Source code for ignite.contrib.metrics.regression.mean_error
import torch
from ignite.contrib.metrics.regression._base import _BaseRegression
from ignite.exceptions import NotComputableError
[docs]class MeanError(_BaseRegression):
r"""
Calculates the Mean Error:
:math:`\text{ME} = \frac{1}{n}\sum_{j=1}^n (A_j - P_j)`,
where :math:`A_j` is the ground truth and :math:`P_j` is the predicted value.
More details can be found in the reference `Botchkarev 2018`__.
- `update` must receive output of the form `(y_pred, y)` or `{'y_pred': y_pred, 'y': y}`.
- `y` and `y_pred` must be of same shape `(N, )` or `(N, 1)`.
__ https://arxiv.org/abs/1809.03006
"""
def reset(self):
self._sum_of_errors = 0.0
self._num_examples = 0
def _update(self, output):
y_pred, y = output
errors = y.view_as(y_pred) - y_pred
self._sum_of_errors += torch.sum(errors).item()
self._num_examples += y.shape[0]
def compute(self):
if self._num_examples == 0:
raise NotComputableError("MeanError must have at least one example before it can be computed.")
return self._sum_of_errors / self._num_examples