def train(self, progress_bar=False):
checkpoint_params = self.checkpoint_params
train_start_time = time.time() + self.checkpoint_params.total_time
self.dataset.load_samples(processes=1, progress_bar=progress_bar)
datas, txts = self.dataset.train_samples(skip_empty=checkpoint_params.skip_invalid_gt)
if len(datas) == 0:
raise Exception("Empty dataset is not allowed. Check if the data is at the correct location")
if self.validation_dataset:
self.validation_dataset.load_samples(processes=1, progress_bar=progress_bar)
validation_datas, validation_txts = self.validation_dataset.train_samples(skip_empty=checkpoint_params.skip_invalid_gt)
if len(validation_datas) == 0:
raise Exception("Validation dataset is empty. Provide valid validation data for early stopping.")
else:
validation_datas, validation_txts = [], []
# preprocessing steps
texts = self.txt_preproc.apply(txts, processes=checkpoint_params.processes, progress_bar=progress_bar)
datas = self.data_preproc.apply(datas, processes=checkpoint_params.processes, progress_bar=progress_bar)
validation_txts = self.txt_preproc.apply(validation_txts, processes=checkpoint_params.processes, progress_bar=progress_bar)
validation_datas = self.data_preproc.apply(validation_datas, processes=checkpoint_params.processes, progress_bar=progress_bar)
# compute the codec
codec = self.codec if self.codec else Codec.from_texts(texts, whitelist=self.codec_whitelist)
# data augmentation on preprocessed data
if self.data_augmenter:
datas, texts = self.data_augmenter.augment_datas(datas, texts, n_augmentations=self.n_augmentations,
processes=checkpoint_params.processes, progress_bar=progress_bar)
# TODO: validation data augmentation
# validation_datas, validation_txts = self.data_augmenter.augment_datas(validation_datas, validation_txts, n_augmentations=0,
# processes=checkpoint_params.processes, progress_bar=progress_bar)
# create backend
network_params = checkpoint_params.model.network
network_params.features = checkpoint_params.model.line_height
network_params.classes = len(codec)
if self.weights:
# if we load the weights, take care of codec changes as-well
with open(self.weights + '.json', 'r') as f:
restore_checkpoint_params = json_format.Parse(f.read(), CheckpointParams())
restore_model_params = restore_checkpoint_params.model
# checks
if checkpoint_params.model.line_height != network_params.features:
raise Exception("The model to restore has a line height of {} but a line height of {} is requested".format(
network_params.features, checkpoint_params.model.line_height
))
# create codec of the same type
restore_codec = codec.__class__(restore_model_params.codec.charset)
# the codec changes as tuple (deletions/insertions), and the new codec is the changed old one
codec_changes = restore_codec.align(codec)
codec = restore_codec
print("Codec changes: {} deletions, {} appends".format(len(codec_changes[0]), len(codec_changes[1])))
# The actual weight/bias matrix will be changed after loading the old weights
else:
codec_changes = None
# store the new codec
checkpoint_params.model.codec.charset[:] = codec.charset
print("CODEC: {}".format(codec.charset))
# compute the labels with (new/current) codec
labels = [codec.encode(txt) for txt in texts]
backend = create_backend_from_proto(network_params,
weights=self.weights,
)
backend.set_train_data(datas, labels)
backend.set_prediction_data(validation_datas)
if codec_changes:
backend.realign_model_labels(*codec_changes)
backend.prepare(train=True)
loss_stats = RunningStatistics(checkpoint_params.stats_size, checkpoint_params.loss_stats)
ler_stats = RunningStatistics(checkpoint_params.stats_size, checkpoint_params.ler_stats)
dt_stats = RunningStatistics(checkpoint_params.stats_size, checkpoint_params.dt_stats)
early_stopping_enabled = self.validation_dataset is not None \
and checkpoint_params.early_stopping_frequency > 0 \
and checkpoint_params.early_stopping_nbest > 1
early_stopping_best_accuracy = checkpoint_params.early_stopping_best_accuracy
early_stopping_best_cur_nbest = checkpoint_params.early_stopping_best_cur_nbest
early_stopping_best_at_iter = checkpoint_params.early_stopping_best_at_iter
early_stopping_predictor = Predictor(codec=codec, text_postproc=self.txt_postproc,
backend=backend)
# Start the actual training
# ====================================================================================
iter = checkpoint_params.iter
# helper function to write a checkpoint
def make_checkpoint(base_dir, prefix, version=None):
if version:
checkpoint_path = os.path.abspath(os.path.join(base_dir, "{}{}.ckpt".format(prefix, version)))
else:
checkpoint_path = os.path.abspath(os.path.join(base_dir, "{}{:08d}.ckpt".format(prefix, iter + 1)))
print("Storing checkpoint to '{}'".format(checkpoint_path))
backend.save_checkpoint(checkpoint_path)
checkpoint_params.iter = iter
checkpoint_params.loss_stats[:] = loss_stats.values
checkpoint_params.ler_stats[:] = ler_stats.values
checkpoint_params.dt_stats[:] = dt_stats.values
checkpoint_params.total_time = time.time() - train_start_time
checkpoint_params.early_stopping_best_accuracy = early_stopping_best_accuracy
checkpoint_params.early_stopping_best_cur_nbest = early_stopping_best_cur_nbest
checkpoint_params.early_stopping_best_at_iter = early_stopping_best_at_iter
with open(checkpoint_path + ".json", 'w') as f:
f.write(json_format.MessageToJson(checkpoint_params))
return checkpoint_path
try:
last_checkpoint = None
# Training loop, can be interrupted by early stopping
for iter in range(iter, checkpoint_params.max_iters):
checkpoint_params.iter = iter
iter_start_time = time.time()
result = backend.train_step(checkpoint_params.batch_size)
if not np.isfinite(result['loss']):
print("Error: Loss is not finite! Trying to restart from last checkpoint.")
if not last_checkpoint:
raise Exception("No checkpoint written yet. Training must be stopped.")
else:
# reload also non trainable weights, such as solver-specific variables
backend.load_checkpoint_weights(last_checkpoint, restore_only_trainable=False)
continue
loss_stats.push(result['loss'])
ler_stats.push(result['ler'])
dt_stats.push(time.time() - iter_start_time)
if iter % checkpoint_params.display == 0:
pred_sentence = self.txt_postproc.apply("".join(codec.decode(result["decoded"][0])))
gt_sentence = self.txt_postproc.apply("".join(codec.decode(result["gt"][0])))
print("#{:08d}: loss={:.8f} ler={:.8f} dt={:.8f}s".format(iter, loss_stats.mean(), ler_stats.mean(), dt_stats.mean()))
print(" PRED: '{}'".format(pred_sentence))
print(" TRUE: '{}'".format(gt_sentence))
if (iter + 1) % checkpoint_params.checkpoint_frequency == 0:
last_checkpoint = make_checkpoint(checkpoint_params.output_dir, checkpoint_params.output_model_prefix)
if early_stopping_enabled and (iter + 1) % checkpoint_params.early_stopping_frequency == 0:
print("Checking early stopping model")
out = early_stopping_predictor.predict_raw(validation_datas, batch_size=checkpoint_params.batch_size,
progress_bar=progress_bar, apply_preproc=False)
pred_texts = [d.sentence for d in out]
result = Evaluator.evaluate(gt_data=validation_txts, pred_data=pred_texts, progress_bar=progress_bar)
accuracy = 1 - result["avg_ler"]
if accuracy > early_stopping_best_accuracy:
early_stopping_best_accuracy = accuracy
early_stopping_best_cur_nbest = 1
early_stopping_best_at_iter = iter + 1
# overwrite as best model
last_checkpoint = make_checkpoint(
checkpoint_params.early_stopping_best_model_output_dir,
prefix="",
version=checkpoint_params.early_stopping_best_model_prefix,
)
print("Found better model with accuracy of {:%}".format(early_stopping_best_accuracy))
else:
early_stopping_best_cur_nbest += 1
print("No better model found. Currently accuracy of {:%} at iter {} (remaining nbest = {})".
format(early_stopping_best_accuracy, early_stopping_best_at_iter,
checkpoint_params.early_stopping_nbest - early_stopping_best_cur_nbest))
if accuracy > 0 and early_stopping_best_cur_nbest >= checkpoint_params.early_stopping_nbest:
print("Early stopping now.")
break
except KeyboardInterrupt as e:
print("Storing interrupted checkpoint")
make_checkpoint(checkpoint_params.output_dir,
checkpoint_params.output_model_prefix,
"interrupted")
raise e
print("Total time {}s for {} iterations.".format(time.time() - train_start_time, iter))
def _run_train(self, train_net, test_net, codec, validation_data_params,
train_start_time, progress_bar):
checkpoint_params = self.checkpoint_params
validation_txts = test_net.raw_labels
iters_per_epoch = max(
1, int(len(train_net.raw_images) / checkpoint_params.batch_size))
loss_stats = RunningStatistics(checkpoint_params.stats_size,
checkpoint_params.loss_stats)
ler_stats = RunningStatistics(checkpoint_params.stats_size,
checkpoint_params.ler_stats)
dt_stats = RunningStatistics(checkpoint_params.stats_size,
checkpoint_params.dt_stats)
display = checkpoint_params.display
display_epochs = display <= 1
if display <= 0:
display = 0 # to not display anything
elif display_epochs:
display = max(1,
int(display * iters_per_epoch)) # relative to epochs
else:
display = max(1, int(display)) # iterations
checkpoint_frequency = checkpoint_params.checkpoint_frequency
early_stopping_frequency = checkpoint_params.early_stopping_frequency
if early_stopping_frequency < 0:
# set early stopping frequency to half epoch
early_stopping_frequency = int(0.5 * iters_per_epoch)
elif 0 < early_stopping_frequency <= 1:
early_stopping_frequency = int(
early_stopping_frequency *
iters_per_epoch) # relative to epochs
else:
early_stopping_frequency = int(early_stopping_frequency)
if checkpoint_frequency < 0:
checkpoint_frequency = early_stopping_frequency
elif 0 < checkpoint_frequency <= 1:
checkpoint_frequency = int(checkpoint_frequency *
iters_per_epoch) # relative to epochs
else:
checkpoint_frequency = int(checkpoint_frequency)
early_stopping_enabled = self.validation_dataset is not None \
and checkpoint_params.early_stopping_frequency > 0 \
and checkpoint_params.early_stopping_nbest > 1
early_stopping_best_accuracy = checkpoint_params.early_stopping_best_accuracy
early_stopping_best_cur_nbest = checkpoint_params.early_stopping_best_cur_nbest
early_stopping_best_at_iter = checkpoint_params.early_stopping_best_at_iter
early_stopping_predictor = Predictor(codec=codec,
text_postproc=self.txt_postproc,
network=test_net)
# Start the actual training
# ====================================================================================
iter = checkpoint_params.iter
# helper function to write a checkpoint
def make_checkpoint(base_dir, prefix, version=None):
if version:
checkpoint_path = os.path.abspath(
os.path.join(base_dir, "{}{}.ckpt".format(prefix,
version)))
else:
checkpoint_path = os.path.abspath(
os.path.join(base_dir,
"{}{:08d}.ckpt".format(prefix, iter + 1)))
print("Storing checkpoint to '{}'".format(checkpoint_path))
train_net.save_checkpoint(checkpoint_path)
checkpoint_params.version = Checkpoint.VERSION
checkpoint_params.iter = iter
checkpoint_params.loss_stats[:] = loss_stats.values
checkpoint_params.ler_stats[:] = ler_stats.values
checkpoint_params.dt_stats[:] = dt_stats.values
checkpoint_params.total_time = time.time() - train_start_time
checkpoint_params.early_stopping_best_accuracy = early_stopping_best_accuracy
checkpoint_params.early_stopping_best_cur_nbest = early_stopping_best_cur_nbest
checkpoint_params.early_stopping_best_at_iter = early_stopping_best_at_iter
with open(checkpoint_path + ".json", 'w') as f:
f.write(json_format.MessageToJson(checkpoint_params))
return checkpoint_path
try:
last_checkpoint = None
n_infinite_losses = 0
n_max_infinite_losses = 5
# Training loop, can be interrupted by early stopping
for iter in range(iter, checkpoint_params.max_iters):
checkpoint_params.iter = iter
iter_start_time = time.time()
result = train_net.train_step()
if not np.isfinite(result['loss']):
n_infinite_losses += 1
if n_max_infinite_losses == n_infinite_losses:
print(
"Error: Loss is not finite! Trying to restart from last checkpoint."
)
if not last_checkpoint:
raise Exception(
"No checkpoint written yet. Training must be stopped."
)
else:
# reload also non trainable weights, such as solver-specific variables
train_net.load_weights(
last_checkpoint, restore_only_trainable=False)
continue
else:
continue
n_infinite_losses = 0
loss_stats.push(result['loss'])
ler_stats.push(result['ler'])
dt_stats.push(time.time() - iter_start_time)
if display > 0 and iter % display == 0:
# apply postprocessing to display the true output
pred_sentence = self.txt_postproc.apply("".join(
codec.decode(result["decoded"][0])))
gt_sentence = self.txt_postproc.apply("".join(
codec.decode(result["gt"][0])))
if display_epochs:
print("#{:08f}: loss={:.8f} ler={:.8f} dt={:.8f}s".
format(iter / iters_per_epoch, loss_stats.mean(),
ler_stats.mean(), dt_stats.mean()))
else:
print("#{:08d}: loss={:.8f} ler={:.8f} dt={:.8f}s".
format(iter, loss_stats.mean(), ler_stats.mean(),
dt_stats.mean()))
# Insert utf-8 ltr/rtl direction marks for bidi support
lr = "\u202A\u202B"
print(" PRED: '{}{}{}'".format(
lr[bidi.get_base_level(pred_sentence)], pred_sentence,
"\u202C"))
print(" TRUE: '{}{}{}'".format(
lr[bidi.get_base_level(gt_sentence)], gt_sentence,
"\u202C"))
if checkpoint_frequency > 0 and (
iter + 1) % checkpoint_frequency == 0:
last_checkpoint = make_checkpoint(
checkpoint_params.output_dir,
checkpoint_params.output_model_prefix)
if early_stopping_enabled and (
iter + 1) % early_stopping_frequency == 0:
print("Checking early stopping model")
out = early_stopping_predictor.predict_raw(
validation_data_params,
progress_bar=progress_bar,
apply_preproc=False)
pred_texts = [d.sentence for d in out]
pred_texts = self.txt_preproc.apply(
pred_texts,
processes=checkpoint_params.processes,
progress_bar=progress_bar)
result = Evaluator.evaluate(gt_data=validation_txts,
pred_data=pred_texts,
progress_bar=progress_bar)
accuracy = 1 - result["avg_ler"]
if accuracy > early_stopping_best_accuracy:
early_stopping_best_accuracy = accuracy
early_stopping_best_cur_nbest = 1
early_stopping_best_at_iter = iter + 1
# overwrite as best model
last_checkpoint = make_checkpoint(
checkpoint_params.
early_stopping_best_model_output_dir,
prefix="",
version=checkpoint_params.
early_stopping_best_model_prefix,
)
print(
"Found better model with accuracy of {:%}".format(
early_stopping_best_accuracy))
else:
early_stopping_best_cur_nbest += 1
print(
"No better model found. Currently accuracy of {:%} at iter {} (remaining nbest = {})"
.format(
early_stopping_best_accuracy,
early_stopping_best_at_iter,
checkpoint_params.early_stopping_nbest -
early_stopping_best_cur_nbest))
if accuracy > 0 and early_stopping_best_cur_nbest >= checkpoint_params.early_stopping_nbest:
print("Early stopping now.")
break
if accuracy >= 1:
print(
"Reached perfect score on validation set. Early stopping now."
)
break
except KeyboardInterrupt as e:
print("Storing interrupted checkpoint")
make_checkpoint(checkpoint_params.output_dir,
checkpoint_params.output_model_prefix,
"interrupted")
raise e
print("Total time {}s for {} iterations.".format(
time.time() - train_start_time, iter))