Example #1
0
    def initialize_model(self,
                         train_set_metadata=None,
                         train_set_metadata_json=None,
                         gpus=None,
                         gpu_fraction=1,
                         random_seed=default_random_seed,
                         debug=False,
                         **kwargs):
        """This function initializes a model. It is need for performing online
        learning, so it has to be called before `train_online`.
        `train` initialize the model under the hood, so there is no need to call
        this function if you don't use `train_online`.

        # Inputs

        :param train_set_metadata: (dict) it contains metadata information for
               the input and output features the model is going to be trained
               on. It's the same content of the metadata json file that is
               created while training.
        :param train_set_metadata_json: (string)  path to the JSON metadata file
               created while training. it contains metadata information for the
               input and output features the model is going to be trained on
        :param gpus: (string, default: `None`) list of GPUs to use (it uses the
               same syntax of CUDA_VISIBLE_DEVICES)
        :param gpu_fraction: (float, default `1.0`) fraction of GPU memory to
               initialize the process with
        :param random_seed: (int, default`42`) a random seed that is going to be
               used anywhere there is a call to a random number generator: data
               splitting, parameter initialization and training set shuffling
        :param debug: (bool, default: `False`) enables debugging mode
        """

        if train_set_metadata is None and train_set_metadata_json is None:
            raise ValueError(
                'train_set_metadata or train_set_metadata_json must not None.')
        if train_set_metadata_json is not None:
            train_set_metadata = load_metadata(train_set_metadata_json)

        # update model definition with metadata properties
        update_model_definition_with_metadata(self.model_definition,
                                              train_set_metadata)

        # build model
        model = Model(self.model_definition['input_features'],
                      self.model_definition['output_features'],
                      self.model_definition['combiner'],
                      self.model_definition['training'],
                      self.model_definition['preprocessing'],
                      random_seed=random_seed,
                      debug=debug)
        model.initialize_session(gpus=gpus, gpu_fraction=gpu_fraction)

        # set parameters
        self.model = model
        self.train_set_metadata = train_set_metadata
Example #2
0
def experiment(model_definition,
               model_definition_file=None,
               data_csv=None,
               data_train_csv=None,
               data_validation_csv=None,
               data_test_csv=None,
               data_hdf5=None,
               data_train_hdf5=None,
               data_validation_hdf5=None,
               data_test_hdf5=None,
               train_set_metadata_json=None,
               experiment_name='experiment',
               model_name='run',
               model_load_path=None,
               model_resume_path=None,
               skip_save_model=False,
               skip_save_progress=False,
               skip_save_log=False,
               skip_save_processed_input=False,
               skip_save_unprocessed_output=False,
               output_directory='results',
               gpus=None,
               gpu_fraction=1.0,
               use_horovod=False,
               random_seed=default_random_seed,
               debug=False,
               **kwargs):
    """Trains a model on a dataset's training and validation splits and
    uses it to predict on the test split.
    It saves the trained model and the statistics of training and testing.
    :param model_definition: Model definition which defines the different
           parameters of the model, features, preprocessing and training.
    :type model_definition: Dictionary
    :param model_definition_file: The file that specifies the model definition.
           It is a yaml file.
    :type model_definition_file: filepath (str)
    :param data_csv: A CSV file contanining the input data which is used to
           train, validate and test a model. The CSV either contains a
           split column or will be split.
    :type data_csv: filepath (str)
    :param data_train_csv: A CSV file contanining the input data which is used
           to train a model.
    :type data_train_csv: filepath (str)
    :param data_validation_csv: A CSV file contanining the input data which is used
           to validate a model..
    :type data_validation_csv: filepath (str)
    :param data_test_csv: A CSV file contanining the input data which is used
           to test a model.
    :type data_test_csv: filepath (str)
    :param data_hdf5: If the dataset is in the hdf5 format, this is used instead
           of the csv file.
    :type data_hdf5: filepath (str)
    :param data_train_hdf5: If the training set is in the hdf5 format, this is
           used instead of the csv file.
    :type data_train_hdf5: filepath (str)
    :param data_validation_hdf5: If the validation set is in the hdf5 format,
           this is used instead of the csv file.
    :type data_validation_hdf5: filepath (str)
    :param data_test_hdf5: If the test set is in the hdf5 format, this is
           used instead of the csv file.
    :type data_test_hdf5: filepath (str)
    :param train_set_metadata_json: If the dataset is in hdf5 format, this is
           the associated json file containing metadata.
    :type train_set_metadata_json: filepath (str)
    :param experiment_name: The name for the experiment.
    :type experiment_name: Str
    :param model_name: Name of the model that is being used.
    :type model_name: Str
    :param model_load_path: If this is specified the loaded model will be used
           as initialization (useful for transfer learning).
    :type model_load_path: filepath (str)
    :param model_resume_path: Resumes training of the model from the path
           specified. The difference with model_load_path is that also training
           statistics like the current epoch and the loss and performance so
           far are also resumed effectively cotinuing a previously interrupted
           training process.
    :type model_resume_path: filepath (str)
    :param skip_save_model: Disables
               saving model weights and hyperparameters each time the model
           improves. By default Ludwig saves model weights after each epoch
           the validation measure imrpvoes, but if the model is really big
           that can be time consuming if you do not want to keep
           the weights and just find out what performance can a model get
           with a set of hyperparameters, use this parameter to skip it,
           but the model will not be loadable later on.
    :type skip_save_model: Boolean
    :param skip_save_progress: Disables saving
           progress each epoch. By default Ludwig saves weights and stats
           after each epoch for enabling resuming of training, but if
           the model is really big that can be time consuming and will uses
           twice as much space, use this parameter to skip it, but training
           cannot be resumed later on.
    :type skip_save_progress: Boolean
    :param skip_save_log: Disables saving TensorBoard
           logs. By default Ludwig saves logs for the TensorBoard, but if it
           is not needed turning it off can slightly increase the
           overall speed..
    :type skip_save_log: Boolean
    :param skip_save_processed_input: If a CSV dataset is provided it is
           preprocessed and then saved as an hdf5 and json to avoid running
           the preprocessing again. If this parameter is False,
           the hdf5 and json file are not saved.
    :type skip_save_processed_input: Boolean
    :param skip_save_unprocessed_output: By default predictions and
           their probabilities are saved in both raw unprocessed numpy files
           contaning tensors and as postprocessed CSV files
           (one for each output feature). If this parameter is True,
           only the CSV ones are saved and the numpy ones are skipped.
    :type skip_save_unprocessed_output: Boolean
    :param output_directory: The directory that will contanin the training
           statistics, the saved model and the training procgress files.
    :type output_directory: filepath (str)
    :param gpus: List of GPUs that are available for training.
    :type gpus: List
    :param gpu_fraction: Fraction of the memory of each GPU to use at
           the beginning of the training. The memory may grow elastically.
    :type gpu_fraction: Integer
    :param random_seed: Random seed used for weights initialization,
           splits and any other random function.
    :type random_seed: Integer
    :param debug: If true turns on tfdbg with inf_or_nan checks.
    :type debug: Boolean
    """
    # set input features defaults
    if model_definition_file is not None:
        with open(model_definition_file, 'r') as def_file:
            model_definition = merge_with_defaults(yaml.load(def_file))
    else:
        model_definition = merge_with_defaults(model_definition)

    # setup directories and file names
    experiment_dir_name = None
    if model_resume_path is not None:
        if os.path.exists(model_resume_path):
            experiment_dir_name = model_resume_path
        else:
            if is_on_master():
                logging.info('Model resume path does not exists, '
                             'starting training from scratch')
            model_resume_path = None

    if model_resume_path is None:
        if is_on_master():
            experiment_dir_name = get_experiment_dir_name(
                output_directory, experiment_name, model_name)
        else:
            experiment_dir_name = '/'
    description_fn, training_stats_fn, model_dir = get_file_names(
        experiment_dir_name)

    # save description
    description = get_experiment_description(
        model_definition, data_csv, data_train_csv, data_validation_csv,
        data_test_csv, data_hdf5, data_train_hdf5, data_validation_hdf5,
        data_test_hdf5, train_set_metadata_json, random_seed)
    if is_on_master():
        save_json(description_fn, description)
        # print description
        logging.info('Experiment name: {}'.format(experiment_name))
        logging.info('Model name: {}'.format(model_name))
        logging.info('Output path: {}'.format(experiment_dir_name))
        logging.info('')
        for key, value in description.items():
            logging.info('{}: {}'.format(key, pformat(value, indent=4)))
        logging.info('')

    # preprocess
    (training_set, validation_set, test_set,
     train_set_metadata) = preprocess_for_training(
         model_definition,
         data_csv=data_csv,
         data_train_csv=data_train_csv,
         data_validation_csv=data_validation_csv,
         data_test_csv=data_test_csv,
         data_hdf5=data_hdf5,
         data_train_hdf5=data_train_hdf5,
         data_validation_hdf5=data_validation_hdf5,
         data_test_hdf5=data_test_hdf5,
         train_set_metadata_json=train_set_metadata_json,
         skip_save_processed_input=skip_save_processed_input,
         preprocessing_params=model_definition['preprocessing'],
         random_seed=random_seed)
    if is_on_master():
        logging.info('Training set: {0}'.format(training_set.size))
        if validation_set is not None:
            logging.info('Validation set: {0}'.format(validation_set.size))
        if test_set is not None:
            logging.info('Test set: {0}'.format(test_set.size))

    # update model definition with metadata properties
    update_model_definition_with_metadata(model_definition, train_set_metadata)

    # run the experiment
    model, training_results = train(training_set=training_set,
                                    validation_set=validation_set,
                                    test_set=test_set,
                                    model_definition=model_definition,
                                    save_path=model_dir,
                                    model_load_path=model_load_path,
                                    resume=model_resume_path is not None,
                                    skip_save_model=skip_save_model,
                                    skip_save_progress=skip_save_progress,
                                    skip_save_log=skip_save_log,
                                    gpus=gpus,
                                    gpu_fraction=gpu_fraction,
                                    use_horovod=use_horovod,
                                    random_seed=random_seed,
                                    debug=debug)
    (train_trainset_stats, train_valisest_stats,
     train_testset_stats) = training_results

    if is_on_master():
        if not skip_save_model:
            # save train set metadata
            save_json(os.path.join(model_dir, TRAIN_SET_METADATA_FILE_NAME),
                      train_set_metadata)

    # grab the results of the model with highest validation test performance
    validation_field = model_definition['training']['validation_field']
    validation_measure = model_definition['training']['validation_measure']
    validation_field_result = train_valisest_stats[validation_field]

    best_function = get_best_function(validation_measure)

    # print results of the model with highest validation test performance
    if is_on_master():
        if validation_set is not None:
            # max or min depending on the measure
            epoch_best_vali_measure, best_vali_measure = best_function(
                enumerate(validation_field_result[validation_measure]),
                key=lambda pair: pair[1])
            logging.info('Best validation model epoch: {0}'.format(
                epoch_best_vali_measure + 1))
            logging.info(
                'Best validation model {0} on validation set {1}: {2}'.format(
                    validation_measure, validation_field, best_vali_measure))

            if test_set is not None:
                best_vali_measure_epoch_test_measure = train_testset_stats[
                    validation_field][validation_measure][
                        epoch_best_vali_measure]
                logging.info(
                    'Best validation model {0} on test set {1}: {2}'.format(
                        validation_measure, validation_field,
                        best_vali_measure_epoch_test_measure))

    # save training statistics
    if is_on_master():
        save_json(
            training_stats_fn, {
                'train': train_trainset_stats,
                'validation': train_valisest_stats,
                'test': train_testset_stats
            })

    if test_set is not None:
        # predict
        test_results = predict(test_set,
                               train_set_metadata,
                               model,
                               model_definition,
                               model_definition['training']['batch_size'],
                               only_predictions=False,
                               gpus=gpus,
                               gpu_fraction=gpu_fraction,
                               debug=debug)
        # postprocess
        postprocessed_output = postprocess(
            test_results, model_definition['output_features'],
            train_set_metadata, experiment_dir_name,
            skip_save_unprocessed_output or not is_on_master())

        if is_on_master():
            print_prediction_results(test_results)

            save_prediction_outputs(postprocessed_output, experiment_dir_name)
            save_prediction_statistics(test_results, experiment_dir_name)

    model.close_session()

    if is_on_master():
        logging.info('\nFinished: {0}_{1}'.format(experiment_name, model_name))
        logging.info('Saved to: {}'.format(experiment_dir_name))

    return experiment_dir_name
Example #3
0
    def train(self,
              data_df=None,
              data_train_df=None,
              data_validation_df=None,
              data_test_df=None,
              data_csv=None,
              data_train_csv=None,
              data_validation_csv=None,
              data_test_csv=None,
              data_hdf5=None,
              data_train_hdf5=None,
              data_validation_hdf5=None,
              data_test_hdf5=None,
              train_set_metadata_json=None,
              dataset_type='generic',
              model_name='run',
              model_load_path=None,
              model_resume_path=None,
              skip_save_model=False,
              skip_save_progress=False,
              skip_save_log=False,
              skip_save_processed_input=False,
              output_directory='results',
              gpus=None,
              gpu_fraction=1.0,
              random_seed=42,
              logging_level=logging.ERROR,
              debug=False,
              **kwargs):
        """This function is used to perform a full training of the model on the 
           specified dataset.

        # Inputs

        :param data_df: (DataFrame) dataframe containing data. If it has a split
               column, it will be used for splitting (0: train, 1: validation,
               2: test), otherwise the dataset will be randomly split
        :param data_train_df: (DataFrame) dataframe containing training data
        :param data_validation_df: (DataFrame) dataframe containing validation
               data
        :param data_test_df: (DataFrame dataframe containing test data
        :param data_csv: (string) input data CSV file. If it has a split column,
               it will be used for splitting (0: train, 1: validation, 2: test),
               otherwise the dataset will be randomly split
        :param data_train_csv: (string) input train data CSV file
        :param data_validation_csv: (string) input validation data CSV file
        :param data_test_csv: (string) input test data CSV file
        :param data_hdf5: (string) input data HDF5 file. It is an intermediate
               preprocess  version of the input CSV created the first time a CSV
               file is used in the same directory with the same name and a hdf5
               extension
        :param data_train_hdf5: (string) input train data HDF5 file. It is an
               intermediate preprocess  version of the input CSV created the
               first time a CSV file is used in the same directory with the same
               name and a hdf5 extension
        :param data_validation_hdf5: (string) input validation data HDF5 file.
               It is an intermediate preprocess version of the input CSV created
               the first time a CSV file is used in the same directory with the
               same name and a hdf5 extension
        :param data_test_hdf5: (string) input test data HDF5 file. It is an
               intermediate preprocess  version of the input CSV created the
               first time a CSV file is used in the same directory with the same
               name and a hdf5 extension
        :param train_set_metadata_json: (string) input metadata JSON file. It is an
               intermediate preprocess file containing the mappings of the input
               CSV created the first time a CSV file is used in the same
               directory with the same name and a json extension
        :param dataset_type: (string, default: `'default'`) determines the type
               of preprocessing will be applied to the data. Only `generic` is
               available at the moment
        :param model_name: (string) a name for the model, user for the save
               directory
        :param model_load_path: (string) path of a pretrained model to load as
               initialization
        :param model_resume_path: (string) path of a the model directory to
               resume training of
        :param skip_save_model: (bool, default: `False`) disables
               saving model weights and hyperparameters each time the model
               improves. By default Ludwig saves model weights after each epoch
               the validation measure imrpvoes, but if the model is really big
               that can be time consuming if you do not want to keep
               the weights and just find out what performance can a model get
               with a set of hyperparameters, use this parameter to skip it,
               but the model will not be loadable later on.
        :param skip_save_progress: (bool, default: `False`) disables saving
               progress each epoch. By default Ludwig saves weights and stats
               after each epoch for enabling resuming of training, but if
               the model is really big that can be time consuming and will uses
               twice as much space, use this parameter to skip it, but training
               cannot be resumed later on.
        :param skip_save_log: (bool, default: `False`) disables saving TensorBoard
               logs. By default Ludwig saves logs for the TensorBoard, but if it
               is not needed turning it off can slightly increase the
               overall speed.
        :param skip_save_processed_input: (bool, default: `False`) skips saving
               intermediate HDF5 and JSON files
        :param output_directory: (string, default: `'results'`) directory that
               contains the results
        :param gpus: (string, default: `None`) list of GPUs to use (it uses the
               same syntax of CUDA_VISIBLE_DEVICES)
        :param gpu_fraction: (float, default `1.0`) fraction of gpu memory to
               initialize the process with
        :param random_seed: (int, default`42`) a random seed that is going to be
               used anywhere there is a call to a random number generator: data
               splitting, parameter initialization and training set shuffling
        :param debug: (bool, default: `False`) enables debugging mode
        :param logging_level: (int, default: `logging.ERROR`) logging level to
               use for logging. Use logging constants like `logging.DEBUG`,
               `logging.INFO` and `logging.ERROR`. By default only errors will
               be printed.

        There are three ways to provide data: by dataframes using the `_df`
        parameters, by CSV using the `_csv` parameters and by HDF5 and JSON,
        using `_hdf5` and `_json` parameters.
        The DataFrame approach uses data previously obtained and put in a
        dataframe, the CSV approach loads data from a CSV file, while HDF5 and
        JSON load previously preprocessed HDF5 and JSON files (they are saved in
        the same directory of the CSV they are obtained from).
        For all three approaches either a full dataset can be provided (which
        will be split randomly according to the split probabilities defined in
        the model definition, by default 70% training, 10% validation and 20%
        test) or, if it contanins a plit column, it will be plit according to
        that column (interpreting 0 as training, 1 as validation and 2 as test).
        Alternatively separated dataframes / CSV / HDF5 files can beprovided
        for each split.

        During training the model and statistics will be saved in a directory
        `[output_dir]/[experiment_name]_[model_name]_n` where all variables are
        resolved to user spiecified ones and `n` is an increasing number
        starting from 0 used to differentiate different runs.


        # Return

        :return: (dict) a dictionary containing training statistics for each
        output feature containing loss and measures values for each epoch.

        """
        logging.getLogger().setLevel(logging_level)
        if logging_level in {logging.WARNING, logging.ERROR, logging.CRITICAL}:
            set_disable_progressbar(True)

        # setup directories and file names
        experiment_dir_name = None
        if model_resume_path is not None:
            if os.path.exists(model_resume_path):
                experiment_dir_name = model_resume_path
            else:
                logging.info('Model resume path does not exists,'
                             ' starting training from scratch')
                model_resume_path = None
        if model_resume_path is None:
            experiment_dir_name = get_experiment_dir_name(
                output_directory, '', model_name)
        description_fn, training_stats_fn, model_dir = get_file_names(
            experiment_dir_name)

        # save description
        description = get_experiment_description(
            self.model_definition,
            dataset_type,
            data_csv=data_csv,
            data_train_csv=data_train_csv,
            data_validation_csv=data_validation_csv,
            data_test_csv=data_test_csv,
            data_hdf5=data_hdf5,
            data_train_hdf5=data_train_hdf5,
            data_validation_hdf5=data_validation_hdf5,
            data_test_hdf5=data_test_hdf5,
            metadata_json=train_set_metadata_json,
            random_seed=random_seed)

        save_json(description_fn, description)

        # print description
        logging.info('Model name: {}'.format(model_name))
        logging.info('Output path: {}'.format(experiment_dir_name))
        logging.info('\n')
        for key, value in description.items():
            logging.info('{0}: {1}'.format(key, pformat(value, indent=4)))
        logging.info('\n')

        # preprocess
        if data_df is not None or data_train_df is not None:
            (training_set, validation_set, test_set,
             train_set_metadata) = preprocess_for_training(
                 self.model_definition,
                 dataset_type,
                 data_df=data_df,
                 data_train_df=data_train_df,
                 data_validation_df=data_validation_df,
                 data_test_df=data_test_df,
                 train_set_metadata_json=train_set_metadata_json,
                 skip_save_processed_input=True,
                 preprocessing_params=self.model_definition['preprocessing'],
                 random_seed=random_seed)
        else:
            (training_set, validation_set, test_set,
             train_set_metadata) = preprocess_for_training(
                 self.model_definition,
                 dataset_type,
                 data_csv=data_csv,
                 data_train_csv=data_train_csv,
                 data_validation_csv=data_validation_csv,
                 data_test_csv=data_test_csv,
                 data_hdf5=data_hdf5,
                 data_train_hdf5=data_train_hdf5,
                 data_validation_hdf5=data_validation_hdf5,
                 data_test_hdf5=data_test_hdf5,
                 train_set_metadata_json=train_set_metadata_json,
                 skip_save_processed_input=skip_save_processed_input,
                 preprocessing_params=self.model_definition['preprocessing'],
                 random_seed=random_seed)

        logging.info('Training set: {0}'.format(training_set.size))
        if validation_set is not None:
            logging.info('Validation set: {0}'.format(validation_set.size))
        if test_set is not None:
            logging.info('Test set: {0}'.format(test_set.size))

        # update model definition with metadata properties
        update_model_definition_with_metadata(self.model_definition,
                                              train_set_metadata)

        if not skip_save_model:
            os.makedirs(model_dir, exist_ok=True)
            train_set_metadata_path = os.path.join(
                model_dir, TRAIN_SET_METADATA_FILE_NAME)
            save_json(train_set_metadata_path, train_set_metadata)

        # run the experiment
        model, result = train(training_set=training_set,
                              validation_set=validation_set,
                              test_set=test_set,
                              model_definition=self.model_definition,
                              save_path=model_dir,
                              model_load_path=model_load_path,
                              resume=model_resume_path is not None,
                              skip_save_model=skip_save_model,
                              skip_save_progress=skip_save_progress,
                              skip_save_log=skip_save_log,
                              gpus=gpus,
                              gpu_fraction=gpu_fraction,
                              random_seed=random_seed,
                              debug=debug)

        train_trainset_stats, train_valisest_stats, train_testset_stats = result
        train_stats = {
            'train': train_trainset_stats,
            'validation': train_valisest_stats,
            'test': train_testset_stats
        }

        # save training and test statistics
        save_json(training_stats_fn, train_stats)

        # grab the results of the model with highest validation test performance
        md_training = self.model_definition['training']
        validation_field = md_training['validation_field']
        validation_measure = md_training['validation_measure']
        validation_field_result = train_valisest_stats[validation_field]

        best_function = get_best_function(validation_measure)

        # print results of the model with highest validation test performance
        if validation_set is not None:
            # max or min depending on the measure
            epoch_best_vali_measure, best_vali_measure = best_function(
                enumerate(validation_field_result[validation_measure]),
                key=lambda pair: pair[1])
            logging.info('Best validation model epoch: {0}'.format(
                epoch_best_vali_measure + 1))
            logging.info(
                'Best validation model {0} on validation set {1}: {2}'.format(
                    validation_measure, validation_field, best_vali_measure))

            if test_set is not None:
                best_vali_measure_epoch_test_measure = train_testset_stats[
                    validation_field][validation_measure][
                        epoch_best_vali_measure]
                logging.info(
                    'Best validation model {0} on test set {1}: {2}'.format(
                        validation_measure, validation_field,
                        best_vali_measure_epoch_test_measure))

        logging.info('Finished: {0}'.format(model_name))
        logging.info('Saved to {0}:'.format(experiment_dir_name))

        # set parameters
        self.model = model
        self.train_set_metadata = train_set_metadata

        return train_stats
Example #4
0
    def initialize_model(self,
                         train_set_metadata=None,
                         train_set_metadata_json=None,
                         gpus=None,
                         gpu_memory_limit=None,
                         allow_parallel_threads=True,
                         random_seed=default_random_seed,
                         debug=False,
                         **kwargs):
        """This function initializes a model. It is need for performing online
        learning, so it has to be called before `train_online`.
        `train` initialize the model under the hood, so there is no need to call
        this function if you don't use `train_online`.

        # Inputs

        :param train_set_metadata: (dict) it contains metadata information for
               the input and output features the model is going to be trained
               on. It's the same content of the metadata json file that is
               created while training.
        :param train_set_metadata_json: (string)  path to the JSON metadata file
               created while training. it contains metadata information for the
               input and output features the model is going to be trained on
        :param gpus: (string, default: `None`) list of GPUs to use (it uses the
               same syntax of CUDA_VISIBLE_DEVICES)
        :param gpu_memory_limit: (int: default: `None`) maximum memory in MB to allocate
               per GPU device.
        :param allow_parallel_threads: (bool, default: `True`) allow TensorFlow to use
               multithreading parallelism to improve performance at the cost of
               determinism.
        :param random_seed: (int, default`42`) a random seed that is going to be
               used anywhere there is a call to a random number generator: data
               splitting, parameter initialization and training set shuffling
        :param debug: (bool, default: `False`) enables debugging mode
        """

        if train_set_metadata is None and train_set_metadata_json is None:
            raise ValueError(
                'train_set_metadata or train_set_metadata_json must not None.')
        if train_set_metadata_json is not None:
            train_set_metadata = load_metadata(train_set_metadata_json)

        # update model definition with metadata properties
        update_model_definition_with_metadata(self.model_definition,
                                              train_set_metadata)

        # build model
        model = Trainer(self.model_definition['input_features'],
                        self.model_definition['output_features'],
                        self.model_definition['combiner'],
                        self.model_definition[TRAINING],
                        self.model_definition['preprocessing'],
                        gpus=gpus,
                        gpu_memory_limit=gpu_memory_limit,
                        allow_parallel_threads=allow_parallel_threads,
                        random_seed=random_seed,
                        debug=debug)

        # set parameters
        self.model = model
        self.train_set_metadata = train_set_metadata