Пример #1
0
def train(args):
    '''Run training'''
    # display chainer version
    logging.info('chainer version = ' + chainer.__version__)

    # seed setting (chainer seed may not need it)
    os.environ['CHAINER_SEED'] = str(args.seed)
    logging.info('chainer seed = ' + os.environ['CHAINER_SEED'])

    # debug mode setting
    # 0 would be fastest, but 1 seems to be reasonable
    # by considering reproducability
    # revmoe type check
    if args.debugmode < 2:
        chainer.config.type_check = False
        logging.info('chainer type check is disabled')
    # use determinisitic computation or not
    if args.debugmode < 1:
        chainer.config.cudnn_deterministic = False
        logging.info('chainer cudnn deterministic is disabled')
    else:
        chainer.config.cudnn_deterministic = True

    # check cuda and cudnn availability
    if not chainer.cuda.available:
        logging.warning('cuda is not available')
    if not chainer.cuda.cudnn_enabled:
        logging.warning('cudnn is not available')

    # get input and output dimension info
    with open(args.valid_json, 'rb') as f:
        valid_json = json.load(f)['utts']
    utts = list(valid_json.keys())
    # TODO(nelson) remove in future
    if 'input' not in valid_json[utts[0]]:
        logging.error("input file format (json) is modified, please redo"
                      "stage 2: Dictionary and Json Data Preparation")
        sys.exit(1)
    idim = int(valid_json[utts[0]]['input'][0]['shape'][1])
    odim = int(valid_json[utts[0]]['output'][0]['shape'][1])
    logging.info('#input dims : ' + str(idim))
    logging.info('#output dims: ' + str(odim))

    # check attention type
    if args.atype not in ['noatt', 'dot', 'location']:
        raise NotImplementedError(
            'chainer supports only noatt, dot, and location attention.')

    # specify attention, CTC, hybrid mode
    if args.mtlalpha == 1.0:
        mtl_mode = 'ctc'
        logging.info('Pure CTC mode')
    elif args.mtlalpha == 0.0:
        mtl_mode = 'att'
        logging.info('Pure attention mode')
    else:
        mtl_mode = 'mtl'
        logging.info('Multitask learning mode')

    # specify model architecture
    e2e = E2E(idim, odim, args)
    model = Loss(e2e, args.mtlalpha)

    # write model config
    if not os.path.exists(args.outdir):
        os.makedirs(args.outdir)
    model_conf = args.outdir + '/model.conf'
    with open(model_conf, 'wb') as f:
        logging.info('writing a model config file to' + model_conf)
        # TODO(watanabe) use others than pickle, possibly json, and save as a text
        pickle.dump((idim, odim, args), f)
    for key in sorted(vars(args).keys()):
        logging.info('ARGS: ' + key + ': ' + str(vars(args)[key]))

    # Set gpu
    ngpu = args.ngpu
    if ngpu == 1:
        gpu_id = 0
        # Make a specified GPU current
        chainer.cuda.get_device_from_id(gpu_id).use()
        model.to_gpu()  # Copy the model to the GPU
        logging.info('single gpu calculation.')
    elif ngpu > 1:
        gpu_id = 0
        devices = {'main': gpu_id}
        for gid in six.moves.xrange(1, ngpu):
            devices['sub_%d' % gid] = gid
        logging.info('multi gpu calculation (#gpus = %d).' % ngpu)
        logging.info('batch size is automatically increased (%d -> %d)' %
                     (args.batch_size, args.batch_size * args.ngpu))
    else:
        gpu_id = -1
        logging.info('cpu calculation')

    # Setup an optimizer
    if args.opt == 'adadelta':
        optimizer = chainer.optimizers.AdaDelta(eps=args.eps)
    elif args.opt == 'adam':
        optimizer = chainer.optimizers.Adam()
    optimizer.setup(model)
    optimizer.add_hook(chainer.optimizer.GradientClipping(args.grad_clip))

    # read json data
    with open(args.train_json, 'rb') as f:
        train_json = json.load(f)['utts']
    with open(args.valid_json, 'rb') as f:
        valid_json = json.load(f)['utts']

    # set up training iterator and updater
    if ngpu <= 1:
        # make minibatch list (variable length)
        train = make_batchset(train_json, args.batch_size, args.maxlen_in,
                              args.maxlen_out, args.minibatches)
        # hack to make batchsize argument as 1
        # actual batchsize is included in a list
        train_iter = chainer.iterators.SerialIterator(train, 1)

        # set up updater
        updater = ChainerSeqUpdaterKaldi(train_iter,
                                         optimizer,
                                         converter=converter_kaldi,
                                         device=gpu_id)
    else:
        # set up minibatches
        train_subsets = []
        for gid in six.moves.xrange(ngpu):
            # make subset
            train_json_subset = {
                k: v
                for i, (k, v) in enumerate(train_json.viewitems())
                if i % ngpu == gid
            }
            # make minibatch list (variable length)
            train_subsets += [
                make_batchset(train_json_subset, args.batch_size,
                              args.maxlen_in, args.maxlen_out,
                              args.minibatches)
            ]

        # each subset must have same length for MultiprocessParallelUpdater
        maxlen = max([len(train_subset) for train_subset in train_subsets])
        for train_subset in train_subsets:
            if maxlen != len(train_subset):
                for i in six.moves.xrange(maxlen - len(train_subset)):
                    train_subset += [train_subset[i]]

        # hack to make batchsize argument as 1
        # actual batchsize is included in a list
        train_iters = [
            chainer.iterators.MultiprocessIterator(train_subsets[gid],
                                                   1,
                                                   n_processes=1)
            for gid in six.moves.xrange(ngpu)
        ]

        # set up updater
        updater = ChainerMultiProcessParallelUpdaterKaldi(
            train_iters, optimizer, converter=converter_kaldi, devices=devices)

    # Set up a trainer
    trainer = training.Trainer(updater, (args.epochs, 'epoch'),
                               out=args.outdir)

    # Resume from a snapshot
    if args.resume:
        chainer.serializers.load_npz(args.resume, trainer)

    # set up validation iterator
    valid = make_batchset(valid_json, args.batch_size, args.maxlen_in,
                          args.maxlen_out, args.minibatches)
    valid_iter = chainer.iterators.SerialIterator(valid,
                                                  1,
                                                  repeat=False,
                                                  shuffle=False)

    # Evaluate the model with the test dataset for each epoch
    trainer.extend(
        extensions.Evaluator(valid_iter,
                             model,
                             converter=converter_kaldi,
                             device=gpu_id))

    # Save attention weight each epoch
    if args.num_save_attention > 0 and args.mtlalpha != 1.0:
        data = sorted(list(valid_json.items())[:args.num_save_attention],
                      key=lambda x: int(x[1]['input'][0]['shape'][1]),
                      reverse=True)
        data = converter_kaldi([data], device=gpu_id)
        trainer.extend(PlotAttentionReport(model, data,
                                           args.outdir + "/att_ws"),
                       trigger=(1, 'epoch'))

    # Take a snapshot for each specified epoch
    trainer.extend(extensions.snapshot(), trigger=(1, 'epoch'))

    # Make a plot for training and validation values
    trainer.extend(
        extensions.PlotReport([
            'main/loss', 'validation/main/loss', 'main/loss_ctc',
            'validation/main/loss_ctc', 'main/loss_att',
            'validation/main/loss_att'
        ],
                              'epoch',
                              file_name='loss.png'))
    trainer.extend(
        extensions.PlotReport(['main/acc', 'validation/main/acc'],
                              'epoch',
                              file_name='acc.png'))

    # Save best models
    trainer.extend(
        extensions.snapshot_object(model, 'model.loss.best'),
        trigger=training.triggers.MinValueTrigger('validation/main/loss'))
    if mtl_mode is not 'ctc':
        trainer.extend(
            extensions.snapshot_object(model, 'model.acc.best'),
            trigger=training.triggers.MaxValueTrigger('validation/main/acc'))

    # epsilon decay in the optimizer
    if args.opt == 'adadelta':
        if args.criterion == 'acc' and mtl_mode is not 'ctc':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.acc.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
        elif args.criterion == 'loss':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.loss.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))

    # Write a log of evaluation statistics for each epoch
    trainer.extend(extensions.LogReport(trigger=(100, 'iteration')))
    report_keys = [
        'epoch', 'iteration', 'main/loss', 'main/loss_ctc', 'main/loss_att',
        'validation/main/loss', 'validation/main/loss_ctc',
        'validation/main/loss_att', 'main/acc', 'validation/main/acc',
        'elapsed_time'
    ]
    if args.opt == 'adadelta':
        trainer.extend(extensions.observe_value(
            'eps', lambda trainer: trainer.updater.get_optimizer('main').eps),
                       trigger=(100, 'iteration'))
        report_keys.append('eps')
    trainer.extend(extensions.PrintReport(report_keys),
                   trigger=(100, 'iteration'))

    trainer.extend(extensions.ProgressBar())

    # Run the training
    trainer.run()
Пример #2
0
def main():
    parser = argparse.ArgumentParser()
    # general configuration
    parser.add_argument('--gpu',
                        '-g',
                        default='-1',
                        type=str,
                        help='GPU ID (negative value indicates CPU)')
    parser.add_argument('--outdir',
                        type=str,
                        required=True,
                        help='Output directory')
    parser.add_argument('--debugmode', default=1, type=int, help='Debugmode')
    parser.add_argument('--dict', required=True, help='Dictionary')
    parser.add_argument('--seed', default=1, type=int, help='Random seed')
    parser.add_argument('--debugdir',
                        type=str,
                        help='Output directory for debugging')
    parser.add_argument('--resume',
                        '-r',
                        default='',
                        nargs='?',
                        help='Resume the training from snapshot')
    parser.add_argument('--minibatches',
                        '-N',
                        type=int,
                        default='-1',
                        help='Process only N minibatches (for debug)')
    parser.add_argument('--verbose',
                        '-V',
                        default=0,
                        type=int,
                        help='Verbose option')
    # task related
    parser.add_argument('--train-feat',
                        type=str,
                        required=True,
                        help='Filename of train feature data (Kaldi scp)')
    parser.add_argument('--valid-feat',
                        type=str,
                        required=True,
                        help='Filename of validation feature data (Kaldi scp)')
    parser.add_argument('--train-label',
                        type=str,
                        required=True,
                        help='Filename of train label data (json)')
    parser.add_argument('--valid-label',
                        type=str,
                        required=True,
                        help='Filename of validation label data (json)')
    # network archtecture
    # encoder
    parser.add_argument('--etype',
                        default='blstmp',
                        type=str,
                        choices=['blstm', 'blstmp', 'vggblstmp', 'vggblstm'],
                        help='Type of encoder network architecture')
    parser.add_argument('--elayers',
                        default=4,
                        type=int,
                        help='Number of encoder layers')
    parser.add_argument('--eunits',
                        '-u',
                        default=300,
                        type=int,
                        help='Number of encoder hidden units')
    parser.add_argument('--eprojs',
                        default=320,
                        type=int,
                        help='Number of encoder projection units')
    parser.add_argument(
        '--subsample',
        default=1,
        type=str,
        help=
        'Subsample input frames x_y_z means subsample every x frame at 1st layer, '
        'every y frame at 2nd layer etc.')
    # loss
    parser.add_argument('--ctc_type',
                        default='chainer',
                        type=str,
                        choices=['chainer', 'warpctc'],
                        help='Type of CTC implementation to calculate loss.')
    # attention
    parser.add_argument('--atype',
                        default='dot',
                        type=str,
                        choices=['dot', 'location', 'noatt'],
                        help='Type of attention architecture')
    parser.add_argument('--adim',
                        default=320,
                        type=int,
                        help='Number of attention transformation dimensions')
    parser.add_argument('--aconv-chans',
                        default=-1,
                        type=int,
                        help='Number of attention convolution channels \
                        (negative value indicates no location-aware attention)'
                        )
    parser.add_argument('--aconv-filts',
                        default=100,
                        type=int,
                        help='Number of attention convolution filters \
                        (negative value indicates no location-aware attention)'
                        )
    # decoder
    parser.add_argument('--dtype',
                        default='lstm',
                        type=str,
                        choices=['lstm'],
                        help='Type of decoder network architecture')
    parser.add_argument('--dlayers',
                        default=1,
                        type=int,
                        help='Number of decoder layers')
    parser.add_argument('--dunits',
                        default=320,
                        type=int,
                        help='Number of decoder hidden units')
    parser.add_argument(
        '--mtlalpha',
        default=0.5,
        type=float,
        help=
        'Multitask learning coefficient, alpha: alpha*ctc_loss + (1-alpha)*att_loss '
    )
    parser.add_argument(
        '--lsm-type',
        const='',
        default='',
        type=str,
        nargs='?',
        choices=['', 'unigram'],
        help='Apply label smoothing with a specified distribution type')
    parser.add_argument('--lsm-weight',
                        default=0.0,
                        type=float,
                        help='Label smoothing weight')
    # model (parameter) related
    parser.add_argument('--dropout-rate',
                        default=0.0,
                        type=float,
                        help='Dropout rate')
    # minibatch related
    parser.add_argument('--batch-size',
                        '-b',
                        default=50,
                        type=int,
                        help='Batch size')
    parser.add_argument(
        '--maxlen-in',
        default=800,
        type=int,
        metavar='ML',
        help='Batch size is reduced if the input sequence length > ML')
    parser.add_argument(
        '--maxlen-out',
        default=150,
        type=int,
        metavar='ML',
        help='Batch size is reduced if the output sequence length > ML')
    # optimization related
    parser.add_argument('--opt',
                        default='adadelta',
                        type=str,
                        choices=['adadelta', 'adam'],
                        help='Optimizer')
    parser.add_argument('--eps',
                        default=1e-8,
                        type=float,
                        help='Epsilon constant for optimizer')
    parser.add_argument('--eps-decay',
                        default=0.01,
                        type=float,
                        help='Decaying ratio of epsilon')
    parser.add_argument('--criterion',
                        default='acc',
                        type=str,
                        choices=['loss', 'acc'],
                        help='Criterion to perform epsilon decay')
    parser.add_argument('--threshold',
                        default=1e-4,
                        type=float,
                        help='Threshold to stop iteration')
    parser.add_argument('--epochs',
                        '-e',
                        default=30,
                        type=int,
                        help='Number of maximum epochs')
    parser.add_argument('--grad-clip',
                        default=5,
                        type=float,
                        help='Gradient norm threshold to clip')
    args = parser.parse_args()

    # logging info
    if args.verbose > 0:
        logging.basicConfig(
            level=logging.INFO,
            format=
            '%(asctime)s (%(module)s:%(lineno)d) %(levelname)s: %(message)s')
    else:
        logging.basicConfig(
            level=logging.WARN,
            format=
            '%(asctime)s (%(module)s:%(lineno)d) %(levelname)s: %(message)s')
        logging.warning('Skip DEBUG/INFO messages')

    # display PYTHONPATH
    logging.info('python path = ' + os.environ['PYTHONPATH'])

    # display chainer version
    logging.info('chainer version = ' + chainer.__version__)

    # seed setting (chainer seed may not need it)
    nseed = args.seed
    random.seed(nseed)
    np.random.seed(nseed)
    os.environ['CHAINER_SEED'] = str(nseed)
    logging.info('chainer seed = ' + os.environ['CHAINER_SEED'])

    # debug mode setting
    # 0 would be fastest, but 1 seems to be reasonable
    # by considering reproducability
    # revmoe type check
    if args.debugmode < 2:
        chainer.config.type_check = False
        logging.info('chainer type check is disabled')
    # use determinisitic computation or not
    if args.debugmode < 1:
        chainer.config.cudnn_deterministic = False
        logging.info('chainer cudnn deterministic is disabled')
    else:
        chainer.config.cudnn_deterministic = True

    # load dictionary for debug log
    if args.dict is not None:
        with open(args.dict, 'rb') as f:
            dictionary = f.readlines()
        char_list = [
            entry.decode('utf-8').split(' ')[0] for entry in dictionary
        ]
        char_list.insert(0, '<blank>')
        char_list.append('<eos>')
        args.char_list = char_list
    else:
        args.char_list = None

    # check cuda and cudnn availability
    if not chainer.cuda.available:
        logging.warning('cuda is not available')
    if not chainer.cuda.cudnn_enabled:
        logging.warning('cudnn is not available')

    # get input and output dimension info
    with open(args.valid_label, 'rb') as f:
        valid_json = json.load(f)['utts']
    utts = list(valid_json.keys())
    idim = int(valid_json[utts[0]]['idim'])
    odim = int(valid_json[utts[0]]['odim'])
    logging.info('#input dims : ' + str(idim))
    logging.info('#output dims: ' + str(odim))

    # specify model architecture
    e2e = E2E(idim, odim, args)
    model = Loss(e2e, args.mtlalpha)

    # write model config
    if not os.path.exists(args.outdir):
        os.makedirs(args.outdir)
    model_conf = args.outdir + '/model.conf'
    with open(model_conf, 'wb') as f:
        logging.info('writing a model config file to' + model_conf)
        # TODO(watanabe) use others than pickle, possibly json, and save as a text
        pickle.dump((idim, odim, args), f)
    for key in sorted(vars(args).keys()):
        logging.info('ARGS: ' + key + ': ' + str(vars(args)[key]))

    # Set gpu
    gpu_id = int(args.gpu)
    logging.info('gpu id: ' + str(gpu_id))
    if gpu_id >= 0:
        # Make a specified GPU current
        chainer.cuda.get_device_from_id(gpu_id).use()
        model.to_gpu()  # Copy the model to the GPU

    # Setup an optimizer
    if args.opt == 'adadelta':
        optimizer = chainer.optimizers.AdaDelta(eps=args.eps)
    elif args.opt == 'adam':
        optimizer = chainer.optimizers.Adam()
    optimizer.setup(model)
    optimizer.add_hook(chainer.optimizer.GradientClipping(args.grad_clip))

    # read json data
    with open(args.train_label, 'rb') as f:
        train_json = json.load(f)['utts']
    with open(args.valid_label, 'rb') as f:
        valid_json = json.load(f)['utts']

    # make minibatch list (variable length)
    train = make_batchset(train_json, args.batch_size, args.maxlen_in,
                          args.maxlen_out, args.minibatches)
    valid = make_batchset(valid_json, args.batch_size, args.maxlen_in,
                          args.maxlen_out, args.minibatches)
    # hack to make batchsze argument as 1
    # actual bathsize is included in a list
    train_iter = chainer.iterators.SerialIterator(train, 1)
    valid_iter = chainer.iterators.SerialIterator(valid,
                                                  1,
                                                  repeat=False,
                                                  shuffle=False)

    # prepare Kaldi reader
    train_reader = lazy_io.read_dict_scp(args.train_feat)
    valid_reader = lazy_io.read_dict_scp(args.valid_feat)

    # Set up a trainer
    updater = SeqUpdaterKaldi(train_iter, optimizer, train_reader, gpu_id)
    trainer = training.Trainer(updater, (args.epochs, 'epoch'),
                               out=args.outdir)

    # Resume from a snapshot
    if args.resume:
        chainer.serializers.load_npz(args.resume, trainer)

    # Evaluate the model with the test dataset for each epoch
    trainer.extend(
        SeqEvaluaterKaldi(valid_iter, model, valid_reader, device=gpu_id))

    # Take a snapshot for each specified epoch
    trainer.extend(extensions.snapshot(), trigger=(1, 'epoch'))

    # Make a plot for training and validation values
    trainer.extend(
        extensions.PlotReport([
            'main/loss', 'validation/main/loss', 'main/loss_ctc',
            'validation/main/loss_ctc', 'main/loss_att',
            'validation/main/loss_att'
        ],
                              'epoch',
                              file_name='loss.png'))
    trainer.extend(
        extensions.PlotReport(['main/acc', 'validation/main/acc'],
                              'epoch',
                              file_name='acc.png'))

    # Save best models
    trainer.extend(
        extensions.snapshot_object(model, 'model.loss.best'),
        trigger=training.triggers.MinValueTrigger('validation/main/loss'))
    trainer.extend(
        extensions.snapshot_object(model, 'model.acc.best'),
        trigger=training.triggers.MaxValueTrigger('validation/main/acc'))

    # epsilon decay in the optimizer
    if args.opt == 'adadelta':
        if args.criterion == 'acc':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.acc.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
        elif args.criterion == 'loss':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.loss.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))

    # Write a log of evaluation statistics for each epoch
    trainer.extend(extensions.LogReport(trigger=(100, 'iteration')))
    report_keys = [
        'epoch', 'iteration', 'main/loss', 'main/loss_ctc', 'main/loss_att',
        'validation/main/loss', 'validation/main/loss_ctc',
        'validation/main/loss_att', 'main/acc', 'validation/main/acc',
        'elapsed_time'
    ]
    if args.opt == 'adadelta':
        trainer.extend(extensions.observe_value(
            'eps', lambda trainer: trainer.updater.get_optimizer('main').eps),
                       trigger=(100, 'iteration'))
        report_keys.append('eps')
    trainer.extend(extensions.PrintReport(report_keys),
                   trigger=(100, 'iteration'))

    trainer.extend(extensions.ProgressBar())

    # Run the training
    trainer.run()
Пример #3
0
def train(args):
    '''Run training'''
    # display chainer version
    logging.info('chainer version = ' + chainer.__version__)

    # seed setting (chainer seed may not need it)
    os.environ['CHAINER_SEED'] = str(args.seed)
    logging.info('chainer seed = ' + os.environ['CHAINER_SEED'])

    # debug mode setting
    # 0 would be fastest, but 1 seems to be reasonable
    # by considering reproducability
    # revmoe type check
    if args.debugmode < 2:
        chainer.config.type_check = False
        logging.info('chainer type check is disabled')
    # use determinisitic computation or not
    if args.debugmode < 1:
        chainer.config.cudnn_deterministic = False
        logging.info('chainer cudnn deterministic is disabled')
    else:
        chainer.config.cudnn_deterministic = True

    # check cuda and cudnn availability
    if not chainer.cuda.available:
        logging.warning('cuda is not available')
    if not chainer.cuda.cudnn_enabled:
        logging.warning('cudnn is not available')

    # get input and output dimension info
    with open(args.valid_label, 'rb') as f:
        valid_json = json.load(f)['utts']
    utts = list(valid_json.keys())
    idim = int(valid_json[utts[0]]['idim'])
    odim = int(valid_json[utts[0]]['odim'])
    logging.info('#input dims : ' + str(idim))
    logging.info('#output dims: ' + str(odim))

    # check attention type
    if args.atype not in ['noatt', 'dot', 'location']:
        raise NotImplementedError(
            'chainer supports only noatt, dot, and location attention.')

    # specify model architecture
    e2e = E2E(idim, odim, args)
    model = Loss(e2e, args.mtlalpha)

    # write model config
    if not os.path.exists(args.outdir):
        os.makedirs(args.outdir)
    model_conf = args.outdir + '/model.conf'
    with open(model_conf, 'wb') as f:
        logging.info('writing a model config file to' + model_conf)
        # TODO(watanabe) use others than pickle, possibly json, and save as a text
        pickle.dump((idim, odim, args), f)
    for key in sorted(vars(args).keys()):
        logging.info('ARGS: ' + key + ': ' + str(vars(args)[key]))

    # Set gpu
    gpu_id = int(args.gpu)
    logging.info('gpu id: ' + str(gpu_id))
    if gpu_id >= 0:
        # Make a specified GPU current
        chainer.cuda.get_device_from_id(gpu_id).use()
        model.to_gpu()  # Copy the model to the GPU

    # Setup an optimizer
    if args.opt == 'adadelta':
        optimizer = chainer.optimizers.AdaDelta(eps=args.eps)
    elif args.opt == 'adam':
        optimizer = chainer.optimizers.Adam()
    optimizer.setup(model)
    optimizer.add_hook(chainer.optimizer.GradientClipping(args.grad_clip))

    # read json data
    with open(args.train_label, 'rb') as f:
        train_json = json.load(f)['utts']
    with open(args.valid_label, 'rb') as f:
        valid_json = json.load(f)['utts']

    # make minibatch list (variable length)
    train = make_batchset(train_json, args.batch_size, args.maxlen_in,
                          args.maxlen_out, args.minibatches)
    valid = make_batchset(valid_json, args.batch_size, args.maxlen_in,
                          args.maxlen_out, args.minibatches)
    # hack to make batchsze argument as 1
    # actual bathsize is included in a list
    train_iter = chainer.iterators.SerialIterator(train, 1)
    valid_iter = chainer.iterators.SerialIterator(valid,
                                                  1,
                                                  repeat=False,
                                                  shuffle=False)

    # prepare Kaldi reader
    train_reader = lazy_io.read_dict_scp(args.train_feat)
    valid_reader = lazy_io.read_dict_scp(args.valid_feat)

    # Set up a trainer
    updater = ChainerSeqUpdaterKaldi(train_iter, optimizer, train_reader,
                                     gpu_id)
    trainer = training.Trainer(updater, (args.epochs, 'epoch'),
                               out=args.outdir)

    # Resume from a snapshot
    if args.resume:
        chainer.serializers.load_npz(args.resume, trainer)

    # Evaluate the model with the test dataset for each epoch
    trainer.extend(
        ChainerSeqEvaluaterKaldi(valid_iter,
                                 model,
                                 valid_reader,
                                 device=gpu_id))

    # Take a snapshot for each specified epoch
    trainer.extend(extensions.snapshot(), trigger=(1, 'epoch'))

    # Make a plot for training and validation values
    trainer.extend(
        extensions.PlotReport([
            'main/loss', 'validation/main/loss', 'main/loss_ctc',
            'validation/main/loss_ctc', 'main/loss_att',
            'validation/main/loss_att'
        ],
                              'epoch',
                              file_name='loss.png'))
    trainer.extend(
        extensions.PlotReport(['main/acc', 'validation/main/acc'],
                              'epoch',
                              file_name='acc.png'))

    # Save best models
    trainer.extend(
        extensions.snapshot_object(model, 'model.loss.best'),
        trigger=training.triggers.MinValueTrigger('validation/main/loss'))
    trainer.extend(
        extensions.snapshot_object(model, 'model.acc.best'),
        trigger=training.triggers.MaxValueTrigger('validation/main/acc'))

    # epsilon decay in the optimizer
    if args.opt == 'adadelta':
        if args.criterion == 'acc':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.acc.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/acc', lambda best_value,
                               current_value: best_value > current_value))
        elif args.criterion == 'loss':
            trainer.extend(restore_snapshot(model,
                                            args.outdir + '/model.loss.best'),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))
            trainer.extend(adadelta_eps_decay(args.eps_decay),
                           trigger=CompareValueTrigger(
                               'validation/main/loss', lambda best_value,
                               current_value: best_value < current_value))

    # Write a log of evaluation statistics for each epoch
    trainer.extend(extensions.LogReport(trigger=(100, 'iteration')))
    report_keys = [
        'epoch', 'iteration', 'main/loss', 'main/loss_ctc', 'main/loss_att',
        'validation/main/loss', 'validation/main/loss_ctc',
        'validation/main/loss_att', 'main/acc', 'validation/main/acc',
        'elapsed_time'
    ]
    if args.opt == 'adadelta':
        trainer.extend(extensions.observe_value(
            'eps', lambda trainer: trainer.updater.get_optimizer('main').eps),
                       trigger=(100, 'iteration'))
        report_keys.append('eps')
    trainer.extend(extensions.PrintReport(report_keys),
                   trigger=(100, 'iteration'))

    trainer.extend(extensions.ProgressBar())

    # Run the training
    trainer.run()