Exemple #1
0
def initialaze_algorithm(config, save_path, bokeh_name, params, bokeh_server,
                         bokeh, use_load_ext, load_log, fast_start, 
                         recognizer, data, model, cg, regularized_cg,
                         cost, train_cost, parameters, 
                         max_norm_rules, observables,
                         batch_size, batch_cost, weights_entropy, 
                         labels_mask, labels,  gradients=None):
    primary_observables = observables
    secondary_observables = []
    validation_observables = []
    root_path, extension = os.path.splitext(save_path)
    train_conf = config['training']
    # Define the training algorithm.
    clipping = StepClipping(train_conf['gradient_threshold'])
    clipping.threshold.name = "gradient_norm_threshold"
    rule_names = train_conf.get('rules', ['momentum'])
    core_rules = []
    if 'momentum' in rule_names:
        logger.info("Using scaling and momentum for training")
        core_rules.append(Momentum(train_conf['scale'], train_conf['momentum']))
    if 'adadelta' in rule_names:
        logger.info("Using AdaDelta for training")
        core_rules.append(AdaDelta(train_conf['decay_rate'], train_conf['epsilon']))
    if 'adam' in rule_names:
        assert len(rule_names) == 1
        logger.info("Using Adam for training")
        core_rules.append(
            Adam(learning_rate=train_conf.get('scale', 0.002),
                 beta1=train_conf.get('beta1', 0.1),
                 beta2=train_conf.get('beta2', 0.001),
                 epsilon=train_conf.get('epsilon', 1e-8),
                 decay_factor=train_conf.get('decay_rate', (1 - 1e-8))))
    burn_in = []
    if train_conf.get('burn_in_steps', 0):
        burn_in.append(
            BurnIn(num_steps=train_conf['burn_in_steps']))
    algorithm = GradientDescent(
        cost=train_cost,
        parameters=parameters.values(),
        gradients=gradients,
        step_rule=CompositeRule(
            [clipping] + core_rules + max_norm_rules +
            # Parameters are not changed at all
            # when nans are encountered.
            [RemoveNotFinite(0.0)] + burn_in),
        on_unused_sources='warn')
        #theano_func_kwargs={'mode':NanGuardMode(nan_is_error=True)})

    logger.debug("Scan Ops in the gradients")
    gradient_cg = ComputationGraph(algorithm.gradients.values())
    for op in ComputationGraph(gradient_cg).scans:
        logger.debug(op)

    # More variables for debugging: some of them can be added only
    # after the `algorithm` object is created.
    secondary_observables += list(regularized_cg.outputs)
    if not 'train_cost' in [v.name for v in secondary_observables]:
        secondary_observables += [train_cost]
    secondary_observables += [
        algorithm.total_step_norm, algorithm.total_gradient_norm,
        clipping.threshold]
    for name, param in parameters.items():
        num_elements = numpy.product(param.get_value().shape)
        norm = param.norm(2) / num_elements ** 0.5
        grad_norm = algorithm.gradients[param].norm(2) / num_elements ** 0.5
        step_norm = algorithm.steps[param].norm(2) / num_elements ** 0.5
        stats = tensor.stack(norm, grad_norm, step_norm, step_norm / grad_norm)
        stats.name = name + '_stats'
        secondary_observables.append(stats)

    primary_observables += [
        train_cost,
        algorithm.total_gradient_norm,
        algorithm.total_step_norm, clipping.threshold]

    validation_observables += [
        rename(aggregation.mean(batch_cost, batch_size), cost.name),
        rename(aggregation.sum_(batch_size), 'num_utterances')] + weights_entropy


    def attach_aggregation_schemes(variables):
        # Aggregation specification has to be factored out as a separate
        # function as it has to be applied at the very last stage
        # separately to training and validation observables.
        result = []
        for var in variables:
            if var.name.startswith('weights_entropy'):
                chld_id = recognizer.child_id_from_postfix(var.name)
                result.append(rename(aggregation.mean(var, labels_mask[chld_id].sum()),
                                     'weights_entropy_per_label'+
                                     recognizer.children[chld_id].names_postfix))
            elif var.name.endswith('_nll'):
                chld_id = recognizer.child_id_from_postfix(var.name)
                result.append(rename(aggregation.mean(var.sum(),
                                                      labels_mask[chld_id].sum()),
                                     var.name+'_per_label'))
            else:
                result.append(var)
        return result

    mon_conf = config['monitoring']
    # Build main loop.
    logger.info("Initialize extensions")
    extensions = []
    if use_load_ext and params:
        extensions.append(Load(params, load_iteration_state=True, load_log=True))
    if load_log and params:
        extensions.append(LoadLog(params))
    extensions += [
        Timing(after_batch=True),
        CGStatistics(),
        #CodeVersion(['lvsr']),
    ]
    extensions.append(TrainingDataMonitoring(
        primary_observables, after_batch=True))
    average_monitoring = TrainingDataMonitoring(
        attach_aggregation_schemes(secondary_observables),
        prefix="average", every_n_batches=10)
    extensions.append(average_monitoring)
    validation = DataStreamMonitoring(
        attach_aggregation_schemes(validation_observables),
        data.get_stream("valid", shuffle=False, **data_params_valid), prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=mon_conf['validate_every_epochs'],
            every_n_batches=mon_conf['validate_every_batches'],
            after_training=False)
    extensions.append(validation)

    additional_patience_notifiers = []
    uas = DependencyErrorRate(recognizer.children[0], data,
                              **config['monitoring']['search'])
    las = AuxiliaryErrorRates(uas, name='LAS')
    lab = AuxiliaryErrorRates(uas, name='LAB')
    per_monitoring = DataStreamMonitoring(
        [uas, las, lab], data.get_one_stream("valid", data.langs[0], batches=False, shuffle=False, **data_params_valid)[0],
        prefix="valid").set_conditions(
                before_first_epoch=not fast_start,
                every_n_epochs=mon_conf['search_every_epochs'],
                every_n_batches=mon_conf['search_every_batches'],
                after_training=False)
    extensions.append(per_monitoring)
    track_the_best_uas = TrackTheBest(
        per_monitoring.record_name(uas)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    track_the_best_las = TrackTheBest(
        per_monitoring.record_name(las)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    track_the_best_lab = TrackTheBest(
        per_monitoring.record_name(lab)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    extensions += [track_the_best_uas,
                   track_the_best_las,
                   track_the_best_lab,
                   ]
    per = uas
    track_the_best_per = track_the_best_uas
    additional_patience_notifiers = [track_the_best_lab,
                                     track_the_best_las]
    track_the_best_cost = TrackTheBest(
        validation.record_name(cost)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    extensions += [track_the_best_cost]
    extensions.append(AdaptiveClipping(
        algorithm.total_gradient_norm.name,
        clipping, train_conf['gradient_threshold'],
        decay_rate=0.998, burnin_period=500,
        num_stds=train_conf.get('clip_stds', 1.0)))
    extensions += [
        SwitchOffLengthFilter(
            data.length_filter,
            after_n_batches=train_conf.get('stop_filtering')),
        FinishAfter(after_n_batches=train_conf['num_batches'],
                    after_n_epochs=train_conf['num_epochs']),
            # .add_condition(["after_batch"], _gradient_norm_is_none),
    ]
    main_postfix = recognizer.children[0].names_postfix
    channels = [
        # Plot 1: training and validation costs
        [average_monitoring.record_name(train_cost),
         validation.record_name(cost)],
        # Plot 2: gradient norm,
        [average_monitoring.record_name(algorithm.total_gradient_norm),
         average_monitoring.record_name(clipping.threshold)],
        # Plot 3: phoneme error rate
        [per_monitoring.record_name(per)],
        # Plot 4: training and validation mean weight entropy
        [average_monitoring._record_name('weights_entropy_per_label'+main_postfix),
         validation._record_name('weights_entropy_per_label'+main_postfix)],
        # Plot 5: training and validation monotonicity penalty
        [average_monitoring._record_name('weights_penalty_per_recording'+main_postfix),
         validation._record_name('weights_penalty_per_recording'+main_postfix)]]
    if bokeh:
        extensions += [
            Plot(bokeh_name if bokeh_name
                 else os.path.basename(save_path),
                 channels,
                 every_n_batches=10,
                 server_url=bokeh_server),]
    extensions += [
        Checkpoint(save_path,
                   before_first_epoch=not fast_start, after_epoch=True,
                   every_n_batches=train_conf.get('save_every_n_batches'),
                   save_separately=["model", "log"],
                   use_cpickle=True)
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_per.notification_name),
            (root_path + "_best" + extension,))
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_cost.notification_name),
            (root_path + "_best_ll" + extension,)),
        ProgressBar()]
    extensions.append(EmbedIPython(use_main_loop_run_caller_env=True))

    if train_conf.get('patience'):
        patience_conf = train_conf['patience']
        if not patience_conf.get('notification_names'):
            # setdefault will not work for empty list
            patience_conf['notification_names'] = [
                track_the_best_per.notification_name,
                track_the_best_cost.notification_name] + additional_patience_notifiers
        extensions.append(Patience(**patience_conf))

    if train_conf.get('min_performance_stops'):
        extensions.append(EarlyTermination(
            param_name=track_the_best_per.best_name,
            min_performance_by_epoch=train_conf['min_performance_stops']))

    extensions.append(Printing(every_n_batches=1,
                               attribute_filter=PrintingFilterList()))

    return model, algorithm, data, extensions
Exemple #2
0
def initialize_all(config, save_path, bokeh_name, params, bokeh_server, bokeh,
                   test_tag, use_load_ext, load_log, fast_start):
    root_path, extension = os.path.splitext(save_path)

    data = Data(**config['data'])
    train_conf = config['training']
    recognizer = create_model(config, data, test_tag)

    # Separate attention_params to be handled differently
    # when regularization is applied
    attention = recognizer.generator.transition.attention
    attention_params = Selector(attention).get_parameters().values()

    logger.info(
        "Initialization schemes for all bricks.\n"
        "Works well only in my branch with __repr__ added to all them,\n"
        "there is an issue #463 in Blocks to do that properly.")

    def show_init_scheme(cur):
        result = dict()
        for attr in dir(cur):
            if attr.endswith('_init'):
                result[attr] = getattr(cur, attr)
        for child in cur.children:
            result[child.name] = show_init_scheme(child)
        return result

    logger.info(pprint.pformat(show_init_scheme(recognizer)))

    prediction, prediction_mask = add_exploration(recognizer, data, train_conf)

    #
    # Observables:
    #
    primary_observables = []  # monitored each batch
    secondary_observables = []  # monitored every 10 batches
    validation_observables = []  # monitored on the validation set

    cg = recognizer.get_cost_graph(batch=True,
                                   prediction=prediction,
                                   prediction_mask=prediction_mask)
    labels, = VariableFilter(applications=[recognizer.cost], name='labels')(cg)
    labels_mask, = VariableFilter(applications=[recognizer.cost],
                                  name='labels_mask')(cg)

    gain_matrix = VariableFilter(
        theano_name=RewardRegressionEmitter.GAIN_MATRIX)(cg)
    if len(gain_matrix):
        gain_matrix, = gain_matrix
        primary_observables.append(rename(gain_matrix.min(), 'min_gain'))
        primary_observables.append(rename(gain_matrix.max(), 'max_gain'))

    batch_cost = cg.outputs[0].sum()
    batch_size = rename(recognizer.labels.shape[1], "batch_size")
    # Assumes constant batch size. `aggregation.mean` is not used because
    # of Blocks #514.
    cost = batch_cost / batch_size
    cost.name = "sequence_total_cost"
    logger.info("Cost graph is built")

    # Fetch variables useful for debugging.
    # It is important not to use any aggregation schemes here,
    # as it's currently impossible to spread the effect of
    # regularization on their variables, see Blocks #514.
    cost_cg = ComputationGraph(cost)
    r = recognizer
    energies, = VariableFilter(applications=[r.generator.readout.readout],
                               name="output_0")(cost_cg)
    bottom_output = VariableFilter(
        # We need name_regex instead of name because LookupTable calls itsoutput output_0
        applications=[r.bottom.apply],
        name_regex="output")(cost_cg)[-1]
    attended, = VariableFilter(applications=[r.generator.transition.apply],
                               name="attended")(cost_cg)
    attended_mask, = VariableFilter(applications=[
        r.generator.transition.apply
    ],
                                    name="attended_mask")(cost_cg)
    weights, = VariableFilter(applications=[r.generator.evaluate],
                              name="weights")(cost_cg)

    from blocks.roles import AUXILIARY
    l2_cost, = VariableFilter(roles=[AUXILIARY],
                              theano_name='l2_cost_aux')(cost_cg)
    cost_forward, = VariableFilter(roles=[AUXILIARY],
                                   theano_name='costs_forward_aux')(cost_cg)

    max_recording_length = rename(bottom_output.shape[0],
                                  "max_recording_length")
    # To exclude subsampling related bugs
    max_attended_mask_length = rename(attended_mask.shape[0],
                                      "max_attended_mask_length")
    max_attended_length = rename(attended.shape[0], "max_attended_length")
    max_num_phonemes = rename(labels.shape[0], "max_num_phonemes")
    min_energy = rename(energies.min(), "min_energy")
    max_energy = rename(energies.max(), "max_energy")
    mean_attended = rename(abs(attended).mean(), "mean_attended")
    mean_bottom_output = rename(
        abs(bottom_output).mean(), "mean_bottom_output")
    weights_penalty = rename(monotonicity_penalty(weights, labels_mask),
                             "weights_penalty")
    weights_entropy = rename(entropy(weights, labels_mask), "weights_entropy")
    mask_density = rename(labels_mask.mean(), "mask_density")
    cg = ComputationGraph([
        cost, weights_penalty, weights_entropy, min_energy, max_energy,
        mean_attended, mean_bottom_output, batch_size, max_num_phonemes,
        mask_density
    ])
    # Regularization. It is applied explicitly to all variables
    # of interest, it could not be applied to the cost only as it
    # would not have effect on auxiliary variables, see Blocks #514.
    reg_config = config.get('regularization', dict())
    regularized_cg = cg
    if reg_config.get('dropout'):
        logger.info('apply dropout')
        regularized_cg = apply_dropout(cg, [bottom_output], 0.5)
    if reg_config.get('noise'):
        logger.info('apply noise')
        noise_subjects = [
            p for p in cg.parameters if p not in attention_params
        ]
        regularized_cg = apply_noise(cg, noise_subjects, reg_config['noise'])

    train_cost = regularized_cg.outputs[0]
    if reg_config.get("penalty_coof", .0) > 0:
        # big warning!!!
        # here we assume that:
        # regularized_weights_penalty = regularized_cg.outputs[1]
        train_cost = (train_cost + reg_config.get("penalty_coof", .0) *
                      regularized_cg.outputs[1] / batch_size)
    if reg_config.get("decay", .0) > 0:
        train_cost = (
            train_cost + reg_config.get("decay", .0) *
            l2_norm(VariableFilter(roles=[WEIGHT])(cg.parameters))**2)

    train_cost = rename(train_cost, 'train_cost')

    gradients = None
    if reg_config.get('adaptive_noise'):
        logger.info('apply adaptive noise')
        if ((reg_config.get("penalty_coof", .0) > 0)
                or (reg_config.get("decay", .0) > 0)):
            logger.error('using  adaptive noise with alignment weight panalty '
                         'or weight decay is probably stupid')
        train_cost, regularized_cg, gradients, noise_brick = apply_adaptive_noise(
            cg,
            cg.outputs[0],
            variables=cg.parameters,
            num_examples=data.get_dataset('train').num_examples,
            parameters=Model(
                regularized_cg.outputs[0]).get_parameter_dict().values(),
            **reg_config.get('adaptive_noise'))
        train_cost.name = 'train_cost'
        adapt_noise_cg = ComputationGraph(train_cost)
        model_prior_mean = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_prior_mean')(adapt_noise_cg)[0],
            'model_prior_mean')
        model_cost = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_cost')(adapt_noise_cg)[0], 'model_cost')
        model_prior_variance = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_prior_variance')(adapt_noise_cg)[0],
            'model_prior_variance')
        regularized_cg = ComputationGraph(
            [train_cost, model_cost] + regularized_cg.outputs +
            [model_prior_mean, model_prior_variance])
        primary_observables += [
            regularized_cg.outputs[1],  # model cost
            regularized_cg.outputs[2],  # task cost
            regularized_cg.outputs[-2],  # model prior mean
            regularized_cg.outputs[-1]
        ]  # model prior variance

    model = Model(train_cost)
    if params:
        logger.info("Load parameters from " + params)
        # please note: we cannot use recognizer.load_params
        # as it builds a new computation graph that dies not have
        # shapred variables added by adaptive weight noise
        with open(params, 'r') as src:
            param_values = load_parameters(src)
        model.set_parameter_values(param_values)

    parameters = model.get_parameter_dict()
    logger.info("Parameters:\n" +
                pprint.pformat([(key, parameters[key].get_value().shape)
                                for key in sorted(parameters.keys())],
                               width=120))

    # Define the training algorithm.
    clipping = StepClipping(train_conf['gradient_threshold'])
    clipping.threshold.name = "gradient_norm_threshold"
    rule_names = train_conf.get('rules', ['momentum'])
    core_rules = []
    if 'momentum' in rule_names:
        logger.info("Using scaling and momentum for training")
        core_rules.append(Momentum(train_conf['scale'],
                                   train_conf['momentum']))
    if 'adadelta' in rule_names:
        logger.info("Using AdaDelta for training")
        core_rules.append(
            AdaDelta(train_conf['decay_rate'], train_conf['epsilon']))
    max_norm_rules = []
    if reg_config.get('max_norm', False) > 0:
        logger.info("Apply MaxNorm")
        maxnorm_subjects = VariableFilter(roles=[WEIGHT])(cg.parameters)
        if reg_config.get('max_norm_exclude_lookup', False):
            maxnorm_subjects = [
                v for v in maxnorm_subjects
                if not isinstance(get_brick(v), LookupTable)
            ]
        logger.info("Parameters covered by MaxNorm:\n" + pprint.pformat(
            [name for name, p in parameters.items() if p in maxnorm_subjects]))
        logger.info("Parameters NOT covered by MaxNorm:\n" + pprint.pformat([
            name for name, p in parameters.items() if not p in maxnorm_subjects
        ]))
        max_norm_rules = [
            Restrict(VariableClipping(reg_config['max_norm'], axis=0),
                     maxnorm_subjects)
        ]
    burn_in = []
    if train_conf.get('burn_in_steps', 0):
        burn_in.append(BurnIn(num_steps=train_conf['burn_in_steps']))
    algorithm = GradientDescent(
        cost=train_cost,
        parameters=parameters.values(),
        gradients=gradients,
        step_rule=CompositeRule(
            [clipping] + core_rules + max_norm_rules +
            # Parameters are not changed at all
            # when nans are encountered.
            [RemoveNotFinite(0.0)] + burn_in),
        on_unused_sources='warn')

    logger.debug("Scan Ops in the gradients")
    gradient_cg = ComputationGraph(algorithm.gradients.values())
    for op in ComputationGraph(gradient_cg).scans:
        logger.debug(op)

    # More variables for debugging: some of them can be added only
    # after the `algorithm` object is created.
    secondary_observables += list(regularized_cg.outputs)
    if not 'train_cost' in [v.name for v in secondary_observables]:
        secondary_observables += [train_cost]
    secondary_observables += [
        algorithm.total_step_norm, algorithm.total_gradient_norm,
        clipping.threshold
    ]
    for name, param in parameters.items():
        num_elements = numpy.product(param.get_value().shape)
        norm = param.norm(2) / num_elements**0.5
        grad_norm = algorithm.gradients[param].norm(2) / num_elements**0.5
        step_norm = algorithm.steps[param].norm(2) / num_elements**0.5
        stats = tensor.stack(norm, grad_norm, step_norm, step_norm / grad_norm)
        stats.name = name + '_stats'
        secondary_observables.append(stats)

    primary_observables += [
        train_cost, algorithm.total_gradient_norm, algorithm.total_step_norm,
        clipping.threshold, max_recording_length, max_attended_length,
        max_attended_mask_length
    ]

    validation_observables += [
        rename(aggregation.mean(batch_cost, batch_size), cost.name),
        rename(aggregation.sum_(batch_size), 'num_utterances'),
        weights_entropy, weights_penalty
    ]

    def attach_aggregation_schemes(variables):
        # Aggregation specification has to be factored out as a separate
        # function as it has to be applied at the very last stage
        # separately to training and validation observables.
        result = []
        for var in variables:
            if var.name == 'weights_penalty':
                result.append(
                    rename(aggregation.mean(var, batch_size),
                           'weights_penalty_per_recording'))
            elif var.name == 'weights_entropy':
                result.append(
                    rename(aggregation.mean(var, labels_mask.sum()),
                           'weights_entropy_per_label'))
            else:
                result.append(var)
        return result

    mon_conf = config['monitoring']

    # Build main loop.
    logger.info("Initialize extensions")
    extensions = []
    if use_load_ext and params:
        extensions.append(
            Load(params, load_iteration_state=True, load_log=True))
    if load_log and params:
        extensions.append(LoadLog(params))
    extensions += [
        Timing(after_batch=True),
        CGStatistics(),
        #CodeVersion(['lvsr']),
    ]
    extensions.append(
        TrainingDataMonitoring(primary_observables + [l2_cost, cost_forward],
                               after_batch=True))
    average_monitoring = TrainingDataMonitoring(
        attach_aggregation_schemes(secondary_observables),
        prefix="average",
        every_n_batches=10)
    extensions.append(average_monitoring)
    validation = DataStreamMonitoring(
        attach_aggregation_schemes(validation_observables +
                                   [l2_cost, cost_forward]),
        data.get_stream("valid", shuffle=False),
        prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=mon_conf['validate_every_epochs'],
            every_n_batches=mon_conf['validate_every_batches'],
            after_training=False)
    extensions.append(validation)
    per = PhonemeErrorRate(recognizer, data, **config['monitoring']['search'])
    per_monitoring = DataStreamMonitoring(
        [per],
        data.get_stream("valid", batches=False, shuffle=False),
        prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=mon_conf['search_every_epochs'],
            every_n_batches=mon_conf['search_every_batches'],
            after_training=False)
    extensions.append(per_monitoring)
    track_the_best_per = TrackTheBest(
        per_monitoring.record_name(per)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    track_the_best_cost = TrackTheBest(
        validation.record_name(cost)).set_conditions(before_first_epoch=True,
                                                     after_epoch=True)
    extensions += [track_the_best_cost, track_the_best_per]
    extensions.append(
        AdaptiveClipping(algorithm.total_gradient_norm.name,
                         clipping,
                         train_conf['gradient_threshold'],
                         decay_rate=0.998,
                         burnin_period=500))
    extensions += [
        SwitchOffLengthFilter(
            data.length_filter,
            after_n_batches=train_conf.get('stop_filtering')),
        FinishAfter(after_n_batches=train_conf.get('num_batches'),
                    after_n_epochs=train_conf.get('num_epochs')).add_condition(
                        ["after_batch"], _gradient_norm_is_none),
    ]
    channels = [
        # Plot 1: training and validation costs
        [
            average_monitoring.record_name(train_cost),
            validation.record_name(cost)
        ],
        # Plot 2: gradient norm,
        [
            average_monitoring.record_name(algorithm.total_gradient_norm),
            average_monitoring.record_name(clipping.threshold)
        ],
        # Plot 3: phoneme error rate
        [per_monitoring.record_name(per)],
        # Plot 4: training and validation mean weight entropy
        [
            average_monitoring._record_name('weights_entropy_per_label'),
            validation._record_name('weights_entropy_per_label')
        ],
        # Plot 5: training and validation monotonicity penalty
        [
            average_monitoring._record_name('weights_penalty_per_recording'),
            validation._record_name('weights_penalty_per_recording')
        ]
    ]
    if bokeh:
        extensions += [
            Plot(bokeh_name if bokeh_name else os.path.basename(save_path),
                 channels,
                 every_n_batches=10,
                 server_url=bokeh_server),
        ]
    extensions += [
        Checkpoint(save_path,
                   before_first_epoch=not fast_start,
                   after_epoch=True,
                   every_n_batches=train_conf.get('save_every_n_batches'),
                   save_separately=["model", "log"],
                   use_cpickle=True).add_condition(
                       ['after_epoch'],
                       OnLogRecord(track_the_best_per.notification_name),
                       (root_path + "_best" + extension, )).add_condition(
                           ['after_epoch'],
                           OnLogRecord(track_the_best_cost.notification_name),
                           (root_path + "_best_ll" + extension, )),
        ProgressBar()
    ]
    extensions.append(EmbedIPython(use_main_loop_run_caller_env=True))
    if config['net']['criterion']['name'].startswith('mse'):
        extensions.append(
            LogInputsGains(labels, cg, recognizer.generator.readout.emitter,
                           data))

    if train_conf.get('patience'):
        patience_conf = train_conf['patience']
        if not patience_conf.get('notification_names'):
            # setdefault will not work for empty list
            patience_conf['notification_names'] = [
                track_the_best_per.notification_name,
                track_the_best_cost.notification_name
            ]
        extensions.append(Patience(**patience_conf))

    extensions.append(
        Printing(every_n_batches=1, attribute_filter=PrintingFilterList()))

    return model, algorithm, data, extensions
Exemple #3
0
def main(mode, save_path, num_batches, data_path=None):
    reverser = WordReverser(100, len(char2code), name="reverser")

    if mode == "train":
        # Data processing pipeline
        dataset_options = dict(dictionary=char2code, level="character",
                               preprocess=_lower)
        if data_path:
            dataset = TextFile(data_path, **dataset_options)
        else:
            dataset = OneBillionWord("training", [99], **dataset_options)
        data_stream = dataset.get_example_stream()
        data_stream = Filter(data_stream, _filter_long)
        data_stream = Mapping(data_stream, reverse_words,
                              add_sources=("targets",))
        data_stream = Batch(data_stream, iteration_scheme=ConstantScheme(10))
        data_stream = Padding(data_stream)
        data_stream = Mapping(data_stream, _transpose)

        # Initialization settings
        reverser.weights_init = IsotropicGaussian(0.1)
        reverser.biases_init = Constant(0.0)
        reverser.push_initialization_config()
        reverser.encoder.weghts_init = Orthogonal()
        reverser.generator.transition.weights_init = Orthogonal()

        # Build the cost computation graph
        chars = tensor.lmatrix("features")
        chars_mask = tensor.matrix("features_mask")
        targets = tensor.lmatrix("targets")
        targets_mask = tensor.matrix("targets_mask")
        batch_cost = reverser.cost(
            chars, chars_mask, targets, targets_mask).sum()
        batch_size = named_copy(chars.shape[1], "batch_size")
        cost = aggregation.mean(batch_cost,  batch_size)
        cost.name = "sequence_log_likelihood"
        logger.info("Cost graph is built")

        # Give an idea of what's going on
        model = Model(cost)
        params = model.get_params()
        logger.info("Parameters:\n" +
                    pprint.pformat(
                        [(key, value.get_value().shape) for key, value
                         in params.items()],
                        width=120))

        # Initialize parameters
        for brick in model.get_top_bricks():
            brick.initialize()

        # Define the training algorithm.
        cg = ComputationGraph(cost)
        algorithm = GradientDescent(
            cost=cost, params=cg.parameters,
            step_rule=CompositeRule([StepClipping(10.0), Scale(0.01)]))

        # Fetch variables useful for debugging
        generator = reverser.generator
        (energies,) = VariableFilter(
            application=generator.readout.readout,
            name="output")(cg.variables)
        (activations,) = VariableFilter(
            application=generator.transition.apply,
            name=generator.transition.apply.states[0])(cg.variables)
        max_length = named_copy(chars.shape[0], "max_length")
        cost_per_character = named_copy(
            aggregation.mean(batch_cost, batch_size * max_length),
            "character_log_likelihood")
        min_energy = named_copy(energies.min(), "min_energy")
        max_energy = named_copy(energies.max(), "max_energy")
        mean_activation = named_copy(abs(activations).mean(),
                                     "mean_activation")
        observables = [
            cost, min_energy, max_energy, mean_activation,
            batch_size, max_length, cost_per_character,
            algorithm.total_step_norm, algorithm.total_gradient_norm]
        for name, param in params.items():
            observables.append(named_copy(
                param.norm(2), name + "_norm"))
            observables.append(named_copy(
                algorithm.gradients[param].norm(2), name + "_grad_norm"))

        # Construct the main loop and start training!
        average_monitoring = TrainingDataMonitoring(
            observables, prefix="average", every_n_batches=10)
        main_loop = MainLoop(
            model=model,
            data_stream=data_stream,
            algorithm=algorithm,
            extensions=[
                Timing(),
                TrainingDataMonitoring(observables, after_batch=True),
                average_monitoring,
                FinishAfter(after_n_batches=num_batches)
                # This shows a way to handle NaN emerging during
                # training: simply finish it.
                .add_condition("after_batch", _is_nan),
                Plot(os.path.basename(save_path),
                     [[average_monitoring.record_name(cost)],
                      [average_monitoring.record_name(cost_per_character)]],
                     every_n_batches=10),
                # Saving the model and the log separately is convenient,
                # because loading the whole pickle takes quite some time.
                Checkpoint(save_path, every_n_batches=500,
                           save_separately=["model", "log"]),
                Printing(every_n_batches=1)])
        main_loop.run()
    elif mode == "sample" or mode == "beam_search":
        chars = tensor.lmatrix("input")
        generated = reverser.generate(chars)
        model = Model(generated)
        logger.info("Loading the model..")
        model.set_param_values(load_parameter_values(save_path))

        def generate(input_):
            """Generate output sequences for an input sequence.

            Incapsulates most of the difference between sampling and beam
            search.

            Returns
            -------
            outputs : list of lists
                Trimmed output sequences.
            costs : list
                The negative log-likelihood of generating the respective
                sequences.

            """
            if mode == "beam_search":
                samples, = VariableFilter(
                    bricks=[reverser.generator], name="outputs")(
                        ComputationGraph(generated[1]))
                # NOTE: this will recompile beam search functions
                # every time user presses Enter. Do not create
                # a new `BeamSearch` object every time if
                # speed is important for you.
                beam_search = BeamSearch(input_.shape[1], samples)
                outputs, costs = beam_search.search(
                    {chars: input_}, char2code['</S>'],
                    3 * input_.shape[0])
            else:
                _1, outputs, _2, _3, costs = (
                    model.get_theano_function()(input_))
                outputs = list(outputs.T)
                costs = list(costs.T)
                for i in range(len(outputs)):
                    outputs[i] = list(outputs[i])
                    try:
                        true_length = outputs[i].index(char2code['</S>']) + 1
                    except ValueError:
                        true_length = len(outputs[i])
                    outputs[i] = outputs[i][:true_length]
                    costs[i] = costs[i][:true_length].sum()
            return outputs, costs

        while True:
            line = input("Enter a sentence\n")
            message = ("Enter the number of samples\n" if mode == "sample"
                       else "Enter the beam size\n")
            batch_size = int(input(message))

            encoded_input = [char2code.get(char, char2code["<UNK>"])
                             for char in line.lower().strip()]
            encoded_input = ([char2code['<S>']] + encoded_input +
                             [char2code['</S>']])
            print("Encoder input:", encoded_input)
            target = reverse_words((encoded_input,))[0]
            print("Target: ", target)

            samples, costs = generate(
                numpy.repeat(numpy.array(encoded_input)[:, None],
                             batch_size, axis=1))
            messages = []
            for sample, cost in equizip(samples, costs):
                message = "({})".format(cost)
                message += "".join(code2char[code] for code in sample)
                if sample == target:
                    message += " CORRECT!"
                messages.append((cost, message))
            messages.sort(key=operator.itemgetter(0), reverse=True)
            for _, message in messages:
                print(message)
              StepClipping(step_clipping)]
algorithm = GradientDescent(cost=cost, parameters=cg.parameters,
                            step_rule=CompositeRule(step_rules))

# Extensions
gradient_norm = aggregation.mean(algorithm.total_gradient_norm)
step_norm = aggregation.mean(algorithm.total_step_norm)
monitored_vars = [cost, gradient_norm, step_norm]

dev_monitor = DataStreamMonitoring(variables=[cost], after_batch=True,
                                   before_first_epoch=True, data_stream=dev_stream, prefix="dev")
train_monitor = TrainingDataMonitoring(variables=monitored_vars, after_batch=True,
                                       before_first_epoch=True, prefix='train')

plotter = Plot('RNN char-level prediction',
	       channels=[[train_monitor.record_name(cost)],
                  [dev_monitor.record_name(cost)]],
	       server_url="http://bart4.iro.umontreal.ca:5006",
	       after_batch=True)


if start_from_checkpoint == True:
    extensions = [dev_monitor, train_monitor, Timing(), Printing(after_batch=True),
                FinishAfter(after_n_epochs=num_epochs),
                saveload.Load(last_path, load_log=True), plotter,
                saveload.Checkpoint(last_path, save_separately=['log']),
                ] + track_best('dev_cost', save_path)
else: #start fresh
    extensions = [dev_monitor, train_monitor, Timing(), Printing(after_batch=True),
                FinishAfter(after_n_epochs=num_epochs),
                saveload.Load(load_path), plotter,
Exemple #5
0
def train(config, save_path, bokeh_name,
          params, bokeh_server, test_tag, use_load_ext,
          load_log, fast_start, validation_epochs, validation_batches,
          per_epochs, per_batches):
    root_path, extension = os.path.splitext(save_path)

    data = Data(**config['data'])

    # Build the main brick and initialize all parameters.
    recognizer = SpeechRecognizer(
        data.recordings_source, data.labels_source,
        data.eos_label,
        data.num_features, data.num_labels,
        name="recognizer",
        data_prepend_eos=data.prepend_eos,
        character_map=data.character_map,
        **config["net"])
    for brick_path, attribute_dict in sorted(
            config['initialization'].items(),
            key=lambda (k, v): -k.count('/')):
        for attribute, value in attribute_dict.items():
            brick, = Selector(recognizer).select(brick_path).bricks
            setattr(brick, attribute, value)
            brick.push_initialization_config()
    recognizer.initialize()

    # Separate attention_params to be handled differently
    # when regularization is applied
    attention = recognizer.generator.transition.attention
    attention_params = Selector(attention).get_parameters().values()

    logger.info(
        "Initialization schemes for all bricks.\n"
        "Works well only in my branch with __repr__ added to all them,\n"
        "there is an issue #463 in Blocks to do that properly.")

    def show_init_scheme(cur):
        result = dict()
        for attr in dir(cur):
            if attr.endswith('_init'):
                result[attr] = getattr(cur, attr)
        for child in cur.children:
            result[child.name] = show_init_scheme(child)
        return result
    logger.info(pprint.pformat(show_init_scheme(recognizer)))

    if params:
        logger.info("Load parameters from " + params)
        recognizer.load_params(params)

    if test_tag:
        tensor.TensorVariable.__str__ = tensor.TensorVariable.__repr__
        __stream = data.get_stream("train")
        __data = next(__stream.get_epoch_iterator(as_dict=True))
        recognizer.recordings.tag.test_value = __data[data.recordings_source]
        recognizer.recordings_mask.tag.test_value = __data[data.recordings_source + '_mask']
        recognizer.labels.tag.test_value = __data[data.labels_source]
        recognizer.labels_mask.tag.test_value = __data[data.labels_source + '_mask']
        theano.config.compute_test_value = 'warn'

    batch_cost = recognizer.get_cost_graph().sum()
    batch_size = named_copy(recognizer.recordings.shape[1], "batch_size")
    # Assumes constant batch size. `aggregation.mean` is not used because
    # of Blocks #514.
    cost = batch_cost / batch_size
    cost.name = "sequence_log_likelihood"
    logger.info("Cost graph is built")

    # Fetch variables useful for debugging.
    # It is important not to use any aggregation schemes here,
    # as it's currently impossible to spread the effect of
    # regularization on their variables, see Blocks #514.
    cost_cg = ComputationGraph(cost)
    r = recognizer
    energies, = VariableFilter(
        applications=[r.generator.readout.readout], name="output_0")(
                cost_cg)
    bottom_output, = VariableFilter(
        applications=[r.bottom.apply], name="output")(
                cost_cg)
    attended, = VariableFilter(
        applications=[r.generator.transition.apply], name="attended")(
                cost_cg)
    attended_mask, = VariableFilter(
        applications=[r.generator.transition.apply], name="attended_mask")(
                cost_cg)
    weights, = VariableFilter(
        applications=[r.generator.evaluate], name="weights")(
                cost_cg)
    max_recording_length = named_copy(r.recordings.shape[0],
                                      "max_recording_length")
    # To exclude subsampling related bugs
    max_attended_mask_length = named_copy(attended_mask.shape[0],
                                          "max_attended_mask_length")
    max_attended_length = named_copy(attended.shape[0],
                                     "max_attended_length")
    max_num_phonemes = named_copy(r.labels.shape[0],
                                  "max_num_phonemes")
    min_energy = named_copy(energies.min(), "min_energy")
    max_energy = named_copy(energies.max(), "max_energy")
    mean_attended = named_copy(abs(attended).mean(),
                               "mean_attended")
    mean_bottom_output = named_copy(abs(bottom_output).mean(),
                                    "mean_bottom_output")
    weights_penalty = named_copy(monotonicity_penalty(weights, r.labels_mask),
                                 "weights_penalty")
    weights_entropy = named_copy(entropy(weights, r.labels_mask),
                                 "weights_entropy")
    mask_density = named_copy(r.labels_mask.mean(),
                              "mask_density")
    cg = ComputationGraph([
        cost, weights_penalty, weights_entropy,
        min_energy, max_energy,
        mean_attended, mean_bottom_output,
        batch_size, max_num_phonemes,
        mask_density])

    # Regularization. It is applied explicitly to all variables
    # of interest, it could not be applied to the cost only as it
    # would not have effect on auxiliary variables, see Blocks #514.
    reg_config = config['regularization']
    regularized_cg = cg
    if reg_config.get('dropout'):
        logger.info('apply dropout')
        regularized_cg = apply_dropout(cg, [bottom_output], 0.5)
    if reg_config.get('noise'):
        logger.info('apply noise')
        noise_subjects = [p for p in cg.parameters if p not in attention_params]
        regularized_cg = apply_noise(cg, noise_subjects, reg_config['noise'])
    regularized_cost = regularized_cg.outputs[0]
    regularized_weights_penalty = regularized_cg.outputs[1]

    # Model is weird class, we spend lots of time arguing with Bart
    # what it should be. However it can already nice things, e.g.
    # one extract all the parameters from the computation graphs
    # and give them hierahical names. This help to notice when a
    # because of some bug a parameter is not in the computation
    # graph.
    model = SpeechModel(regularized_cost)
    params = model.get_parameter_dict()
    logger.info("Parameters:\n" +
                pprint.pformat(
                    [(key, params[key].get_value().shape) for key
                        in sorted(params.keys())],
                    width=120))

    # Define the training algorithm.
    train_conf = config['training']
    clipping = StepClipping(train_conf['gradient_threshold'])
    clipping.threshold.name = "gradient_norm_threshold"
    rule_names = train_conf.get('rules', ['momentum'])
    core_rules = []
    if 'momentum' in rule_names:
        logger.info("Using scaling and momentum for training")
        core_rules.append(Momentum(train_conf['scale'], train_conf['momentum']))
    if 'adadelta' in rule_names:
        logger.info("Using AdaDelta for training")
        core_rules.append(AdaDelta(train_conf['decay_rate'], train_conf['epsilon']))
    max_norm_rules = []
    if reg_config.get('max_norm', False):
        logger.info("Apply MaxNorm")
        maxnorm_subjects = VariableFilter(roles=[WEIGHT])(cg.parameters)
        if reg_config.get('max_norm_exclude_lookup', False):
            maxnorm_subjects = [v for v in maxnorm_subjects
                                if not isinstance(get_brick(v), LookupTable)]
        logger.info("Parameters covered by MaxNorm:\n"
                    + pprint.pformat([name for name, p in params.items()
                                        if p in maxnorm_subjects]))
        logger.info("Parameters NOT covered by MaxNorm:\n"
                    + pprint.pformat([name for name, p in params.items()
                                        if not p in maxnorm_subjects]))
        max_norm_rules = [
            Restrict(VariableClipping(reg_config['max_norm'], axis=0),
                        maxnorm_subjects)]
    algorithm = GradientDescent(
        cost=regularized_cost +
            reg_config.get("penalty_coof", .0) * regularized_weights_penalty / batch_size +
            reg_config.get("decay", .0) *
            l2_norm(VariableFilter(roles=[WEIGHT])(cg.parameters)) ** 2,
        parameters=params.values(),
        step_rule=CompositeRule(
            [clipping] + core_rules + max_norm_rules +
            # Parameters are not changed at all
            # when nans are encountered.
            [RemoveNotFinite(0.0)]))

    # More variables for debugging: some of them can be added only
    # after the `algorithm` object is created.
    observables = regularized_cg.outputs
    observables += [
        algorithm.total_step_norm, algorithm.total_gradient_norm,
        clipping.threshold]
    for name, param in params.items():
        num_elements = numpy.product(param.get_value().shape)
        norm = param.norm(2) / num_elements ** 0.5
        grad_norm = algorithm.gradients[param].norm(2) / num_elements ** 0.5
        step_norm = algorithm.steps[param].norm(2) / num_elements ** 0.5
        stats = tensor.stack(norm, grad_norm, step_norm, step_norm / grad_norm)
        stats.name = name + '_stats'
        observables.append(stats)

    def attach_aggregation_schemes(variables):
        # Aggregation specification has to be factored out as a separate
        # function as it has to be applied at the very last stage
        # separately to training and validation observables.
        result = []
        for var in variables:
            if var.name == 'weights_penalty':
                result.append(named_copy(aggregation.mean(var, batch_size),
                                            'weights_penalty_per_recording'))
            elif var.name == 'weights_entropy':
                result.append(named_copy(aggregation.mean(
                    var, recognizer.labels_mask.sum()), 'weights_entropy_per_label'))
            else:
                result.append(var)
        return result

    # Build main loop.
    logger.info("Initialize extensions")
    extensions = []
    if use_load_ext and params:
        extensions.append(Load(params, load_iteration_state=True, load_log=True))
    if load_log and params:
        extensions.append(LoadLog(params))
    extensions += [
        Timing(after_batch=True),
        CGStatistics(),
        #CodeVersion(['lvsr']),
        ]
    extensions.append(TrainingDataMonitoring(
        [observables[0], algorithm.total_gradient_norm,
            algorithm.total_step_norm, clipping.threshold,
            max_recording_length,
            max_attended_length, max_attended_mask_length], after_batch=True))
    average_monitoring = TrainingDataMonitoring(
        attach_aggregation_schemes(observables),
        prefix="average", every_n_batches=10)
    extensions.append(average_monitoring)
    validation = DataStreamMonitoring(
        attach_aggregation_schemes([cost, weights_entropy, weights_penalty]),
        data.get_stream("valid"), prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=validation_epochs,
            every_n_batches=validation_batches,
            after_training=False)
    extensions.append(validation)
    recognizer.init_beam_search(10)
    per = PhonemeErrorRate(recognizer, data.get_dataset("valid"))
    per_monitoring = DataStreamMonitoring(
        [per], data.get_stream("valid", batches=False, shuffle=False),
        prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=per_epochs,
            every_n_batches=per_batches,
            after_training=False)
    extensions.append(per_monitoring)
    track_the_best_per = TrackTheBest(
        per_monitoring.record_name(per)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    track_the_best_likelihood = TrackTheBest(
        validation.record_name(cost)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    extensions += [track_the_best_likelihood, track_the_best_per]
    extensions.append(AdaptiveClipping(
        algorithm.total_gradient_norm.name,
        clipping, train_conf['gradient_threshold'],
        decay_rate=0.998, burnin_period=500))
    extensions += [
        SwitchOffLengthFilter(data.length_filter,
            after_n_batches=train_conf.get('stop_filtering')),
        FinishAfter(after_n_batches=train_conf['num_batches'],
                    after_n_epochs=train_conf['num_epochs'])
        .add_condition(["after_batch"], _gradient_norm_is_none),
        # Live plotting: requires launching `bokeh-server`
        # and allows to see what happens online.
        Plot(bokeh_name
             if bokeh_name
             else os.path.basename(save_path),
             [# Plot 1: training and validation costs
             [average_monitoring.record_name(regularized_cost),
             validation.record_name(cost)],
             # Plot 2: gradient norm,
             [average_monitoring.record_name(algorithm.total_gradient_norm),
             average_monitoring.record_name(clipping.threshold)],
             # Plot 3: phoneme error rate
             [per_monitoring.record_name(per)],
             # Plot 4: training and validation mean weight entropy
             [average_monitoring._record_name('weights_entropy_per_label'),
             validation._record_name('weights_entropy_per_label')],
             # Plot 5: training and validation monotonicity penalty
             [average_monitoring._record_name('weights_penalty_per_recording'),
             validation._record_name('weights_penalty_per_recording')]],
             every_n_batches=10,
             server_url=bokeh_server),
        Checkpoint(save_path,
                   before_first_epoch=not fast_start, after_epoch=True,
                   every_n_batches=train_conf.get('save_every_n_batches'),
                   save_separately=["model", "log"],
                   use_cpickle=True)
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_per.notification_name),
            (root_path + "_best" + extension,))
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_likelihood.notification_name),
            (root_path + "_best_ll" + extension,)),
        ProgressBar(),
        Printing(every_n_batches=1,
                    attribute_filter=PrintingFilterList()
                    )]

    # Save the config into the status
    log = TrainingLog()
    log.status['_config'] = repr(config)
    main_loop = MainLoop(
        model=model, log=log, algorithm=algorithm,
        data_stream=data.get_stream("train"),
        extensions=extensions)
    main_loop.run()
Exemple #6
0
def main(mode, save_path, num_batches, data_path=None):
    reverser = WordReverser(100, len(char2code), name="reverser")

    if mode == "train":
        # Data processing pipeline
        dataset_options = dict(dictionary=char2code, level="character",
                               preprocess=_lower)
        if data_path:
            dataset = TextFile(data_path, **dataset_options)
        else:
            dataset = OneBillionWord("training", [99], **dataset_options)
        data_stream = dataset.get_example_stream()
        data_stream = Filter(data_stream, _filter_long)
        data_stream = Mapping(data_stream, reverse_words,
                              add_sources=("targets",))
        data_stream = Batch(data_stream, iteration_scheme=ConstantScheme(10))
        data_stream = Padding(data_stream)
        data_stream = Mapping(data_stream, _transpose)

        # Initialization settings
        reverser.weights_init = IsotropicGaussian(0.1)
        reverser.biases_init = Constant(0.0)
        reverser.push_initialization_config()
        reverser.encoder.weights_init = Orthogonal()
        reverser.generator.transition.weights_init = Orthogonal()

        # Build the cost computation graph
        chars = tensor.lmatrix("features")
        chars_mask = tensor.matrix("features_mask")
        targets = tensor.lmatrix("targets")
        targets_mask = tensor.matrix("targets_mask")
        batch_cost = reverser.cost(
            chars, chars_mask, targets, targets_mask).sum()
        batch_size = named_copy(chars.shape[1], "batch_size")
        cost = aggregation.mean(batch_cost,  batch_size)
        cost.name = "sequence_log_likelihood"
        logger.info("Cost graph is built")

        # Give an idea of what's going on
        model = Model(cost)
        params = model.get_params()
        logger.info("Parameters:\n" +
                    pprint.pformat(
                        [(key, value.get_value().shape) for key, value
                         in params.items()],
                        width=120))

        # Initialize parameters
        for brick in model.get_top_bricks():
            brick.initialize()

        # Define the training algorithm.
        cg = ComputationGraph(cost)
        algorithm = GradientDescent(
            cost=cost, params=cg.parameters,
            step_rule=CompositeRule([StepClipping(10.0), Scale(0.01)]))

        # Fetch variables useful for debugging
        generator = reverser.generator
        (energies,) = VariableFilter(
            applications=[generator.readout.readout],
            name_regex="output")(cg.variables)
        (activations,) = VariableFilter(
            applications=[generator.transition.apply],
            name=generator.transition.apply.states[0])(cg.variables)
        max_length = named_copy(chars.shape[0], "max_length")
        cost_per_character = named_copy(
            aggregation.mean(batch_cost, batch_size * max_length),
            "character_log_likelihood")
        min_energy = named_copy(energies.min(), "min_energy")
        max_energy = named_copy(energies.max(), "max_energy")
        mean_activation = named_copy(abs(activations).mean(),
                                     "mean_activation")
        observables = [
            cost, min_energy, max_energy, mean_activation,
            batch_size, max_length, cost_per_character,
            algorithm.total_step_norm, algorithm.total_gradient_norm]
        for name, param in params.items():
            observables.append(named_copy(
                param.norm(2), name + "_norm"))
            observables.append(named_copy(
                algorithm.gradients[param].norm(2), name + "_grad_norm"))

        # Construct the main loop and start training!
        average_monitoring = TrainingDataMonitoring(
            observables, prefix="average", every_n_batches=10)
        main_loop = MainLoop(
            model=model,
            data_stream=data_stream,
            algorithm=algorithm,
            extensions=[
                Timing(),
                TrainingDataMonitoring(observables, after_batch=True),
                average_monitoring,
                FinishAfter(after_n_batches=num_batches)
                # This shows a way to handle NaN emerging during
                # training: simply finish it.
                .add_condition("after_batch", _is_nan),
                Plot(os.path.basename(save_path),
                     [[average_monitoring.record_name(cost)],
                      [average_monitoring.record_name(cost_per_character)]],
                     every_n_batches=10),
                # Saving the model and the log separately is convenient,
                # because loading the whole pickle takes quite some time.
                Checkpoint(save_path, every_n_batches=500,
                           save_separately=["model", "log"]),
                Printing(every_n_batches=1)])
        main_loop.run()
    elif mode == "sample" or mode == "beam_search":
        chars = tensor.lmatrix("input")
        generated = reverser.generate(chars)
        model = Model(generated)
        logger.info("Loading the model..")
        model.set_param_values(load_parameter_values(save_path))

        def generate(input_):
            """Generate output sequences for an input sequence.

            Incapsulates most of the difference between sampling and beam
            search.

            Returns
            -------
            outputs : list of lists
                Trimmed output sequences.
            costs : list
                The negative log-likelihood of generating the respective
                sequences.

            """
            if mode == "beam_search":
                samples, = VariableFilter(
                    bricks=[reverser.generator], name="outputs")(
                        ComputationGraph(generated[1]))
                # NOTE: this will recompile beam search functions
                # every time user presses Enter. Do not create
                # a new `BeamSearch` object every time if
                # speed is important for you.
                beam_search = BeamSearch(input_.shape[1], samples)
                outputs, costs = beam_search.search(
                    {chars: input_}, char2code['</S>'],
                    3 * input_.shape[0])
            else:
                _1, outputs, _2, _3, costs = (
                    model.get_theano_function()(input_))
                outputs = list(outputs.T)
                costs = list(costs.T)
                for i in range(len(outputs)):
                    outputs[i] = list(outputs[i])
                    try:
                        true_length = outputs[i].index(char2code['</S>']) + 1
                    except ValueError:
                        true_length = len(outputs[i])
                    outputs[i] = outputs[i][:true_length]
                    costs[i] = costs[i][:true_length].sum()
            return outputs, costs

        while True:
            line = input("Enter a sentence\n")
            message = ("Enter the number of samples\n" if mode == "sample"
                       else "Enter the beam size\n")
            batch_size = int(input(message))

            encoded_input = [char2code.get(char, char2code["<UNK>"])
                             for char in line.lower().strip()]
            encoded_input = ([char2code['<S>']] + encoded_input +
                             [char2code['</S>']])
            print("Encoder input:", encoded_input)
            target = reverse_words((encoded_input,))[0]
            print("Target: ", target)

            samples, costs = generate(
                numpy.repeat(numpy.array(encoded_input)[:, None],
                             batch_size, axis=1))
            messages = []
            for sample, cost in equizip(samples, costs):
                message = "({})".format(cost)
                message += "".join(code2char[code] for code in sample)
                if sample == target:
                    message += " CORRECT!"
                messages.append((cost, message))
            messages.sort(key=operator.itemgetter(0), reverse=True)
            for _, message in messages:
                print(message)
def main(mode, save_path, steps, num_batches, load_params):
    chars = (list(string.ascii_uppercase) + list(range(10)) +
             [' ', '.', ',', '\'', '"', '!', '?', '<UNK>'])
    char_to_ind = {char: i for i, char in enumerate(chars)}
    ind_to_char = {v: k for k, v in char_to_ind.iteritems()}

    train_dataset = TextFile(['/Tmp/serdyuk/data/wsj_text_train'],
                             char_to_ind, bos_token=None, eos_token=None,
                             level='character')
    valid_dataset = TextFile(['/Tmp/serdyuk/data/wsj_text_valid'],
                             char_to_ind, bos_token=None, eos_token=None,
                             level='character')

    vocab_size = len(char_to_ind)
    logger.info('Dictionary size: {}'.format(vocab_size))
    if mode == 'continue':
        continue_training(save_path)
        return
    elif mode == "sample":
        main_loop = load(open(save_path, "rb"))
        generator = main_loop.model.get_top_bricks()[-1]

        sample = ComputationGraph(generator.generate(
            n_steps=steps, batch_size=1, iterate=True)).get_theano_function()

        states, outputs, costs = [data[:, 0] for data in sample()]
        print("".join([ind_to_char[s] for s in outputs]))

        numpy.set_printoptions(precision=3, suppress=True)
        print("Generation cost:\n{}".format(costs.sum()))

        freqs = numpy.bincount(outputs).astype(floatX)
        freqs /= freqs.sum()

        trans_freqs = numpy.zeros((vocab_size, vocab_size), dtype=floatX)
        for a, b in zip(outputs, outputs[1:]):
            trans_freqs[a, b] += 1
        trans_freqs /= trans_freqs.sum(axis=1)[:, None]
        return

    # Experiment configuration
    batch_size = 20
    dim = 650
    feedback_dim = 650

    valid_stream = valid_dataset.get_example_stream()
    valid_stream = Batch(valid_stream,
                         iteration_scheme=ConstantScheme(batch_size))
    valid_stream = Padding(valid_stream)
    valid_stream = Mapping(valid_stream, _transpose)

    # Build the bricks and initialize them

    transition = GatedRecurrent(name="transition", dim=dim,
                                activation=Tanh())
    generator = SequenceGenerator(
        Readout(readout_dim=vocab_size, source_names=transition.apply.states,
                emitter=SoftmaxEmitter(name="emitter"),
                feedback_brick=LookupFeedback(
                    vocab_size, feedback_dim, name='feedback'),
                name="readout"),
        transition,
        weights_init=Uniform(std=0.04), biases_init=Constant(0),
        name="generator")
    generator.push_initialization_config()
    transition.weights_init = Orthogonal()
    transition.push_initialization_config()
    generator.initialize()

    # Build the cost computation graph.
    features = tensor.lmatrix('features')
    features_mask = tensor.matrix('features_mask')
    cost_matrix = generator.cost_matrix(
        features, mask=features_mask)
    batch_cost = cost_matrix.sum()
    cost = aggregation.mean(
        batch_cost,
        features.shape[1])
    cost.name = "sequence_log_likelihood"
    char_cost = aggregation.mean(
        batch_cost, features_mask.sum())
    char_cost.name = 'character_log_likelihood'
    ppl = 2 ** (cost / numpy.log(2))
    ppl.name = 'ppl'
    bits_per_char = char_cost / tensor.log(2)
    bits_per_char.name = 'bits_per_char'
    length = features.shape[0]
    length.name = 'length'

    model = Model(batch_cost)
    if load_params:
        params = load_parameter_values(save_path)
        model.set_parameter_values(params)

    if mode == "train":
        # Give an idea of what's going on.
        logger.info("Parameters:\n" +
                    pprint.pformat(
                        [(key, value.get_value().shape) for key, value
                         in Selector(generator).get_parameters().items()],
                        width=120))

        train_stream = train_dataset.get_example_stream()
        train_stream = Mapping(train_stream, _truncate)
        train_stream = Batch(train_stream,
                             iteration_scheme=ConstantScheme(batch_size))
        train_stream = Padding(train_stream)
        train_stream = Mapping(train_stream, _transpose)

        parameters = model.get_parameter_dict()
        maxnorm_subjects = VariableFilter(roles=[WEIGHT])(parameters.values())
        algorithm = GradientDescent(
            cost=batch_cost,
            parameters=parameters.values(),
            step_rule=CompositeRule([StepClipping(1000.), 
                AdaDelta(epsilon=1e-8) #, Restrict(VariableClipping(1.0, axis=0), maxnorm_subjects)
                                     ]))
        ft = features[:6, 0]
        ft.name = 'feature_example'

        observables = [cost, ppl, char_cost, length, bits_per_char]
        for name, param in parameters.items():
            num_elements = numpy.product(param.get_value().shape)
            norm = param.norm(2) / num_elements ** 0.5
            grad_norm = algorithm.gradients[param].norm(2) / num_elements ** 0.5
            step_norm = algorithm.steps[param].norm(2) / num_elements ** 0.5
            stats = tensor.stack(norm, grad_norm, step_norm, step_norm / grad_norm)
            stats.name = name + '_stats'
            observables.append(stats)
        track_the_best_bpc = TrackTheBest('valid_bits_per_char')
        root_path, extension = os.path.splitext(save_path)

        this_step_monitoring = TrainingDataMonitoring(
            observables + [ft], prefix="this_step", after_batch=True)
        average_monitoring = TrainingDataMonitoring(
            observables + [algorithm.total_step_norm,
                           algorithm.total_gradient_norm], 
            prefix="average",
            every_n_batches=10)
        valid_monitoring = DataStreamMonitoring(
            observables, prefix="valid",
            every_n_batches=1500, before_training=False,
            data_stream=valid_stream)
        main_loop = MainLoop(
            algorithm=algorithm,
            data_stream=train_stream,
            model=model,
            extensions=[
                this_step_monitoring,
                average_monitoring,
                valid_monitoring,
                track_the_best_bpc,
                Checkpoint(save_path, ),
                Checkpoint(save_path,
                           every_n_batches=500,
                           save_separately=["model", "log"],
                           use_cpickle=True)
                    .add_condition(
                    ['after_epoch'],
                    OnLogRecord(track_the_best_bpc.notification_name),
                    (root_path + "_best" + extension,)),
                Timing(after_batch=True),
                Printing(every_n_batches=10),
                Plot(root_path,
                     [[average_monitoring.record_name(cost),
                       valid_monitoring.record_name(cost)],
                      [average_monitoring.record_name(algorithm.total_step_norm)],
                      [average_monitoring.record_name(algorithm.total_gradient_norm)],
                      [average_monitoring.record_name(ppl),
                       valid_monitoring.record_name(ppl)],
                      [average_monitoring.record_name(char_cost),
                       valid_monitoring.record_name(char_cost)],
                      [average_monitoring.record_name(bits_per_char),
                       valid_monitoring.record_name(bits_per_char)]],
                     every_n_batches=10)
            ])
        main_loop.run()

    elif mode == 'evaluate':
        with open('/data/lisatmp3/serdyuk/wsj_lms/lms/wsj_trigram_with_initial_eos/lexicon.txt') as f:
            raw_words = [line.split()[1:-1] for line in f.readlines()]
            words = [[char_to_ind[c] if c in char_to_ind else char_to_ind['<UNK>'] for c in w] 
                     for w in raw_words]
        max_word_length = max([len(w) for w in words])
        
        initial_states = tensor.matrix('init_states')
        cost_matrix_step = generator.cost_matrix(features, mask=features_mask,
                                                 states=initial_states)
        cg = ComputationGraph(cost_matrix_step)
        states = cg.auxiliary_variables[-2]
        compute_cost = theano.function([features, features_mask, initial_states], 
                                       [cost_matrix_step.sum(axis=0), states])

        cost_matrix = generator.cost_matrix(features, mask=features_mask)
        initial_cg = ComputationGraph(cost_matrix)
        initial_states = initial_cg.auxiliary_variables[-2]

        total_word_cost = 0
        num_words = 0
        examples = numpy.zeros((max_word_length + 1, len(words)),
                               dtype='int64')
        all_masks = numpy.zeros((max_word_length + 1, len(words)),
                                dtype=floatX)

        for i, word in enumerate(words):
            examples[:len(word), i] = word
            all_masks[:len(word), i] = 1.

        single_space = numpy.array([char_to_ind[' ']])[:, None]

        for batch in valid_stream.get_epoch_iterator():
            for example, mask in equizip(batch[0].T, batch[1].T):
                example = example[:(mask.sum())]
                spc_inds = list(numpy.where(example == char_to_ind[" "])[0])
                state = generator.transition.transition.initial_states_.get_value()[None, :]
                for i, j in equizip([-1] + spc_inds, spc_inds + [-1]):
                    word = example[(i+1):j, None]
                    word_cost, states = compute_cost(
                        word, numpy.ones_like(word, dtype=floatX), state)
                    state = states[-1]

                    costs = numpy.exp(-compute_cost(
                        examples, all_masks, numpy.tile(state, [examples.shape[1], 1]))[0])

                    _, space_states = compute_cost(
                        single_space, numpy.ones_like(single_space, dtype=floatX), state)
                    state = space_states[-1]

                    word_prob = numpy.exp(-word_cost)
                    total_word_cost += word_cost + numpy.log(numpy.sum(costs))
                    num_words += 1
                    print(word_prob)
                    print(numpy.sum(costs))
                    print("Average cost", total_word_cost / num_words)
                    print("PPL", numpy.exp(total_word_cost / num_words))

        print("Word-level perplexity")
        print(total_word_cost / num_words)
    else:
        assert False
Exemple #8
0
def main(mode, save_path, num_batches, data_path=None):
    # Experiment configuration
    dimension = 100
    readout_dimension = len(char2code)

    # Build bricks
    encoder = Bidirectional(SimpleRecurrent(dim=dimension, activation=Tanh()),
                            weights_init=Orthogonal())
    fork = Fork(
        [name for name in encoder.prototype.apply.sequences if name != 'mask'],
        weights_init=IsotropicGaussian(0.1),
        biases_init=Constant(0))
    fork.input_dim = dimension
    fork.output_dims = {name: dimension for name in fork.input_names}
    lookup = LookupTable(readout_dimension,
                         dimension,
                         weights_init=IsotropicGaussian(0.1))
    transition = SimpleRecurrent(activation=Tanh(),
                                 dim=dimension,
                                 name="transition")
    attention = SequenceContentAttention(state_names=transition.apply.states,
                                         sequence_dim=2 * dimension,
                                         match_dim=dimension,
                                         name="attention")
    readout = LinearReadout(readout_dim=readout_dimension,
                            source_names=["states"],
                            emitter=SoftmaxEmitter(name="emitter"),
                            feedbacker=LookupFeedback(readout_dimension,
                                                      dimension),
                            name="readout")
    generator = SequenceGenerator(readout=readout,
                                  transition=transition,
                                  attention=attention,
                                  weights_init=IsotropicGaussian(0.1),
                                  biases_init=Constant(0),
                                  name="generator")
    generator.push_initialization_config()
    transition.weights_init = Orthogonal()

    if mode == "train":
        # Data processing pipeline
        dataset_options = dict(dictionary=char2code,
                               level="character",
                               preprocess=_lower)
        if data_path:
            dataset = TextFile(data_path, **dataset_options)
        else:
            dataset = OneBillionWord("training", [99], **dataset_options)
        data_stream = DataStreamMapping(
            mapping=_transpose,
            data_stream=PaddingDataStream(
                BatchDataStream(
                    iteration_scheme=ConstantScheme(10),
                    data_stream=DataStreamMapping(
                        mapping=reverse_words,
                        add_sources=("targets", ),
                        data_stream=DataStreamFilter(
                            predicate=_filter_long,
                            data_stream=dataset.get_default_stream())))))

        # Build the cost computation graph
        chars = tensor.lmatrix("features")
        chars_mask = tensor.matrix("features_mask")
        targets = tensor.lmatrix("targets")
        targets_mask = tensor.matrix("targets_mask")
        batch_cost = generator.cost(
            targets,
            targets_mask,
            attended=encoder.apply(**dict_union(fork.apply(
                lookup.lookup(chars), return_dict=True),
                                                mask=chars_mask)),
            attended_mask=chars_mask).sum()
        batch_size = named_copy(chars.shape[1], "batch_size")
        cost = aggregation.mean(batch_cost, batch_size)
        cost.name = "sequence_log_likelihood"
        logger.info("Cost graph is built")

        # Give an idea of what's going on
        model = Model(cost)
        params = model.get_params()
        logger.info("Parameters:\n" +
                    pprint.pformat([(key, value.get_value().shape)
                                    for key, value in params.items()],
                                   width=120))

        # Initialize parameters
        for brick in model.get_top_bricks():
            brick.initialize()

        # Fetch variables useful for debugging
        max_length = named_copy(chars.shape[0], "max_length")
        cost_per_character = named_copy(
            aggregation.mean(batch_cost, batch_size * max_length),
            "character_log_likelihood")
        cg = ComputationGraph(cost)
        (energies, ) = VariableFilter(application=readout.readout,
                                      name="output")(cg.variables)
        min_energy = named_copy(energies.min(), "min_energy")
        max_energy = named_copy(energies.max(), "max_energy")
        (activations, ) = VariableFilter(
            application=generator.transition.apply,
            name="states")(cg.variables)
        mean_activation = named_copy(
            abs(activations).mean(), "mean_activation")

        # Define the training algorithm.
        algorithm = GradientDescent(cost=cost,
                                    step_rule=CompositeRule(
                                        [StepClipping(10.0),
                                         Scale(0.01)]))

        # More variables for debugging
        observables = [
            cost, min_energy, max_energy, mean_activation, batch_size,
            max_length, cost_per_character, algorithm.total_step_norm,
            algorithm.total_gradient_norm
        ]
        for name, param in params.items():
            observables.append(named_copy(param.norm(2), name + "_norm"))
            observables.append(
                named_copy(algorithm.gradients[param].norm(2),
                           name + "_grad_norm"))

        # Construct the main loop and start training!
        average_monitoring = TrainingDataMonitoring(observables,
                                                    prefix="average",
                                                    every_n_batches=10)
        main_loop = MainLoop(
            model=model,
            data_stream=data_stream,
            algorithm=algorithm,
            extensions=[
                Timing(),
                TrainingDataMonitoring(observables, after_every_batch=True),
                average_monitoring,
                FinishAfter(after_n_batches=num_batches).add_condition(
                    "after_batch", _is_nan),
                Plot(os.path.basename(save_path),
                     [[average_monitoring.record_name(cost)],
                      [average_monitoring.record_name(cost_per_character)]],
                     every_n_batches=10),
                SerializeMainLoop(save_path,
                                  every_n_batches=500,
                                  save_separately=["model", "log"]),
                Printing(every_n_batches=1)
            ])
        main_loop.run()
    elif mode == "test":
        logger.info("Model is loaded")
        chars = tensor.lmatrix("features")
        generated = generator.generate(
            n_steps=3 * chars.shape[0],
            batch_size=chars.shape[1],
            attended=encoder.apply(**dict_union(
                fork.apply(lookup.lookup(chars), return_dict=True))),
            attended_mask=tensor.ones(chars.shape))
        model = Model(generated)
        model.set_param_values(load_parameter_values(save_path))
        sample_function = model.get_theano_function()
        logging.info("Sampling function is compiled")

        while True:
            # Python 2-3 compatibility
            line = input("Enter a sentence\n")
            batch_size = int(input("Enter a number of samples\n"))
            encoded_input = [
                char2code.get(char, char2code["<UNK>"])
                for char in line.lower().strip()
            ]
            encoded_input = ([char2code['<S>']] + encoded_input +
                             [char2code['</S>']])
            print("Encoder input:", encoded_input)
            target = reverse_words((encoded_input, ))[0]
            print("Target: ", target)
            states, samples, glimpses, weights, costs = sample_function(
                numpy.repeat(numpy.array(encoded_input)[:, None],
                             batch_size,
                             axis=1))

            messages = []
            for i in range(samples.shape[1]):
                sample = list(samples[:, i])
                try:
                    true_length = sample.index(char2code['</S>']) + 1
                except ValueError:
                    true_length = len(sample)
                sample = sample[:true_length]
                cost = costs[:true_length, i].sum()
                message = "({})".format(cost)
                message += "".join(code2char[code] for code in sample)
                if sample == target:
                    message += " CORRECT!"
                messages.append((cost, message))
            messages.sort(key=operator.itemgetter(0), reverse=True)
            for _, message in messages:
                print(message)
Exemple #9
0
def initialize_all(config, save_path, bokeh_name,
                   params, bokeh_server, bokeh, test_tag, use_load_ext,
                   load_log, fast_start):
    root_path, extension = os.path.splitext(save_path)

    data = Data(**config['data'])
    train_conf = config['training']
    recognizer = create_model(config, data, test_tag)

    # Separate attention_params to be handled differently
    # when regularization is applied
    attention = recognizer.generator.transition.attention
    attention_params = Selector(attention).get_parameters().values()

    logger.info(
        "Initialization schemes for all bricks.\n"
        "Works well only in my branch with __repr__ added to all them,\n"
        "there is an issue #463 in Blocks to do that properly.")

    def show_init_scheme(cur):
        result = dict()
        for attr in dir(cur):
            if attr.endswith('_init'):
                result[attr] = getattr(cur, attr)
        for child in cur.children:
            result[child.name] = show_init_scheme(child)
        return result
    logger.info(pprint.pformat(show_init_scheme(recognizer)))

    prediction, prediction_mask = add_exploration(recognizer, data, train_conf)

    #
    # Observables:
    #
    primary_observables = []  # monitored each batch
    secondary_observables = []  # monitored every 10 batches
    validation_observables = []  # monitored on the validation set

    cg = recognizer.get_cost_graph(
        batch=True, prediction=prediction, prediction_mask=prediction_mask)
    labels, = VariableFilter(
        applications=[recognizer.cost], name='labels')(cg)
    labels_mask, = VariableFilter(
        applications=[recognizer.cost], name='labels_mask')(cg)

    gain_matrix = VariableFilter(
        theano_name=RewardRegressionEmitter.GAIN_MATRIX)(cg)
    if len(gain_matrix):
        gain_matrix, = gain_matrix
        primary_observables.append(
            rename(gain_matrix.min(), 'min_gain'))
        primary_observables.append(
            rename(gain_matrix.max(), 'max_gain'))

    batch_cost = cg.outputs[0].sum()
    batch_size = rename(recognizer.labels.shape[1], "batch_size")
    # Assumes constant batch size. `aggregation.mean` is not used because
    # of Blocks #514.
    cost = batch_cost / batch_size
    cost.name = "sequence_total_cost"
    logger.info("Cost graph is built")

    # Fetch variables useful for debugging.
    # It is important not to use any aggregation schemes here,
    # as it's currently impossible to spread the effect of
    # regularization on their variables, see Blocks #514.
    cost_cg = ComputationGraph(cost)
    r = recognizer
    energies, = VariableFilter(
        applications=[r.generator.readout.readout], name="output_0")(
            cost_cg)
    bottom_output = VariableFilter(
        # We need name_regex instead of name because LookupTable calls itsoutput output_0
        applications=[r.bottom.apply], name_regex="output")(
            cost_cg)[-1]
    attended, = VariableFilter(
        applications=[r.generator.transition.apply], name="attended")(
            cost_cg)
    attended_mask, = VariableFilter(
        applications=[r.generator.transition.apply], name="attended_mask")(
            cost_cg)
    weights, = VariableFilter(
        applications=[r.generator.evaluate], name="weights")(
            cost_cg)
    max_recording_length = rename(bottom_output.shape[0],
                                  "max_recording_length")
    # To exclude subsampling related bugs
    max_attended_mask_length = rename(attended_mask.shape[0],
                                      "max_attended_mask_length")
    max_attended_length = rename(attended.shape[0],
                                 "max_attended_length")
    max_num_phonemes = rename(labels.shape[0],
                              "max_num_phonemes")
    min_energy = rename(energies.min(), "min_energy")
    max_energy = rename(energies.max(), "max_energy")
    mean_attended = rename(abs(attended).mean(),
                           "mean_attended")
    mean_bottom_output = rename(abs(bottom_output).mean(),
                                "mean_bottom_output")
    weights_penalty = rename(monotonicity_penalty(weights, labels_mask),
                             "weights_penalty")
    weights_entropy = rename(entropy(weights, labels_mask),
                             "weights_entropy")
    mask_density = rename(labels_mask.mean(),
                          "mask_density")
    cg = ComputationGraph([
        cost, weights_penalty, weights_entropy,
        min_energy, max_energy,
        mean_attended, mean_bottom_output,
        batch_size, max_num_phonemes,
        mask_density])
    # Regularization. It is applied explicitly to all variables
    # of interest, it could not be applied to the cost only as it
    # would not have effect on auxiliary variables, see Blocks #514.
    reg_config = config.get('regularization', dict())
    regularized_cg = cg
    if reg_config.get('dropout'):
        logger.info('apply dropout')
        regularized_cg = apply_dropout(cg, [bottom_output], 0.5)
    if reg_config.get('noise'):
        logger.info('apply noise')
        noise_subjects = [p for p in cg.parameters if p not in attention_params]
        regularized_cg = apply_noise(cg, noise_subjects, reg_config['noise'])

    train_cost = regularized_cg.outputs[0]
    if reg_config.get("penalty_coof", .0) > 0:
        # big warning!!!
        # here we assume that:
        # regularized_weights_penalty = regularized_cg.outputs[1]
        train_cost = (train_cost +
                      reg_config.get("penalty_coof", .0) *
                      regularized_cg.outputs[1] / batch_size)
    if reg_config.get("decay", .0) > 0:
        train_cost = (train_cost + reg_config.get("decay", .0) *
                      l2_norm(VariableFilter(roles=[WEIGHT])(cg.parameters)) ** 2)

    train_cost = rename(train_cost, 'train_cost')

    gradients = None
    if reg_config.get('adaptive_noise'):
        logger.info('apply adaptive noise')
        if ((reg_config.get("penalty_coof", .0) > 0) or
                (reg_config.get("decay", .0) > 0)):
            logger.error('using  adaptive noise with alignment weight panalty '
                         'or weight decay is probably stupid')
        train_cost, regularized_cg, gradients, noise_brick = apply_adaptive_noise(
            cg, cg.outputs[0],
            variables=cg.parameters,
            num_examples=data.get_dataset('train').num_examples,
            parameters=Model(regularized_cg.outputs[0]).get_parameter_dict().values(),
            **reg_config.get('adaptive_noise')
        )
        train_cost.name = 'train_cost'
        adapt_noise_cg = ComputationGraph(train_cost)
        model_prior_mean = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_prior_mean')(adapt_noise_cg)[0],
            'model_prior_mean')
        model_cost = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_cost')(adapt_noise_cg)[0],
            'model_cost')
        model_prior_variance = rename(
            VariableFilter(applications=[noise_brick.apply],
                           name='model_prior_variance')(adapt_noise_cg)[0],
            'model_prior_variance')
        regularized_cg = ComputationGraph(
            [train_cost, model_cost] +
            regularized_cg.outputs +
            [model_prior_mean, model_prior_variance])
        primary_observables += [
            regularized_cg.outputs[1],  # model cost
            regularized_cg.outputs[2],  # task cost
            regularized_cg.outputs[-2],  # model prior mean
            regularized_cg.outputs[-1]]  # model prior variance

    model = Model(train_cost)
    if params:
        logger.info("Load parameters from " + params)
        # please note: we cannot use recognizer.load_params
        # as it builds a new computation graph that dies not have
        # shapred variables added by adaptive weight noise
        with open(params, 'r') as src:
            param_values = load_parameters(src)
        model.set_parameter_values(param_values)

    parameters = model.get_parameter_dict()
    logger.info("Parameters:\n" +
                pprint.pformat(
                    [(key, parameters[key].get_value().shape) for key
                     in sorted(parameters.keys())],
                    width=120))

    # Define the training algorithm.
    clipping = StepClipping(train_conf['gradient_threshold'])
    clipping.threshold.name = "gradient_norm_threshold"
    rule_names = train_conf.get('rules', ['momentum'])
    core_rules = []
    if 'momentum' in rule_names:
        logger.info("Using scaling and momentum for training")
        core_rules.append(Momentum(train_conf['scale'], train_conf['momentum']))
    if 'adadelta' in rule_names:
        logger.info("Using AdaDelta for training")
        core_rules.append(AdaDelta(train_conf['decay_rate'], train_conf['epsilon']))
    max_norm_rules = []
    if reg_config.get('max_norm', False) > 0:
        logger.info("Apply MaxNorm")
        maxnorm_subjects = VariableFilter(roles=[WEIGHT])(cg.parameters)
        if reg_config.get('max_norm_exclude_lookup', False):
            maxnorm_subjects = [v for v in maxnorm_subjects
                                if not isinstance(get_brick(v), LookupTable)]
        logger.info("Parameters covered by MaxNorm:\n"
                    + pprint.pformat([name for name, p in parameters.items()
                                      if p in maxnorm_subjects]))
        logger.info("Parameters NOT covered by MaxNorm:\n"
                    + pprint.pformat([name for name, p in parameters.items()
                                      if not p in maxnorm_subjects]))
        max_norm_rules = [
            Restrict(VariableClipping(reg_config['max_norm'], axis=0),
                     maxnorm_subjects)]
    burn_in = []
    if train_conf.get('burn_in_steps', 0):
        burn_in.append(
            BurnIn(num_steps=train_conf['burn_in_steps']))
    algorithm = GradientDescent(
        cost=train_cost,
        parameters=parameters.values(),
        gradients=gradients,
        step_rule=CompositeRule(
            [clipping] + core_rules + max_norm_rules +
            # Parameters are not changed at all
            # when nans are encountered.
            [RemoveNotFinite(0.0)] + burn_in),
        on_unused_sources='warn')

    logger.debug("Scan Ops in the gradients")
    gradient_cg = ComputationGraph(algorithm.gradients.values())
    for op in ComputationGraph(gradient_cg).scans:
        logger.debug(op)

    # More variables for debugging: some of them can be added only
    # after the `algorithm` object is created.
    secondary_observables += list(regularized_cg.outputs)
    if not 'train_cost' in [v.name for v in secondary_observables]:
        secondary_observables += [train_cost]
    secondary_observables += [
        algorithm.total_step_norm, algorithm.total_gradient_norm,
        clipping.threshold]
    for name, param in parameters.items():
        num_elements = numpy.product(param.get_value().shape)
        norm = param.norm(2) / num_elements ** 0.5
        grad_norm = algorithm.gradients[param].norm(2) / num_elements ** 0.5
        step_norm = algorithm.steps[param].norm(2) / num_elements ** 0.5
        stats = tensor.stack(norm, grad_norm, step_norm, step_norm / grad_norm)
        stats.name = name + '_stats'
        secondary_observables.append(stats)

    primary_observables += [
        train_cost,
        algorithm.total_gradient_norm,
        algorithm.total_step_norm, clipping.threshold,
        max_recording_length,
        max_attended_length, max_attended_mask_length]

    validation_observables += [
        rename(aggregation.mean(batch_cost, batch_size), cost.name),
        rename(aggregation.sum_(batch_size), 'num_utterances'),
        weights_entropy, weights_penalty]

    def attach_aggregation_schemes(variables):
        # Aggregation specification has to be factored out as a separate
        # function as it has to be applied at the very last stage
        # separately to training and validation observables.
        result = []
        for var in variables:
            if var.name == 'weights_penalty':
                result.append(rename(aggregation.mean(var, batch_size),
                                     'weights_penalty_per_recording'))
            elif var.name == 'weights_entropy':
                result.append(rename(aggregation.mean(var, labels_mask.sum()),
                                     'weights_entropy_per_label'))
            else:
                result.append(var)
        return result

    mon_conf = config['monitoring']

    # Build main loop.
    logger.info("Initialize extensions")
    extensions = []
    if use_load_ext and params:
        extensions.append(Load(params, load_iteration_state=True, load_log=True))
    if load_log and params:
        extensions.append(LoadLog(params))
    extensions += [
        Timing(after_batch=True),
        CGStatistics(),
        #CodeVersion(['lvsr']),
    ]
    extensions.append(TrainingDataMonitoring(
        primary_observables, after_batch=True))
    average_monitoring = TrainingDataMonitoring(
        attach_aggregation_schemes(secondary_observables),
        prefix="average", every_n_batches=10)
    extensions.append(average_monitoring)
    validation = DataStreamMonitoring(
        attach_aggregation_schemes(validation_observables),
        data.get_stream("valid", shuffle=False), prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=mon_conf['validate_every_epochs'],
            every_n_batches=mon_conf['validate_every_batches'],
            after_training=False)
    extensions.append(validation)
    per = PhonemeErrorRate(recognizer, data,
                           **config['monitoring']['search'])
    per_monitoring = DataStreamMonitoring(
        [per], data.get_stream("valid", batches=False, shuffle=False),
        prefix="valid").set_conditions(
            before_first_epoch=not fast_start,
            every_n_epochs=mon_conf['search_every_epochs'],
            every_n_batches=mon_conf['search_every_batches'],
            after_training=False)
    extensions.append(per_monitoring)
    track_the_best_per = TrackTheBest(
        per_monitoring.record_name(per)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    track_the_best_cost = TrackTheBest(
        validation.record_name(cost)).set_conditions(
            before_first_epoch=True, after_epoch=True)
    extensions += [track_the_best_cost, track_the_best_per]
    extensions.append(AdaptiveClipping(
        algorithm.total_gradient_norm.name,
        clipping, train_conf['gradient_threshold'],
        decay_rate=0.998, burnin_period=500))
    extensions += [
        SwitchOffLengthFilter(
            data.length_filter,
            after_n_batches=train_conf.get('stop_filtering')),
        FinishAfter(after_n_batches=train_conf.get('num_batches'),
                    after_n_epochs=train_conf.get('num_epochs'))
            .add_condition(["after_batch"], _gradient_norm_is_none),
    ]
    channels = [
        # Plot 1: training and validation costs
        [average_monitoring.record_name(train_cost),
         validation.record_name(cost)],
        # Plot 2: gradient norm,
        [average_monitoring.record_name(algorithm.total_gradient_norm),
         average_monitoring.record_name(clipping.threshold)],
        # Plot 3: phoneme error rate
        [per_monitoring.record_name(per)],
        # Plot 4: training and validation mean weight entropy
        [average_monitoring._record_name('weights_entropy_per_label'),
         validation._record_name('weights_entropy_per_label')],
        # Plot 5: training and validation monotonicity penalty
        [average_monitoring._record_name('weights_penalty_per_recording'),
         validation._record_name('weights_penalty_per_recording')]]
    if bokeh:
        extensions += [
            Plot(bokeh_name if bokeh_name
                 else os.path.basename(save_path),
                 channels,
                 every_n_batches=10,
                 server_url=bokeh_server),]
    extensions += [
        Checkpoint(save_path,
                   before_first_epoch=not fast_start, after_epoch=True,
                   every_n_batches=train_conf.get('save_every_n_batches'),
                   save_separately=["model", "log"],
                   use_cpickle=True)
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_per.notification_name),
            (root_path + "_best" + extension,))
        .add_condition(
            ['after_epoch'],
            OnLogRecord(track_the_best_cost.notification_name),
            (root_path + "_best_ll" + extension,)),
        ProgressBar()]
    extensions.append(EmbedIPython(use_main_loop_run_caller_env=True))
    if config['net']['criterion']['name'].startswith('mse'):
        extensions.append(
            LogInputsGains(
                labels, cg, recognizer.generator.readout.emitter, data))

    if train_conf.get('patience'):
        patience_conf = train_conf['patience']
        if not patience_conf.get('notification_names'):
            # setdefault will not work for empty list
            patience_conf['notification_names'] = [
                track_the_best_per.notification_name,
                track_the_best_cost.notification_name]
        extensions.append(Patience(**patience_conf))

    extensions.append(Printing(every_n_batches=1,
                               attribute_filter=PrintingFilterList()))

    return model, algorithm, data, extensions