def _get_predictions(self,
data,
break_ties="random",
return_probs=False,
**kwargs):
"""Computes predictions in batch, given a labeled dataset
Args:
data: a Pytorch DataLoader, Dataset, or tuple with Tensors (X,Y):
X: The input for the predict method
Y: An [n] or [n, 1] torch.Tensor or np.ndarray of target labels
in {1,...,k}
break_ties: How to break ties when making predictions
return_probs: Return the predicted probabilities as well
Returns:
Y_p: A Tensor of predictions
Y: A Tensor of labels
[Optionally: Y_s: An [n, k] np.ndarray of predicted probabilities]
"""
data_loader = self._create_data_loader(data)
Y_p = []
Y = []
Y_s = []
# Do batch evaluation by default, getting the predictions and labels
for batch_num, data in enumerate(data_loader):
Xb, Yb = data
Y.append(self._to_numpy(Yb))
# Optionally move to device
if self.config["device"] != "cpu":
Xb = place_on_gpu(Xb)
# Append predictions and labels from DataLoader
Y_pb, Y_sb = self.predict(Xb,
break_ties=break_ties,
return_probs=True,
**kwargs)
Y_p.append(self._to_numpy(Y_pb))
Y_s.append(self._to_numpy(Y_sb))
Y_p, Y, Y_s = map(self._stack_batches, [Y_p, Y, Y_s])
if return_probs:
return Y_p, Y, Y_s
else:
return Y_p, Y
def _train_model(self,
train_data,
loss_fn,
valid_data=None,
log_writer=None,
restore_state={}):
"""The internal training routine called by train_model() after setup
Args:
train_data: a tuple of Tensors (X,Y), a Dataset, or a DataLoader of
X (data) and Y (labels) for the train split
loss_fn: the loss function to minimize (maps *data -> loss)
valid_data: a tuple of Tensors (X,Y), a Dataset, or a DataLoader of
X (data) and Y (labels) for the dev split
restore_state: a dictionary containing model weights (optimizer, main network) and training information
If valid_data is not provided, then no checkpointing or
evaluation on the dev set will occur.
"""
# Set model to train mode
self.train()
train_config = self.config["train_config"]
# Convert data to DataLoaders
train_loader = self._create_data_loader(train_data)
valid_loader = self._create_data_loader(valid_data)
epoch_size = len(train_loader.dataset)
# Move model to GPU
if self.config["verbose"] and self.config["device"] != "cpu":
print("Using GPU...")
self.to(self.config["device"])
# Set training components
self._set_writer(train_config)
self._set_logger(train_config, epoch_size)
self._set_checkpointer(train_config)
self._set_optimizer(train_config)
self._set_scheduler(train_config)
# Restore model if necessary
if restore_state:
start_iteration = self._restore_training_state(restore_state)
else:
start_iteration = 0
# Train the model
metrics_hist = {} # The most recently seen value for all metrics
for epoch in range(start_iteration, train_config["n_epochs"]):
progress_bar = (train_config["progress_bar"]
and self.config["verbose"]
and self.logger.log_unit == "epochs")
t = tqdm(
enumerate(train_loader),
total=len(train_loader),
disable=(not progress_bar),
)
self.running_loss = 0.0
self.running_examples = 0
for batch_num, data in t:
# NOTE: actual batch_size may not equal config's target batch_size
batch_size = len(data[0])
# Moving data to device
if self.config["device"] != "cpu":
data = place_on_gpu(data)
# Zero the parameter gradients
self.optimizer.zero_grad()
# Forward pass to calculate the average loss per example
loss = loss_fn(*data)
if torch.isnan(loss):
msg = "Loss is NaN. Consider reducing learning rate."
raise Exception(msg)
# Backward pass to calculate gradients
# Loss is an average loss per example
loss.backward()
# Perform optimizer step
self.optimizer.step()
# Calculate metrics, log, and checkpoint as necessary
metrics_dict = self._execute_logging(train_loader,
valid_loader, loss,
batch_size)
metrics_hist.update(metrics_dict)
# tqdm output
t.set_postfix(loss=metrics_dict["train/loss"])
# Apply learning rate scheduler
self._update_scheduler(epoch, metrics_hist)
self.eval()
# Restore best model if applicable
if self.checkpointer and self.checkpointer.checkpoint_best:
self.checkpointer.load_best_model(model=self)
# Write log if applicable
if self.writer:
if self.writer.include_config:
self.writer.add_config(self.config)
self.writer.close()
# Print confusion matrix if applicable
if self.config["verbose"]:
print("Finished Training")
if valid_loader is not None:
self.score(
valid_loader,
metric=train_config["validation_metric"],
verbose=True,
print_confusion_matrix=True,
)
def _train_model(self, train_data, loss_fn, dev_data=None, log_writer=None):
"""The internal training routine called by train_model() after setup
Args:
train_data: a tuple of Tensors (X,Y), a Dataset, or a DataLoader of
X (data) and Y (labels) for the train split
loss_fn: the loss function to minimize (maps *data -> loss)
dev_data: a tuple of Tensors (X,Y), a Dataset, or a DataLoader of
X (data) and Y (labels) for the dev split
log_writer: a metal.utils.LogWriter object for logging
If dev_data is not provided, then no checkpointing or
evaluation on the dev set will occur.
"""
train_config = self.config["train_config"]
evaluate_dev = dev_data is not None
# Add config to log_writer if provided
if log_writer is not None:
log_writer.add_config(self.config)
# Convert data to DataLoaders
train_loader = self._create_data_loader(train_data)
dev_loader = self._create_data_loader(dev_data)
# Set the optimizer
optimizer = self._set_optimizer(train_config)
# Set the lr scheduler
scheduler_config = train_config["scheduler_config"]
lr_scheduler = self._set_scheduler(scheduler_config, optimizer)
# Create the checkpointer if applicable
if evaluate_dev and train_config["checkpoint"]:
checkpointer = self._create_checkpointer(
train_config["checkpoint_config"]
)
# Moving model to GPU
if self.config["use_cuda"]:
if self.config["verbose"]:
print("Using GPU...")
self.cuda()
# Train the model
for epoch in range(train_config["n_epochs"]):
epoch_loss = 0.0
t = tqdm(
enumerate(train_loader),
total=len(train_loader),
disable=(
train_config["disable_prog_bar"]
or not self.config["verbose"]
),
)
for batch_num, data in t:
# Moving data to GPU
if self.config["use_cuda"]:
data = place_on_gpu(data)
# Zero the parameter gradients
optimizer.zero_grad()
# Forward pass to calculate outputs
loss = loss_fn(*data)
if torch.isnan(loss):
msg = "Loss is NaN. Consider reducing learning rate."
raise Exception(msg)
# Backward pass to calculate gradients
loss.backward()
# TODO: restore this once it has unit tests
# Clip gradients
# if grad_clip:
# torch.nn.utils.clip_grad_norm(
# self.net.parameters(), grad_clip)
# Perform optimizer step
optimizer.step()
# Keep running sum of losses
epoch_loss += loss.detach()
# tqdm output
running_loss = epoch_loss / (len(data[0]) * (batch_num + 1))
t.set_postfix(avg_loss=float(running_loss))
# Calculate average loss per training example
# Saving division until this stage protects against the potential
# mistake of averaging batch losses when the last batch is an orphan
train_loss = epoch_loss / len(train_loader.dataset)
# Checkpoint performance on dev
if evaluate_dev and (epoch % train_config["validation_freq"] == 0):
val_metric = train_config["validation_metric"]
dev_score = self.score(
dev_loader,
metric=val_metric,
verbose=False,
print_confusion_matrix=False,
)
if train_config["checkpoint"]:
checkpointer.checkpoint(self, epoch, dev_score)
# Apply learning rate scheduler
if (
lr_scheduler is not None
and epoch + 1 >= scheduler_config["lr_freeze"]
):
if scheduler_config["scheduler"] == "reduce_on_plateau":
if evaluate_dev:
lr_scheduler.step(dev_score)
else:
lr_scheduler.step()
# Report progress
if self.config["verbose"] and (
epoch % train_config["print_every"] == 0
or epoch == train_config["n_epochs"] - 1
):
msg = f"[E:{epoch}]\tTrain Loss: {train_loss:.3f}"
if evaluate_dev:
msg += f"\tDev score: {dev_score:.3f}"
print(msg)
# Also write train loss (+ dev score) to log_writer if available
if log_writer is not None and (
epoch % train_config["print_every"] == 0
or epoch == train_config["n_epochs"] - 1
):
tls = float(train_loss.cpu().numpy())
log_writer.add_scalar("train-loss", tls, epoch)
if evaluate_dev:
log_writer.add_scalar("dev-score", dev_score, epoch)
log_writer.write()
# Restore best model if applicable
if evaluate_dev and train_config["checkpoint"]:
checkpointer.restore(model=self)
if log_writer is not None:
log_writer.log["checkpoint_iter"] = checkpointer.best_iteration
# Print confusion matrix if applicable
if self.config["verbose"]:
print("Finished Training")
if evaluate_dev:
self.score(
dev_loader,
metric=["accuracy"],
verbose=True,
print_confusion_matrix=True,
)
# Close log_writer if available
if log_writer is not None:
log_writer.close()
