Add clustering metrics (#3290)

* add silhouette score metric

* add Davies Bouldin score metric

* add Calinski-Harabasz score metric

* small modification on docstring

* update docstring

* remove extra kwargs for calinski_harabasz_score

* simplify imports for sklearn.metrics functions

* add import of ignite.metrics.clustering

* add __all__

* update compute_fn style

* fix type hint

* fix formatting

---------

Co-authored-by: vfdev <vfdev.5@gmail.com>

docs/source/defaults.rst

@@ -12,6 +12,7 @@
         from ignite.engine import *
         from ignite.handlers import *
         from ignite.metrics import *
+        from ignite.metrics.clustering import *
         from ignite.metrics.regression import *
         from ignite.utils import *
 

docs/source/metrics.rst

@@ -382,6 +382,9 @@ Complete list of metrics
     regression.KendallRankCorrelation
     regression.R2Score
     regression.WaveHedgesDistance
+    clustering.SilhouetteScore
+    clustering.DaviesBouldinScore
+    clustering.CalinskiHarabaszScore
 
 
 .. note::

ignite/metrics/__init__.py

@@ -1,3 +1,4 @@
+import ignite.metrics.clustering
 import ignite.metrics.regression
 
 from ignite.metrics.accumulation import Average, GeometricAverage, VariableAccumulation
@@ -82,6 +83,7 @@
     "RougeN",
     "RougeL",
     "regression",
+    "clustering",
     "AveragePrecision",
     "CohenKappa",
     "GpuInfo",

ignite/metrics/clustering/__init__.py

@@ -0,0 +1,3 @@
+from ignite.metrics.clustering.calinski_harabasz_score import CalinskiHarabaszScore
+from ignite.metrics.clustering.davies_bouldin_score import DaviesBouldinScore
+from ignite.metrics.clustering.silhouette_score import SilhouetteScore

ignite/metrics/clustering/_base.py

@@ -0,0 +1,42 @@
+from typing import Tuple
+
+from torch import Tensor
+
+from ignite.exceptions import NotComputableError
+from ignite.metrics.epoch_metric import EpochMetric
+
+
+class _ClusteringMetricBase(EpochMetric):
+    required_output_keys = ("features", "labels")
+
+    def _check_shape(self, output: Tuple[Tensor, Tensor]) -> None:
+        features, labels = output
+        if features.ndimension() != 2:
+            raise ValueError("Features should be of shape (batch_size, n_targets).")
+
+        if labels.ndimension() != 1:
+            raise ValueError("Labels should be of shape (batch_size, ).")
+
+    def _check_type(self, output: Tuple[Tensor, Tensor]) -> None:
+        features, labels = output
+        if len(self._predictions) < 1:
+            return
+        dtype_preds = self._predictions[-1].dtype
+        if dtype_preds != features.dtype:
+            raise ValueError(
+                f"Incoherent types between input features and stored features: {dtype_preds} vs {features.dtype}"
+            )
+
+        dtype_targets = self._targets[-1].dtype
+        if dtype_targets != labels.dtype:
+            raise ValueError(
+                f"Incoherent types between input labels and stored labels: {dtype_targets} vs {labels.dtype}"
+            )
+
+    def compute(self) -> float:
+        if len(self._predictions) < 1 or len(self._targets) < 1:
+            raise NotComputableError(
+                f"{self.__class__.__name__} must have at least one example before it can be computed."
+            )
+
+        return super().compute()

ignite/metrics/clustering/calinski_harabasz_score.py

@@ -0,0 +1,106 @@
+from typing import Any, Callable, Union
+
+import torch
+from torch import Tensor
+
+from ignite.metrics.clustering._base import _ClusteringMetricBase
+
+__all__ = ["CalinskiHarabaszScore"]
+
+
+def _calinski_harabasz_score(features: Tensor, labels: Tensor) -> float:
+    from sklearn.metrics import calinski_harabasz_score
+
+    np_features = features.numpy()
+    np_labels = labels.numpy()
+    score = calinski_harabasz_score(np_features, np_labels)
+    return score
+
+
+class CalinskiHarabaszScore(_ClusteringMetricBase):
+    r"""Calculates the
+    `Calinski-Harabasz score <https://en.wikipedia.org/wiki/Calinski%E2%80%93Harabasz_index>`_.
+
+    The Calinski-Harabasz score evaluates the quality of clustering results.
+
+    More details can be found
+    `here <https://scikit-learn.org/stable/modules/clustering.html#calinski-harabasz-index>`_.
+
+    A higher Calinski-Harabasz score indicates that
+    the clustering result is good (i.e., clusters are well-separated).
+
+    The computation of this metric is implemented with
+    `sklearn.metrics.calinski_harabasz_score
+    <https://scikit-learn.org/stable/modules/generated/sklearn.metrics.calinski_harabasz_score.html>`_.
+
+    - ``update`` must receive output of the form ``(features, labels)``
+      or ``{'features': features, 'labels': labels}``.
+    - `features` and `labels` must be of same shape `(B, D)` and `(B,)`.
+
+    Parameters are inherited from ``EpochMetric.__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 ``(features, labels)``
+            or ``{'features': features, 'labels': labels}``.
+        check_compute_fn: if True, ``compute_fn`` is run on the first batch of data to ensure there are no
+            issues. If issues exist, user is warned that there might be an issue with the ``compute_fn``.
+            Default, True.
+        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.
+        skip_unrolling: specifies whether output should be unrolled before being fed to update method. Should be
+            true for multi-output model, for example, if ``y_pred`` contains multi-ouput as ``(y_pred_a, y_pred_b)``
+            Alternatively, ``output_transform`` can be used to handle this.
+
+    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
+        ``(features, labels)`` or ``{'features': features, 'labels': labels, ...}``.
+
+        .. include:: defaults.rst
+            :start-after: :orphan:
+
+        .. testcode::
+
+            metric = CalinskiHarabaszScore()
+            metric.attach(default_evaluator, "calinski_harabasz_score")
+            X = torch.tensor([
+                    [-1.04, -0.71, -1.42, -0.28, -0.43],
+                    [0.47, 0.96, -0.43, 1.57, -2.24],
+                    [-0.62, -0.29, 0.10, -0.72, -1.69],
+                    [0.96, -0.77, 0.60, -0.89, 0.49],
+                    [-1.33, -1.53, 0.25, -1.60, -2.0],
+                    [-0.63, -0.55, -1.03, -0.89, -0.77],
+                    [-0.26, -1.67, -0.24, -1.33, -0.40],
+                    [-0.20, -1.34, -0.52, -1.55, -1.50],
+                    [2.68, 1.13, 2.51, 0.80, 0.92],
+                    [0.33, 2.88, 1.35, -0.56, 1.71]
+            ])
+            Y = torch.tensor([0, 0, 0, 0, 1, 1, 1, 1, 2, 2])
+            state = default_evaluator.run([{"features": X, "labels": Y}])
+            print(state.metrics["calinski_harabasz_score"])
+
+        .. testoutput::
+
+            5.733935121807529
+
+    .. versionadded:: 0.5.2
+    """
+
+    def __init__(
+        self,
+        output_transform: Callable[..., Any] = lambda x: x,
+        check_compute_fn: bool = True,
+        device: Union[str, torch.device] = torch.device("cpu"),
+        skip_unrolling: bool = False,
+    ) -> None:
+        try:
+            from sklearn.metrics import calinski_harabasz_score  # noqa: F401
+        except ImportError:
+            raise ModuleNotFoundError("This module requires scikit-learn to be installed.")
+
+        super().__init__(_calinski_harabasz_score, output_transform, check_compute_fn, device, skip_unrolling)

ignite/metrics/clustering/davies_bouldin_score.py

@@ -0,0 +1,106 @@
+from typing import Any, Callable, Union
+
+import torch
+from torch import Tensor
+
+from ignite.metrics.clustering._base import _ClusteringMetricBase
+
+__all__ = ["DaviesBouldinScore"]
+
+
+def _davies_bouldin_score(features: Tensor, labels: Tensor) -> float:
+    from sklearn.metrics import davies_bouldin_score
+
+    np_features = features.numpy()
+    np_labels = labels.numpy()
+    score = davies_bouldin_score(np_features, np_labels)
+    return score
+
+
+class DaviesBouldinScore(_ClusteringMetricBase):
+    r"""Calculates the
+    `Davies-Bouldin score <https://en.wikipedia.org/wiki/Davies%E2%80%93Bouldin_index>`_.
+
+    The Davies-Bouldin score evaluates the quality of clustering results.
+
+    More details can be found
+    `here <https://scikit-learn.org/1.5/modules/clustering.html#davies-bouldin-index>`_.
+
+    The Davies-Bouldin score is non-negative,
+    where values closer to zero indicate that the clustering result is good (i.e., clusters are well-separated).
+
+    The computation of this metric is implemented with
+    `sklearn.metrics.davies_bouldin_score
+    <https://scikit-learn.org/1.5/modules/generated/sklearn.metrics.davies_bouldin_score.html>`_.
+
+    - ``update`` must receive output of the form ``(features, labels)``
+      or ``{'features': features, 'labels': labels}``.
+    - `features` and `labels` must be of same shape `(B, D)` and `(B,)`.
+
+    Parameters are inherited from ``EpochMetric.__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 ``(features, labels)``
+            or ``{'features': features, 'labels': labels}``.
+        check_compute_fn: if True, ``compute_fn`` is run on the first batch of data to ensure there are no
+            issues. If issues exist, user is warned that there might be an issue with the ``compute_fn``.
+            Default, True.
+        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.
+        skip_unrolling: specifies whether output should be unrolled before being fed to update method. Should be
+            true for multi-output model, for example, if ``y_pred`` contains multi-ouput as ``(y_pred_a, y_pred_b)``
+            Alternatively, ``output_transform`` can be used to handle this.
+
+    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
+        ``(features, labels)`` or ``{'features': features, 'labels': labels, ...}``.
+
+        .. include:: defaults.rst
+            :start-after: :orphan:
+
+        .. testcode::
+
+            metric = DaviesBouldinScore()
+            metric.attach(default_evaluator, "davies_bouldin_score")
+            X = torch.tensor([
+                    [-1.04, -0.71, -1.42, -0.28, -0.43],
+                    [0.47, 0.96, -0.43, 1.57, -2.24],
+                    [-0.62, -0.29, 0.10, -0.72, -1.69],
+                    [0.96, -0.77, 0.60, -0.89, 0.49],
+                    [-1.33, -1.53, 0.25, -1.60, -2.0],
+                    [-0.63, -0.55, -1.03, -0.89, -0.77],
+                    [-0.26, -1.67, -0.24, -1.33, -0.40],
+                    [-0.20, -1.34, -0.52, -1.55, -1.50],
+                    [2.68, 1.13, 2.51, 0.80, 0.92],
+                    [0.33, 2.88, 1.35, -0.56, 1.71]
+            ])
+            Y = torch.tensor([0, 0, 0, 0, 1, 1, 1, 1, 2, 2])
+            state = default_evaluator.run([{"features": X, "labels": Y}])
+            print(state.metrics["davies_bouldin_score"])
+
+        .. testoutput::
+
+            1.3838673743829881
+
+    .. versionadded:: 0.5.2
+    """
+
+    def __init__(
+        self,
+        output_transform: Callable[..., Any] = lambda x: x,
+        check_compute_fn: bool = True,
+        device: Union[str, torch.device] = torch.device("cpu"),
+        skip_unrolling: bool = False,
+    ) -> None:
+        try:
+            from sklearn.metrics import davies_bouldin_score  # noqa: F401
+        except ImportError:
+            raise ModuleNotFoundError("This module requires scikit-learn to be installed.")
+
+        super().__init__(_davies_bouldin_score, output_transform, check_compute_fn, device, skip_unrolling)