def get_mean_absolute_error(self, hue: str = DEFAULT_HUE_KEY) -> float:
"""
Get the mean absolute error.
:param hue: The hue to restrict the values used for computation, otherwise all values will be used.
:return: Mean absolute error.
"""
return mean_absolute_error(model_output=self.get_predictions(hue), label=self.get_labels(hue))
def compute_scalar_metrics(metrics_dict: ScalarMetricsDict,
subject_ids: Sequence[str],
model_output: torch.Tensor,
labels: torch.Tensor,
loss_type: ScalarLoss = ScalarLoss.BinaryCrossEntropyWithLogits) -> None:
"""
Computes various metrics for a binary classification task from real-valued model output and a label vector,
and stores them in the given `metrics_dict`.
The model output is assumed to be in the range between 0 and 1, a value larger than 0.5 indicates a prediction
of class 1. The label vector is expected to contain class indices 0 and 1 only.
Metrics for each model output channel will be isolated, and a non-default hue for each model output channel is
expected, and must exist in the provided metrics_dict. The Default hue is used for single model outputs.
:param metrics_dict: An object that holds all metrics. It will be updated in-place.
:param subject_ids: Subject ids for the model output and labels.
:param model_output: A tensor containing model outputs.
:param labels: A tensor containing class labels.
:param loss_type: The type of loss that the model uses. This is required to optionally convert 2-dim model output
to probabilities.
"""
_model_output_channels = model_output.shape[1]
model_output_hues = metrics_dict.get_hue_names(include_default=len(metrics_dict.hues_without_default) == 0)
if len(model_output_hues) < _model_output_channels:
raise ValueError("Hues must be provided for each model output channel, found "
f"{_model_output_channels} channels but only {len(model_output_hues)} hues")
for i, hue in enumerate(model_output_hues):
# mask the model outputs and labels if required
masked_model_outputs_and_labels = get_masked_model_outputs_and_labels(
model_output[:, i, ...], labels[:, i, ...], subject_ids)
# compute metrics on valid masked tensors only
if masked_model_outputs_and_labels is not None:
_model_output, _labels, _subject_ids = \
masked_model_outputs_and_labels.model_outputs.data, \
masked_model_outputs_and_labels.labels.data, \
masked_model_outputs_and_labels.subject_ids
# Convert labels to the same datatype as the model outputs, necessary when running with AMP
_labels = _labels.to(dtype=_model_output.dtype)
if loss_type == ScalarLoss.MeanSquaredError:
metrics = {
MetricType.MEAN_SQUARED_ERROR: F.mse_loss(_model_output, _labels, reduction='mean').item(),
MetricType.MEAN_ABSOLUTE_ERROR: mean_absolute_error(_model_output, _labels),
MetricType.EXPLAINED_VAR: r2_score(_model_output, _labels)
}
else:
metrics = {
MetricType.CROSS_ENTROPY: F.binary_cross_entropy(_model_output, _labels, reduction='mean').item(),
MetricType.ACCURACY_AT_THRESHOLD_05: binary_classification_accuracy(_model_output, _labels)
}
for key, value in metrics.items():
if key == MetricType.EXPLAINED_VAR:
# For a batch size 1, R2 score can be nan. We need to ignore nans
# when average in case the last batch is of size 1.
metrics_dict.add_metric(key, value, skip_nan_when_averaging=True, hue=hue)
else:
metrics_dict.add_metric(key, value, hue=hue)
assert _subject_ids is not None
metrics_dict.add_predictions(_subject_ids, _model_output.detach().cpu().numpy(),
_labels.cpu().numpy(), hue=hue)