Source code for ignite.contrib.metrics.regression.canberra_metric
from typing import Tuple
import torch
from ignite.contrib.metrics.regression._base import _BaseRegression
from ignite.metrics.metric import reinit__is_reduced, sync_all_reduce
[docs]class CanberraMetric(_BaseRegression):
r"""Calculates the Canberra Metric.
.. math::
\text{CM} = \sum_{j=1}^n\frac{|A_j - P_j|}{|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 `Botchkarev 2018`_ or `scikit-learn distance metrics`_
- ``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)`.
.. _scikit-learn distance metrics:
https://scikit-learn.org/stable/modules/generated/sklearn.metrics.DistanceMetric.html
Parameters are inherited from ``Metric.__init__``.
Args:
output_transform: a callable that is used to transform the
:class:`~ignite.engine.engine.Engine`'s ``process_function``'s output into the
form expected by the metric. This can be useful if, for example, you have a multi-output model and
you want to compute the metric with respect to one of the outputs.
By default, metrics require the output as ``(y_pred, y)`` or ``{'y_pred': y_pred, 'y': y}``.
device: specifies which device updates are accumulated on. Setting the
metric's device to be the same as your ``update`` arguments ensures the ``update`` method is
non-blocking. By default, CPU.
.. _`Botchkarev 2018`:
https://arxiv.org/ftp/arxiv/papers/1809/1809.03006.pdf
Examples:
To use with ``Engine`` and ``process_function``, simply attach the metric instance to the engine.
The output of the engine's ``process_function`` needs to be in format of
``(y_pred, y)`` or ``{'y_pred': y_pred, 'y': y, ...}``.
.. include:: defaults.rst
:start-after: :orphan:
.. testcode::
metric = CanberraMetric()
metric.attach(default_evaluator, 'canberra')
y_pred = torch.tensor([[3.8], [9.9], [-5.4], [2.1]])
y_true = y_pred * 1.5
state = default_evaluator.run([[y_pred, y_true]])
print(state.metrics['canberra'])
.. testoutput::
0.8000...
.. versionchanged:: 0.4.3
- Fixed implementation: ``abs`` in denominator.
- Works with DDP.
"""
[docs] @reinit__is_reduced
def reset(self) -> None:
self._sum_of_errors = torch.tensor(0.0, device=self._device)
def _update(self, output: Tuple[torch.Tensor, torch.Tensor]) -> None:
y_pred, y = output[0].detach(), output[1].detach()
errors = torch.abs(y - y_pred) / (torch.abs(y_pred) + torch.abs(y) + 1e-15)
self._sum_of_errors += torch.sum(errors).to(self._device)
[docs] @sync_all_reduce("_sum_of_errors")
def compute(self) -> float:
return self._sum_of_errors.item()