# Copyright 2018 The TensorFlow Authors. All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ============================================================================== """Part of the Keras training engine related to plain array data.""" import functools import numpy as np import tensorflow.compat.v2 as tf from keras import backend from keras import callbacks as cbks from keras.distribute import distributed_training_utils_v1 from keras.engine import training_utils_v1 from keras.utils import io_utils from keras.utils.generic_utils import make_batches from keras.utils.generic_utils import slice_arrays from keras.utils.mode_keys import ModeKeys # isort: off from tensorflow.python.platform import tf_logging as logging try: from scipy.sparse import issparse except ImportError: issparse = None def model_iteration( model, inputs, targets=None, sample_weights=None, batch_size=None, epochs=1, verbose=1, callbacks=None, val_inputs=None, val_targets=None, val_sample_weights=None, shuffle=True, initial_epoch=0, steps_per_epoch=None, validation_steps=None, validation_freq=1, mode=ModeKeys.TRAIN, validation_in_fit=False, prepared_feed_values_from_dataset=False, steps_name="steps", **kwargs, ): """Loop function for arrays of data with modes TRAIN/TEST/PREDICT. Args: model: Keras Model instance. inputs: Either a list or dictionary of arrays, or a dataset instance. targets: List/dictionary of input arrays. sample_weights: Optional list of sample weight arrays. batch_size: Integer batch size or None if unknown. epochs: Number of times to iterate over the data verbose: 0, 1, or 2. Verbosity mode. 0 = silent, 1 = progress bar, 2 = one line per epoch. Note that the progress bar is not particularly useful when logged to a file, so verbose=2 is recommended when not running interactively (eg, in a production environment). callbacks: List of callbacks to be called during training val_inputs: Either a list or dictionary of arrays, or a dataset instance. val_targets: List/dictionary of target arrays. val_sample_weights: Optional list of sample weight arrays. shuffle: Whether to shuffle the data at the beginning of each epoch concatenation of list the display names of the outputs of `f` and the list of display names of the outputs of `f_val`. initial_epoch: Epoch at which to start training (useful for resuming a previous training run) steps_per_epoch: Total number of steps (batches of samples) before declaring one epoch finished and starting the next epoch. Ignored with the default value of `None`. validation_steps: Number of steps to run validation for (only if doing validation from data tensors). Ignored with the default value of `None`. validation_freq: Only relevant if validation data is provided. Integer or `collections.abc.Container` instance (e.g. list, tuple, etc.). If an integer, specifies how many training epochs to run before a new validation run is performed, e.g. `validation_freq=2` runs validation every 2 epochs. If a Container, specifies the epochs on which to run validation, e.g. `validation_freq=[1, 2, 10]` runs validation at the end of the 1st, 2nd, and 10th epochs. mode: One of ModeKeys.TRAIN/ModeKeys.TEST/ModeKeys.PREDICT. validation_in_fit: if true, then this method is invoked from within training iteration (for validation). In the case where `val_inputs` is a dataset, this flag indicates that its iterator and feed values are already created so should properly reuse resources. prepared_feed_values_from_dataset: if True, `inputs` is a list of feed tensors returned from `_prepare_feed_values` call on the validation dataset, so do not call it again on `inputs`. Should only be used for inline validation (i.e., only if `validation_in_fit` is also True). steps_name: The string name of the steps argument, either `steps`, `validation_steps`, or `steps_per_epoch`. Only used for error message formatting. **kwargs: Additional arguments for backwards compatibility. Returns: - In TRAIN mode: `History` object. - In TEST mode: Evaluation metrics. - In PREDICT mode: Outputs of the Model called on inputs. Raises: ValueError: in case of invalid arguments. """ # Backwards compatibility. if "steps" in kwargs: steps_per_epoch = kwargs.pop("steps") if kwargs: raise TypeError(f"Unknown arguments: {kwargs}") # In case we were passed a dataset, we extract symbolic tensors from it. reset_dataset_after_each_epoch = False input_iterator = None is_dataset = isinstance( inputs, (tf.compat.v1.data.Dataset, tf.data.Dataset) ) # TODO(fchollet): consider moving `steps_per_epoch` inference to # _standardize_user_data and set reset_dataset_after_each_epoch as an # attribute on the dataset instance. if is_dataset: if steps_per_epoch is None: reset_dataset_after_each_epoch = True steps_per_epoch = training_utils_v1.infer_steps_for_dataset( model, inputs, steps_per_epoch, epochs=epochs, steps_name=steps_name, ) input_iterator = _get_iterator(inputs, model._distribution_strategy) # Enter tf.distribute.Strategy scope. if model._distribution_strategy: scope = distributed_training_utils_v1.distributed_scope( strategy=model._distribution_strategy, learning_phase=(1 if mode == ModeKeys.TRAIN else 0), ) scope.__enter__() use_steps = is_dataset or steps_per_epoch is not None do_validation = val_inputs is not None # Prepare input data. inputs = input_iterator or inputs if validation_in_fit and prepared_feed_values_from_dataset: # When invoking validation in training loop, avoid creating iterator and # list of feed values for the same validation dataset multiple times # (which essentially would call `iterator.get_next()` that slows down # execution and leads to OOM errors eventually. ins = inputs else: ins = _prepare_feed_values(model, inputs, targets, sample_weights, mode) # `ins` is a function when a distribute strategy is used in Eager mode. # In that case `is_dataset` is True. The code branches that have # requirements about the type of `ins` do not trigger in the distributed # case. if not is_dataset: num_samples_or_steps = _get_num_samples_or_steps( ins, batch_size, steps_per_epoch ) else: num_samples_or_steps = steps_per_epoch # Update sample_weight_mode of the model if sample_weights is specified by # the user. We need to call this function after we have a handle on the # inputs (both numpy arrays and datasets) in order to determine if the user # has specified sample_weights. _update_sample_weight_mode(model, mode, ins) # Get step function and loop type. As part of building the execution # function we recompile the metrics based on the updated # sample_weight_mode value. f = _make_execution_function(model, mode) # Prepare validation data. Hold references to the iterator and the input # list to properly reinitialize and reuse in multiple validation passes. val_iterator = None if isinstance(val_inputs, (tf.compat.v1.data.Dataset, tf.data.Dataset)): if validation_steps is None: # Because we pass an iterator feed instead of a Dataset to the eval # model_iteration() call, it will not trigger the dataset-input path # that determines the number of steps required. To avoid this issue, # set validation_steps here if validation_steps is None. validation_steps = training_utils_v1.infer_steps_for_dataset( model, val_inputs, validation_steps, epochs=epochs, steps_name="validation_steps", ) val_iterator = _get_iterator(val_inputs, model._distribution_strategy) val_inputs = _prepare_feed_values( model, val_iterator, val_targets, val_sample_weights, ModeKeys.TEST ) # Get num steps for printing. val_samples_or_steps = validation_steps else: # Get num samples for printing. val_samples_or_steps = ( val_inputs and tf.nest.flatten(val_inputs)[0].shape[0] or None ) if mode == ModeKeys.TRAIN and verbose: _print_train_info( num_samples_or_steps, val_samples_or_steps, is_dataset ) # Configure callbacks. count_mode = "steps" if use_steps else "samples" callbacks = cbks.configure_callbacks( callbacks, model, do_validation=do_validation, batch_size=batch_size, epochs=epochs, steps_per_epoch=steps_per_epoch, samples=num_samples_or_steps, count_mode=count_mode, verbose=verbose, mode=mode, ) # Find beforehand arrays that need sparse-to-dense conversion. if issparse is not None and not use_steps: indices_for_conversion_to_dense = [] feed = _get_model_feed(model, mode) for i, (input_data, feed_tensor) in enumerate(zip(ins, feed)): if issparse(input_data) and not backend.is_sparse(feed_tensor): indices_for_conversion_to_dense.append(i) # Select aggregation method. if mode == ModeKeys.PREDICT: aggregator = training_utils_v1.OutputsAggregator( use_steps, num_samples=None if steps_per_epoch else num_samples_or_steps, steps=steps_per_epoch, ) else: aggregator = training_utils_v1.MetricsAggregator( use_steps, num_samples=None if steps_per_epoch else num_samples_or_steps, steps=steps_per_epoch, ) if model._compile_distribution: distributed_training_utils_v1._copy_weights_to_distributed_model( model, mode ) callbacks.model.stop_training = False callbacks._call_begin_hook(mode) initial_epoch = model._maybe_load_initial_epoch_from_ckpt( initial_epoch, mode ) for epoch in range(initial_epoch, epochs): if callbacks.model.stop_training: break # Setup work for each epoch epoch_logs = {} if mode != ModeKeys.PREDICT: # Collecting and resetting metrics has non-zero cost and will # needlessly slow down model.predict. model.reset_metrics() if mode == ModeKeys.TRAIN: callbacks.on_epoch_begin(epoch, epoch_logs) if use_steps: # Step-wise loop. if steps_per_epoch is None: # Loop over dataset until `OutOfRangeError` is raised. target_steps = np.inf else: # Loop over dataset for the specified number of steps. target_steps = steps_per_epoch step = 0 while step < target_steps: batch_logs = {"batch": step, "size": 1} callbacks._call_batch_hook(mode, "begin", step, batch_logs) # Get outputs. try: # `ins` can be callable in tf.distribute.Strategy + eager # case. if not callable(ins) or ( model._distribution_strategy and not distributed_training_utils_v1.is_distributing_by_cloning( # noqa: E501 model ) ): actual_inputs = ins else: actual_inputs = ins() batch_outs = f(actual_inputs) except tf.errors.OutOfRangeError: if is_dataset: # The dataset passed by the user ran out of batches. # Now we know the cardinality of the dataset. If # steps_per_epoch was specified, then running out of # data is unexpected, so we stop training and inform the # user. if steps_per_epoch: callbacks.model.stop_training = True logging.warning( "Your dataset ran out of data; interrupting " "training. Make sure that your dataset can " "generate at least `%s * epochs` batches (in " "this case, %d batches). You may need to use " "the repeat() function when building your " "dataset." % (steps_name, steps_per_epoch * epochs) ) elif step > 0: steps_per_epoch = step aggregator.steps = steps_per_epoch else: # We ran out of batches while the user passed an # iterator (legacy). callbacks.model.stop_training = True logging.warning( "Your dataset iterator ran out of data; " "interrupting training. Make sure that your " "iterator can generate at least `%s * epochs` " "batches (in this case, %d batches). You may need " "to use the repeat() function when building your " "dataset." % (steps_name, steps_per_epoch * epochs) ) break if not isinstance(batch_outs, list): batch_outs = [batch_outs] if model._distribution_strategy: batch_outs = distributed_training_utils_v1._per_replica_aggregate_batch( # noqa: E501 model._distribution_strategy, batch_outs, model, mode ) # Aggregate results. if step == 0: aggregator.create(batch_outs) aggregator.aggregate(batch_outs) # Callbacks batch end. batch_logs = callbacks.make_logs( model, batch_logs, batch_outs, mode ) callbacks._call_batch_hook(mode, "end", step, batch_logs) step += 1 if callbacks.model.stop_training: break else: # Sample-wise loop. index_array = np.arange(num_samples_or_steps) if shuffle == "batch": index_array = training_utils_v1.batch_shuffle( index_array, batch_size ) elif shuffle: np.random.shuffle(index_array) batches = make_batches(num_samples_or_steps, batch_size) for batch_index, (batch_start, batch_end) in enumerate(batches): batch_ids = index_array[batch_start:batch_end] # Slice into a batch. if len(batches) == 1: # If we only have one batch, do not slice. This takes care # of composite tensors in non-Dataset modes; we currently # don't support slicing them. # TODO(b/133517906): Add slicing support. ins_batch = ins else: try: if ins and isinstance(ins[-1], int): # Do not slice the training phase flag. ins_batch = slice_arrays(ins[:-1], batch_ids) + [ ins[-1] ] else: ins_batch = slice_arrays(ins, batch_ids) except TypeError: raise TypeError( "TypeError while preparing batch. " "If using HDF5 input data, " 'pass shuffle="batch".' ) # Sparse to dense conversion. if issparse is not None: for i in indices_for_conversion_to_dense: ins_batch[i] = ins_batch[i].toarray() # Callbacks batch_begin. batch_logs = {"batch": batch_index, "size": len(batch_ids)} callbacks._call_batch_hook( mode, "begin", batch_index, batch_logs ) # Get outputs. batch_outs = f(ins_batch) if not isinstance(batch_outs, list): batch_outs = [batch_outs] # Aggregate results. if batch_index == 0: aggregator.create(batch_outs) aggregator.aggregate(batch_outs, batch_start, batch_end) # Callbacks batch end. batch_logs = callbacks.make_logs( model, batch_logs, batch_outs, mode ) callbacks._call_batch_hook(mode, "end", batch_index, batch_logs) if callbacks.model.stop_training: break aggregator.finalize() results = aggregator.results epoch_logs = callbacks.make_logs(model, epoch_logs, results, mode) if len(results) == 1: results = results[0] # Run the test loop every `validation_freq` epochs during training. if ( do_validation and training_utils_v1.should_run_validation(validation_freq, epoch) and not callbacks.model.stop_training ): if model._compile_distribution: # Since we create a new clone from the original model we need to # copy the weights back to the original model before we can run # validation. distributed_training_utils_v1._copy_weights_to_original_model( model, ModeKeys.TRAIN ) val_results = model_iteration( model, val_inputs, targets=val_targets, sample_weights=val_sample_weights, batch_size=batch_size, steps_per_epoch=validation_steps, callbacks=callbacks, verbose=0, mode=ModeKeys.TEST, validation_in_fit=True, prepared_feed_values_from_dataset=(val_iterator is not None), steps_name="validation_steps", ) if not isinstance(val_results, list): val_results = [val_results] epoch_logs = callbacks.make_logs( model, epoch_logs, val_results, mode, prefix="val_" ) if val_iterator and epoch < epochs - 1: _reinitialize_iterator( val_iterator, model._distribution_strategy ) if mode == ModeKeys.TRAIN: # Epochs only apply to `fit`. callbacks.on_epoch_end(epoch, epoch_logs) # Reinitialize dataset iterator for the next epoch. if reset_dataset_after_each_epoch and epoch < epochs - 1: _reinitialize_iterator(input_iterator, model._distribution_strategy) model._successful_loop_finish = True callbacks._call_end_hook(mode) if model._distribution_strategy: if model._compile_distribution: # TODO(priyag, psv): Copy back metrics to the original model as # well? distributed_training_utils_v1._copy_weights_to_original_model( model, mode ) scope.__exit__(None, None, None) if mode == ModeKeys.TRAIN: return model.history return results def _get_model_feed(model, mode): if mode == ModeKeys.PREDICT: feed = model._feed_inputs else: feed = ( model._feed_inputs + model._feed_targets + model._feed_sample_weights ) return feed def _print_train_info(num_samples_or_steps, val_samples_or_steps, is_dataset): increment = "steps" if is_dataset else "samples" msg = f"Train on {num_samples_or_steps} {increment}" if val_samples_or_steps: msg += f", validate on {val_samples_or_steps} {increment}" io_utils.print_msg(msg) def _get_num_samples_or_steps(ins, batch_size, steps_per_epoch): """Returns total number of samples when training in batch mode or steps.""" if steps_per_epoch: return steps_per_epoch return training_utils_v1.check_num_samples( ins, batch_size, steps_per_epoch, "steps_per_epoch" ) def _prepare_feed_values(model, inputs, targets, sample_weights, mode): """Prepare feed values to the model execution function. Args: model: Model to prepare feed values for. inputs: List or dict of model inputs. targets: Optional list of model targets. sample_weights: Optional list of sample weight arrays. mode: One of ModeKeys.TRAIN/ModeKeys.TEST/ModeKeys.PREDICT. Returns: Feed values for the model in the given mode. """ if model._distribution_strategy: if isinstance(inputs, (tf.compat.v1.data.Dataset, tf.data.Dataset)): inputs = distributed_training_utils_v1.get_iterator( inputs, model._distribution_strategy ) def get_distributed_inputs(): return distributed_training_utils_v1._prepare_feed_values( model, inputs, targets, sample_weights, mode ) # In the eager case, we want to call the input method per step, so # return a lambda from here that can be called. Note that this is # applicable only in Distribution Strategy case as it follows the same # code path for both eager and graph modes. # TODO(priyag,omalleyt): Either we should move the training DS with # IteratorBase to use training_generator code path, or figure out how to # set a symbolic Iterator out of a Dataset when in eager mode. if tf.executing_eagerly(): return get_distributed_inputs else: return get_distributed_inputs() if isinstance( inputs, ( tf.compat.v1.data.Dataset, tf.data.Dataset, tf.compat.v1.data.Iterator, ), ): inputs, targets, sample_weights = model._standardize_user_data( inputs, extract_tensors_from_dataset=True ) inputs = training_utils_v1.ModelInputs(inputs).as_list() targets = list(targets or []) sample_weights = list(sample_weights or []) ins = inputs + targets + sample_weights if mode == ModeKeys.TRAIN and not isinstance( backend.symbolic_learning_phase(), int ): ins += [True] # Add learning phase value. return ins def _get_iterator(inputs, distribution_strategy=None): if distribution_strategy: return distributed_training_utils_v1.get_iterator( inputs, distribution_strategy ) return training_utils_v1.get_iterator(inputs) def _reinitialize_iterator(iterator, distribution_strategy=None): if distribution_strategy: distributed_training_utils_v1.initialize_iterator( iterator, distribution_strategy ) else: training_utils_v1.initialize_iterator(iterator) def _make_execution_function(model, mode): """Makes function to run one step of model execution.""" if model._distribution_strategy: return distributed_training_utils_v1._make_execution_function( model, mode ) return model._make_execution_function(mode) def _update_sample_weight_mode(model, mode, inputs): """Updates the sample_weight_mode of a given model.""" # Add a quick return to prevent us from calling model._feed_targets that # accesses certain model properties that may not be set in the `PREDICT` # mode. if mode == ModeKeys.PREDICT: return sample_weights = None # `inputs` is the model's inputs + targets + sample_weights + # learning phase placeholder if specified. To update the sample_weight_mode # we need to determine if the user has passed sample weights as part of the # input. if not callable(inputs): sample_weights = inputs[ len(model._feed_inputs) + len(model._feed_targets) : ] has_learning_phase_pl = mode == ModeKeys.TRAIN and not isinstance( backend.symbolic_learning_phase(), int ) if has_learning_phase_pl: sample_weights = sample_weights[:-1] model._update_sample_weight_modes(sample_weights=sample_weights) # Call the DistributionStrategy specific function to update the # sample_weight_mode on the model. if model._distribution_strategy: distributed_training_utils_v1._update_sample_weight_modes( model, mode, sample_weights ) # For backwards compatibility for internal users of these loops. fit_loop = functools.partial(model_iteration, mode=ModeKeys.TRAIN) test_loop = functools.partial( model_iteration, mode=ModeKeys.TEST, shuffle=False ) predict_loop = functools.partial( model_iteration, mode=ModeKeys.PREDICT, shuffle=False ) class ArrayLikeTrainingLoop(training_utils_v1.TrainingLoop): """TrainingLoop that handle inputs like array. This is the default handler for most of the input data types, includes symbolic tensors or Numpy array-like, Datasets and iterators in graph mode (since they generate symbolic tensors). This Function is used to handle model with `run_eagerly` = False. """ def fit( self, model, x=None, y=None, batch_size=None, epochs=1, verbose=1, callbacks=None, validation_split=0.0, validation_data=None, shuffle=True, class_weight=None, sample_weight=None, initial_epoch=0, steps_per_epoch=None, validation_steps=None, validation_freq=1, **kwargs, ): batch_size = model._validate_or_infer_batch_size( batch_size, steps_per_epoch, x ) x, y, sample_weights = model._standardize_user_data( x, y, sample_weight=sample_weight, class_weight=class_weight, batch_size=batch_size, check_steps=True, steps_name="steps_per_epoch", steps=steps_per_epoch, validation_split=validation_split, shuffle=shuffle, ) if validation_data: val_x, val_y, val_sample_weights = model._prepare_validation_data( validation_data, batch_size, validation_steps ) elif validation_split and 0.0 < validation_split < 1.0: ( x, y, sample_weights, val_x, val_y, val_sample_weights, ) = training_utils_v1.split_training_and_validation_data( x, y, sample_weights, validation_split ) else: if validation_steps: raise ValueError( "`validation_steps` should not be specified if " "`validation_data` is None." ) val_x, val_y, val_sample_weights = None, None, None return fit_loop( model, inputs=x, targets=y, sample_weights=sample_weights, batch_size=batch_size, epochs=epochs, verbose=verbose, callbacks=callbacks, val_inputs=val_x, val_targets=val_y, val_sample_weights=val_sample_weights, shuffle=shuffle, initial_epoch=initial_epoch, steps_per_epoch=steps_per_epoch, validation_steps=validation_steps, validation_freq=validation_freq, steps_name="steps_per_epoch", ) def evaluate( self, model, x=None, y=None, batch_size=None, verbose=1, sample_weight=None, steps=None, callbacks=None, **kwargs, ): batch_size = model._validate_or_infer_batch_size(batch_size, steps, x) x, y, sample_weights = model._standardize_user_data( x, y, sample_weight=sample_weight, batch_size=batch_size, check_steps=True, steps_name="steps", steps=steps, ) return test_loop( model, inputs=x, targets=y, sample_weights=sample_weights, batch_size=batch_size, verbose=verbose, steps=steps, callbacks=callbacks, ) def predict( self, model, x, batch_size=None, verbose=0, steps=None, callbacks=None, **kwargs, ): batch_size = model._validate_or_infer_batch_size(batch_size, steps, x) x, _, _ = model._standardize_user_data( x, check_steps=True, steps_name="steps", steps=steps ) return predict_loop( model, x, batch_size=batch_size, verbose=verbose, steps=steps, callbacks=callbacks, )