def get_metrics(model: Model,
total_loss: float,
num_batches: int,
reset: bool = False) -> Dict[str, float]:
"""
Gets the metrics but sets ``"loss"`` to
the total loss divided by the ``num_batches`` so that
the ``"loss"`` metric is "average loss per batch".
"""
metrics = model.get_metrics(reset=reset)
metrics["loss"] = float(total_loss /
num_batches) if num_batches > 0 else 0.0
return metrics
def evaluate(model: Model, instances: Iterable[Instance],
data_iterator: DataIterator, cuda_device: int,
batch_weight_key: str) -> Dict[str, Any]:
check_for_gpu(cuda_device)
with torch.no_grad():
model.eval()
iterator = data_iterator(instances, num_epochs=1, shuffle=False)
logger.info("Iterating over dataset")
generator_tqdm = Tqdm.tqdm(
iterator, total=data_iterator.get_num_batches(instances))
# Number of batches in instances.
batch_count = 0
# Number of batches where the model produces a loss.
loss_count = 0
# Cumulative weighted loss
total_loss = 0.0
# Cumulative weight across all batches.
total_weight = 0.0
for batch in generator_tqdm:
batch_count += 1
batch = nn_util.move_to_device(batch, cuda_device)
output_dict = model(**batch)
loss = output_dict.get("loss")
metrics = model.get_metrics()
if loss is not None:
loss_count += 1
if batch_weight_key:
weight = output_dict[batch_weight_key].item()
else:
weight = 1.0
total_weight += weight
total_loss += loss.item() * weight
# Report the average loss so far.
metrics["loss"] = total_loss / total_weight
if (not HasBeenWarned.tqdm_ignores_underscores and any(
metric_name.startswith("_") for metric_name in metrics)):
logger.warning("Metrics with names beginning with \"_\" will "
"not be logged to the tqdm progress bar.")
HasBeenWarned.tqdm_ignores_underscores = True
description = ', '.join([
"%s: %.2f" % (name, value)
for name, value in metrics.items() if not name.startswith("_")
]) + " ||"
generator_tqdm.set_description(description, refresh=False)
final_metrics = model.get_metrics(reset=True)
if loss_count > 0:
# Sanity check
if loss_count != batch_count:
raise RuntimeError(
"The model you are trying to evaluate only sometimes " +
"produced a loss!")
final_metrics["loss"] = total_loss / total_weight
return final_metrics