------  Calculate metric scores for unseen test split ---------------------------------
          print('\nLoading the best model and predicting results on the testing split')
          print('\tLoading testing dataset:')
          data_gen_test = cls_data_generator.DataGenerator(
              params=params, split=split, shuffle=False, per_file=True, is_eval=True if params['mode'] is 'eval' else False
          )
  
          model = keras_model.load_seld_model('{}_model.h5'.format(unique_name), params['doa_objective'])
          pred_test = model.predict_generator(
              generator=data_gen_test.generate(),
              steps=2 if params['quick_test'] else data_gen_test.get_total_batches_in_data(),
              verbose=2
          )
          if params['is_accdoa']:
              test_sed_pred, test_doa_pred = get_accdoa_labels(pred_test, nb_classes)
              test_sed_pred = reshape_3Dto2D(test_sed_pred)
              test_doa_pred = reshape_3Dto2D(test_doa_pred)
          else:
              test_sed_pred = reshape_3Dto2D(pred_test[0]) > 0.5
              test_doa_pred = reshape_3Dto2D(pred_test[1] if params['doa_objective'] is 'mse' else pred_test[1][:, :, nb_classes:])
  
  
  
          # Dump results in DCASE output format for calculating final scores
          dcase_output_test_folder = os.path.join(params['dcase_output_dir'], '{}_{}_{}_test'.format(task_id, params['dataset'], params['mode']))
          cls_feature_class.delete_and_create_folder(dcase_output_test_folder)
          print('Dumping recording-wise test results in: {}'.format(dcase_output_test_folder))
          dump_DCASE2021_results(data_gen_test, feat_cls, dcase_output_test_folder, test_sed_pred, test_doa_pred)
  
          if params['mode'] is 'dev':
              # Calculate DCASE2021 scores
              test_seld_metric = score_obj.get_SELD_Results(dcase_output_test_folder)
  
              print('Results on test split:')
              print('\tDCASE2021 Scores')
              print('\tClass-aware localization scores: Localization Error: {:0.1f}, Localization Recall: {:0.1f}'.format(test_seld_metric[2], test_seld_metric[3]*100))
              print('\tLocation-aware detection scores: Error rate: {:0.2f}, F-score: {:0.1f}'.format(test_seld_metric[0], test_seld_metric[1]*100))
              print('\tSELD (early stopping metric): {:0.2f}'.format(test_seld_metric[-1]))
  
  
  if __name__ == "__main__":
      try:
          sys.exit(main(sys.argv))
      except (ValueError, IOError) as e:
          sys.exit(e)
  
apis: numpy.sqrt numpy.zeros