From 85310c13d9d7276c7170be0527812e22da83492d Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Mon, 15 Mar 2021 20:29:46 +0100
Subject: [PATCH 01/11] docs

---
 pytorch_lightning/metrics/compositional.py |  7 ++--
 pytorch_lightning/metrics/metric.py        | 12 +++----
 pytorch_lightning/metrics/utils.py         | 40 ++++++++++------------
 3 files changed, 26 insertions(+), 33 deletions(-)

diff --git a/pytorch_lightning/metrics/compositional.py b/pytorch_lightning/metrics/compositional.py
index 5961714209d40..baa631bbeb25d 100644
--- a/pytorch_lightning/metrics/compositional.py
+++ b/pytorch_lightning/metrics/compositional.py
@@ -21,10 +21,9 @@
 
 
 class CompositionalMetric(__CompositionalMetric):
-    r"""
-    This implementation refers to :class:`~torchmetrics.metric.CompositionalMetric`.
-
-    .. warning:: This metric is deprecated, use ``torchmetrics.metric.CompositionalMetric``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :class:`torchmetrics.metric.CompositionalMetric`. Will be removed in v1.5.0.
     """
 
     def __init__(
diff --git a/pytorch_lightning/metrics/metric.py b/pytorch_lightning/metrics/metric.py
index 145a13a251250..f856cb39e3da4 100644
--- a/pytorch_lightning/metrics/metric.py
+++ b/pytorch_lightning/metrics/metric.py
@@ -21,9 +21,8 @@
 
 class Metric(__Metric):
     r"""
-    This implementation refers to :class:`~torchmetrics.Metric`.
-
-    .. warning:: This metric is deprecated, use ``torchmetrics.Metric``. Will be removed in v1.5.0.
+    .. deprecated::
+        Use :class:`torchmetrics.Metric`. Will be removed in v1.5.0.
     """
 
     def __init__(
@@ -46,10 +45,9 @@ def __init__(
 
 
 class MetricCollection(__MetricCollection):
-    r"""
-    This implementation refers to :class:`~torchmetrics.MetricCollection`.
-
-    .. warning:: This metric is deprecated, use ``torchmetrics.MetricCollection``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :class:`torchmetrics.MetricCollection`. Will be removed in v1.5.0.
     """
 
     def __init__(self, metrics: Union[List[Metric], Tuple[Metric], Dict[str, Metric]]):
diff --git a/pytorch_lightning/metrics/utils.py b/pytorch_lightning/metrics/utils.py
index 63c6892cb2987..e751e30dc1284 100644
--- a/pytorch_lightning/metrics/utils.py
+++ b/pytorch_lightning/metrics/utils.py
@@ -78,8 +78,9 @@ def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
 
 
 def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) -> torch.Tensor:
-    r"""
-    .. warning:: This function is deprecated, use ``torchmetrics.utilities.data.to_onehot``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.data.to_onehot`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `to_onehot` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.to_onehot`."
@@ -89,10 +90,9 @@ def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) ->
 
 
 def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch.Tensor:
-    r"""
-    .. warning::
-
-        This function is deprecated, use ``torchmetrics.utilities.data.select_topk``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.data.select_topk`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `select_topk` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.select_topk`."
@@ -102,10 +102,9 @@ def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch
 
 
 def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
-    r"""
-    .. warning::
-
-        This function is deprecated, use ``torchmetrics.utilities.data.to_categorical``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.data.to_categorical`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `to_categorical` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.to_categorical`."
@@ -115,10 +114,9 @@ def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
 
 
 def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optional[int] = None) -> int:
-    r"""
-    .. warning::
-
-        This function is deprecated, use ``torchmetrics.utilities.data.get_num_classes``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.data.get_num_classes`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `get_num_classes` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.get_num_classes`."
@@ -128,10 +126,9 @@ def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optio
 
 
 def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
-    r"""
-    .. warning::
-
-        This function is deprecated, use ``torchmetrics.utilities.reduce``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.reduce`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `reduce` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.reduce`."
@@ -143,10 +140,9 @@ def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
 def class_reduce(
     num: torch.Tensor, denom: torch.Tensor, weights: torch.Tensor, class_reduction: str = "none"
 ) -> torch.Tensor:
-    r"""
-    .. warning::
-
-        This function is deprecated, use ``torchmetrics.utilities.class_reduce``. Will be removed in v1.5.0.
+    """
+    .. deprecated::
+        Use :func:`torchmetrics.utilities.class_reduce`. Will be removed in v1.5.0.
     """
     rank_zero_warn(
         "This `class_reduce` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.class_reduce`."

From 069128261a21f1e25e7e19bb7110e213e1e81cb2 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 00:34:24 +0100
Subject: [PATCH 02/11] wrapper

---
 pytorch_lightning/metrics/utils.py         | 56 +++++---------------
 pytorch_lightning/utilities/deprecation.py | 61 ++++++++++++++++++++++
 tests/utilities/test_deprecation.py        | 20 +++++++
 3 files changed, 94 insertions(+), 43 deletions(-)
 create mode 100644 pytorch_lightning/utilities/deprecation.py
 create mode 100644 tests/utilities/test_deprecation.py

diff --git a/pytorch_lightning/metrics/utils.py b/pytorch_lightning/metrics/utils.py
index e751e30dc1284..e5ec25a9ad556 100644
--- a/pytorch_lightning/metrics/utils.py
+++ b/pytorch_lightning/metrics/utils.py
@@ -24,28 +24,22 @@
 from torchmetrics.utilities.distributed import class_reduce as __class_reduce
 from torchmetrics.utilities.distributed import reduce as __reduce
 
-from pytorch_lightning.utilities import rank_zero_warn
+from pytorch_lightning.utilities.deprecation import deprecated_func
 
 
+@deprecated_func(target_func=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_cat(x):
-    rank_zero_warn(
-        "This `dim_zero_cat` was deprecated since v1.3.0 and it will be removed in v1.5.0", DeprecationWarning
-    )
-    return __dim_zero_cat(x)
+    pass
 
 
+@deprecated_func(target_func=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_sum(x):
-    rank_zero_warn(
-        "This `dim_zero_sum` was deprecated since v1.3.0 and it will be removed in v1.5.0", DeprecationWarning
-    )
-    return __dim_zero_sum(x)
+    pass
 
 
+@deprecated_func(target_func=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_mean(x):
-    rank_zero_warn(
-        "This `dim_zero_mean` was deprecated since v1.3.0 and it will be removed in v1.5.0", DeprecationWarning
-    )
-    return __dim_zero_mean(x)
+    pass
 
 
 def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
@@ -77,66 +71,47 @@ def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
     return [torch.tensor(x, dtype=torch.int64) for x in indexes.values()]
 
 
+@deprecated_func(target_func=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) -> torch.Tensor:
     """
     .. deprecated::
         Use :func:`torchmetrics.utilities.data.to_onehot`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `to_onehot` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.to_onehot`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __to_onehot(label_tensor=label_tensor, num_classes=num_classes)
 
 
+@deprecated_func(target_func=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
         Use :func:`torchmetrics.utilities.data.select_topk`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `select_topk` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.select_topk`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __select_topk(prob_tensor=prob_tensor, topk=topk, dim=dim)
 
 
+@deprecated_func(target_func=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
         Use :func:`torchmetrics.utilities.data.to_categorical`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `to_categorical` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.to_categorical`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __to_categorical(tensor=tensor, argmax_dim=argmax_dim)
 
 
+@deprecated_func(target_func=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optional[int] = None) -> int:
     """
     .. deprecated::
         Use :func:`torchmetrics.utilities.data.get_num_classes`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `get_num_classes` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.data.get_num_classes`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __get_num_classes(pred=pred, target=target, num_classes=num_classes)
 
 
+@deprecated_func(target_func=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
     .. deprecated::
         Use :func:`torchmetrics.utilities.reduce`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `reduce` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.reduce`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __reduce(to_reduce=to_reduce, reduction=reduction)
 
 
+@deprecated_func(target_func=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def class_reduce(
     num: torch.Tensor, denom: torch.Tensor, weights: torch.Tensor, class_reduction: str = "none"
 ) -> torch.Tensor:
@@ -144,8 +119,3 @@ def class_reduce(
     .. deprecated::
         Use :func:`torchmetrics.utilities.class_reduce`. Will be removed in v1.5.0.
     """
-    rank_zero_warn(
-        "This `class_reduce` was deprecated since v1.3.0 in favor of `torchmetrics.utilities.class_reduce`."
-        " It will be removed in v1.5.0", DeprecationWarning
-    )
-    return __class_reduce(num=num, denom=denom, weights=weights, class_reduction=class_reduction)
diff --git a/pytorch_lightning/utilities/deprecation.py b/pytorch_lightning/utilities/deprecation.py
new file mode 100644
index 0000000000000..336d833e229cd
--- /dev/null
+++ b/pytorch_lightning/utilities/deprecation.py
@@ -0,0 +1,61 @@
+# Copyright The PyTorch Lightning team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import inspect
+from functools import wraps
+from typing import Any, Callable, List, Tuple
+
+from pytorch_lightning.utilities import rank_zero_warn
+
+
+def get_func_arguments_and_types(func: Callable) -> List[Tuple[str, Tuple, Any]]:
+    """Parse function arguments, types and default values
+
+    Example:
+        >>> get_func_arguments_and_types(get_func_arguments_and_types)
+        [('func', typing.Callable, <class 'inspect._empty'>)]
+    """
+    func_default_params = inspect.signature(func).parameters
+    name_type_default = []
+    for arg in func_default_params:
+        arg_type = func_default_params[arg].annotation
+        arg_default = func_default_params[arg].default
+        name_type_default.append((arg, arg_type, arg_default))
+    return name_type_default
+
+
+def deprecated_func(target_func: Callable, ver_deprecate: str = "", ver_remove: str = "") -> Callable:
+
+    def inner_function(func):
+
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            target_func_str = f'{target_func.__module__}.{target_func.__name__}'
+            rank_zero_warn(
+                f"This `{func.__name__}` was deprecated since v{ver_deprecate} in favor of `{target_func_str}`."
+                f" It will be removed in v{ver_remove}.", DeprecationWarning
+            )
+            if args:  # in case any args passed move them to kwargs
+                # parse only the argument names
+                cls_arg_names = [arg[0] for arg in get_func_arguments_and_types(func)]
+                # convert args to kwargs
+                kwargs.update({k: v for k, v in zip(cls_arg_names, args)})
+            target_args = [arg[0] for arg in get_func_arguments_and_types(target_func)]
+            assert all(arg in target_args for arg in kwargs), \
+                "Failed mapping, arguments missing in target func: %s" % [arg not in target_args for arg in kwargs]
+            # all args were already moved to kwargs
+            return target_func(**kwargs)
+
+        return wrapper
+
+    return inner_function
diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
new file mode 100644
index 0000000000000..730838686a060
--- /dev/null
+++ b/tests/utilities/test_deprecation.py
@@ -0,0 +1,20 @@
+import pytest
+
+from pytorch_lightning.utilities.deprecation import deprecated_func
+
+
+def my_sum(a, b=3):
+    return a + b
+
+
+@deprecated_func(target_func=my_sum, ver_deprecate="0.1", ver_remove="0.5")
+def dep_sum(a, b):
+    pass
+
+
+def test_deprecated_func():
+    with pytest.deprecated_call(
+        match='This `dep_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
+        ' It will be removed in v0.5.'
+    ):
+        assert dep_sum(2, b=5) == 7

From cab6e224b7eb250b212e7ee2004760237b6ccc7c Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 00:44:13 +0100
Subject: [PATCH 03/11] test

---
 pytorch_lightning/metrics/compositional.py      |  4 ++--
 tests/deprecated_api/test_remove_1-5_metrics.py | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/pytorch_lightning/metrics/compositional.py b/pytorch_lightning/metrics/compositional.py
index baa631bbeb25d..975b8280f77d5 100644
--- a/pytorch_lightning/metrics/compositional.py
+++ b/pytorch_lightning/metrics/compositional.py
@@ -33,7 +33,7 @@ def __init__(
         metric_b: Union[Metric, int, float, torch.Tensor, None],
     ):
         rank_zero_warn(
-            "This `Metric` was deprecated since v1.3.0 in favor of `torchmetrics.Metric`."
-            " It will be removed in v1.5.0", DeprecationWarning
+            "This `CompositionalMetric` was deprecated since v1.3.0 in favor of"
+            " `torchmetrics.metric.CompositionalMetric`. It will be removed in v1.5.0", DeprecationWarning
         )
         super().__init__(operator=operator, metric_a=metric_a, metric_b=metric_b)
diff --git a/tests/deprecated_api/test_remove_1-5_metrics.py b/tests/deprecated_api/test_remove_1-5_metrics.py
index b2fa4f69f74b9..fcbeaa2e78819 100644
--- a/tests/deprecated_api/test_remove_1-5_metrics.py
+++ b/tests/deprecated_api/test_remove_1-5_metrics.py
@@ -18,6 +18,8 @@
 
 from pytorch_lightning.metrics.utils import get_num_classes, select_topk, to_categorical, to_onehot
 
+from pytorch_lightning.metrics import MetricCollection, Accuracy
+
 
 def test_v1_5_0_metrics_utils():
     x = torch.tensor([1, 2, 3])
@@ -34,3 +36,14 @@ def test_v1_5_0_metrics_utils():
     x = torch.tensor([[0.2, 0.5], [0.9, 0.1]])
     with pytest.deprecated_call(match="It will be removed in v1.5.0"):
         assert torch.equal(to_categorical(x), torch.Tensor([1, 0]).to(int))
+
+
+def test_v1_5_0_metrics_collection():
+    target = torch.tensor([0, 2, 0, 2, 0, 1, 0, 2])
+    preds = torch.tensor([2, 1, 2, 0, 1, 2, 2, 2])
+    with pytest.deprecated_call(
+            match="This `MetricCollection` was deprecated since v1.3.0 in favor of `torchmetrics.MetricCollection`."
+                  " It will be removed in v1.5.0"
+    ):
+        metrics = MetricCollection([Accuracy()])
+    assert metrics(preds, target) == {'Accuracy': torch.Tensor([0.1250])[0]}

From 9b66f5c3c5328792e770e1b368b1464ccab392f1 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 10:07:10 +0100
Subject: [PATCH 04/11] test

---
 pytorch_lightning/core/step_result.py         |  2 +-
 .../metrics/classification/accuracy.py        |  2 +-
 .../metrics/classification/auc.py             |  2 +-
 .../metrics/classification/auroc.py           |  2 +-
 .../classification/average_precision.py       |  2 +-
 .../classification/confusion_matrix.py        |  2 +-
 .../metrics/classification/f_beta.py          |  2 +-
 .../classification/hamming_distance.py        |  2 +-
 .../classification/precision_recall_curve.py  |  2 +-
 .../metrics/classification/roc.py             |  2 +-
 .../metrics/classification/stat_scores.py     |  2 +-
 pytorch_lightning/metrics/metric.py           | 16 +++++++--------
 .../metrics/regression/explained_variance.py  |  2 +-
 .../metrics/regression/mean_absolute_error.py |  2 +-
 .../metrics/regression/mean_squared_error.py  |  2 +-
 .../regression/mean_squared_log_error.py      |  2 +-
 pytorch_lightning/metrics/regression/psnr.py  |  2 +-
 .../metrics/regression/r2score.py             |  2 +-
 pytorch_lightning/metrics/regression/ssim.py  |  2 +-
 .../metrics/retrieval/retrieval_metric.py     |  2 +-
 pytorch_lightning/metrics/utils.py            | 20 +++++++++----------
 .../logger_connector/metrics_holder.py        |  3 +--
 pytorch_lightning/utilities/deprecation.py    | 15 +++++++++++---
 tests/core/test_metric_result_integration.py  |  2 +-
 .../deprecated_api/test_remove_1-5_metrics.py |  7 +++----
 .../classification/test_precision_recall.py   |  3 ++-
 tests/metrics/retrieval/test_map.py           |  2 +-
 tests/metrics/test_metric_lightning.py        |  2 +-
 tests/metrics/utils.py                        |  3 +--
 tests/utilities/test_deprecation.py           |  4 ++--
 30 files changed, 60 insertions(+), 55 deletions(-)

diff --git a/pytorch_lightning/core/step_result.py b/pytorch_lightning/core/step_result.py
index f8d7a2ffe3a23..3961586f4946a 100644
--- a/pytorch_lightning/core/step_result.py
+++ b/pytorch_lightning/core/step_result.py
@@ -20,8 +20,8 @@
 
 import torch
 from torch import Tensor
+from torchmetrics import Metric
 
-from pytorch_lightning.metrics import Metric
 from pytorch_lightning.utilities.distributed import sync_ddp_if_available
 
 
diff --git a/pytorch_lightning/metrics/classification/accuracy.py b/pytorch_lightning/metrics/classification/accuracy.py
index 343e979dd3e0c..367c9b029d841 100644
--- a/pytorch_lightning/metrics/classification/accuracy.py
+++ b/pytorch_lightning/metrics/classification/accuracy.py
@@ -14,9 +14,9 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.accuracy import _accuracy_compute, _accuracy_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class Accuracy(Metric):
diff --git a/pytorch_lightning/metrics/classification/auc.py b/pytorch_lightning/metrics/classification/auc.py
index 6c5a29173d20a..76c1959a8603a 100644
--- a/pytorch_lightning/metrics/classification/auc.py
+++ b/pytorch_lightning/metrics/classification/auc.py
@@ -14,9 +14,9 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.auc import _auc_compute, _auc_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/auroc.py b/pytorch_lightning/metrics/classification/auroc.py
index 6b9b5ae9f021f..7d8ba7368e45d 100644
--- a/pytorch_lightning/metrics/classification/auroc.py
+++ b/pytorch_lightning/metrics/classification/auroc.py
@@ -15,9 +15,9 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.auroc import _auroc_compute, _auroc_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/average_precision.py b/pytorch_lightning/metrics/classification/average_precision.py
index f9c7bde158383..adcdd86ed1ca8 100644
--- a/pytorch_lightning/metrics/classification/average_precision.py
+++ b/pytorch_lightning/metrics/classification/average_precision.py
@@ -14,9 +14,9 @@
 from typing import Any, List, Optional, Union
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.average_precision import _average_precision_compute, _average_precision_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/confusion_matrix.py b/pytorch_lightning/metrics/classification/confusion_matrix.py
index c3defc82bc92d..112fb4940e6e2 100644
--- a/pytorch_lightning/metrics/classification/confusion_matrix.py
+++ b/pytorch_lightning/metrics/classification/confusion_matrix.py
@@ -14,9 +14,9 @@
 from typing import Any, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.confusion_matrix import _confusion_matrix_compute, _confusion_matrix_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class ConfusionMatrix(Metric):
diff --git a/pytorch_lightning/metrics/classification/f_beta.py b/pytorch_lightning/metrics/classification/f_beta.py
index ae01b80966868..a46b01a1aa8b7 100644
--- a/pytorch_lightning/metrics/classification/f_beta.py
+++ b/pytorch_lightning/metrics/classification/f_beta.py
@@ -14,9 +14,9 @@
 from typing import Any, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.f_beta import _fbeta_compute, _fbeta_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/hamming_distance.py b/pytorch_lightning/metrics/classification/hamming_distance.py
index adf1086f3c85f..dceb90c0a4ca9 100644
--- a/pytorch_lightning/metrics/classification/hamming_distance.py
+++ b/pytorch_lightning/metrics/classification/hamming_distance.py
@@ -14,9 +14,9 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.hamming_distance import _hamming_distance_compute, _hamming_distance_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class HammingDistance(Metric):
diff --git a/pytorch_lightning/metrics/classification/precision_recall_curve.py b/pytorch_lightning/metrics/classification/precision_recall_curve.py
index 5a02a99ed17fd..ccf821d829d78 100644
--- a/pytorch_lightning/metrics/classification/precision_recall_curve.py
+++ b/pytorch_lightning/metrics/classification/precision_recall_curve.py
@@ -14,12 +14,12 @@
 from typing import Any, List, Optional, Tuple, Union
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.precision_recall_curve import (
     _precision_recall_curve_compute,
     _precision_recall_curve_update,
 )
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/roc.py b/pytorch_lightning/metrics/classification/roc.py
index 598646cde3861..30ca0b4fe6925 100644
--- a/pytorch_lightning/metrics/classification/roc.py
+++ b/pytorch_lightning/metrics/classification/roc.py
@@ -14,9 +14,9 @@
 from typing import Any, List, Optional, Tuple, Union
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.roc import _roc_compute, _roc_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/classification/stat_scores.py b/pytorch_lightning/metrics/classification/stat_scores.py
index 3807d7079b508..672b0f41c6fc5 100644
--- a/pytorch_lightning/metrics/classification/stat_scores.py
+++ b/pytorch_lightning/metrics/classification/stat_scores.py
@@ -14,9 +14,9 @@
 from typing import Any, Callable, Optional, Tuple
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.stat_scores import _stat_scores_compute, _stat_scores_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class StatScores(Metric):
diff --git a/pytorch_lightning/metrics/metric.py b/pytorch_lightning/metrics/metric.py
index f856cb39e3da4..d4d621b158303 100644
--- a/pytorch_lightning/metrics/metric.py
+++ b/pytorch_lightning/metrics/metric.py
@@ -13,13 +13,14 @@
 # limitations under the License.
 from typing import Any, Callable, Dict, List, Optional, Tuple, Union
 
-from torchmetrics import Metric as __Metric
-from torchmetrics import MetricCollection as __MetricCollection
+from torchmetrics import Metric as _Metric
+from torchmetrics.collections import MetricCollection as _MetricCollection
 
+from pytorch_lightning.utilities.deprecation import _deprecated
 from pytorch_lightning.utilities.distributed import rank_zero_warn
 
 
-class Metric(__Metric):
+class Metric(_Metric):
     r"""
     .. deprecated::
         Use :class:`torchmetrics.Metric`. Will be removed in v1.5.0.
@@ -44,15 +45,12 @@ def __init__(
         )
 
 
-class MetricCollection(__MetricCollection):
+class MetricCollection(_MetricCollection):
     """
     .. deprecated::
         Use :class:`torchmetrics.MetricCollection`. Will be removed in v1.5.0.
     """
 
+    @_deprecated(target=_MetricCollection, ver_deprecate="1.3.0", ver_remove="1.5.0")
     def __init__(self, metrics: Union[List[Metric], Tuple[Metric], Dict[str, Metric]]):
-        rank_zero_warn(
-            "This `MetricCollection` was deprecated since v1.3.0 in favor of `torchmetrics.MetricCollection`."
-            " It will be removed in v1.5.0", DeprecationWarning
-        )
-        super().__init__(metrics=metrics)
+        pass
diff --git a/pytorch_lightning/metrics/regression/explained_variance.py b/pytorch_lightning/metrics/regression/explained_variance.py
index fc033fcd16759..8b0259694ef4c 100644
--- a/pytorch_lightning/metrics/regression/explained_variance.py
+++ b/pytorch_lightning/metrics/regression/explained_variance.py
@@ -14,12 +14,12 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.explained_variance import (
     _explained_variance_compute,
     _explained_variance_update,
 )
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/regression/mean_absolute_error.py b/pytorch_lightning/metrics/regression/mean_absolute_error.py
index ca184daf736b8..484ccbe83284e 100644
--- a/pytorch_lightning/metrics/regression/mean_absolute_error.py
+++ b/pytorch_lightning/metrics/regression/mean_absolute_error.py
@@ -14,12 +14,12 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.mean_absolute_error import (
     _mean_absolute_error_compute,
     _mean_absolute_error_update,
 )
-from pytorch_lightning.metrics.metric import Metric
 
 
 class MeanAbsoluteError(Metric):
diff --git a/pytorch_lightning/metrics/regression/mean_squared_error.py b/pytorch_lightning/metrics/regression/mean_squared_error.py
index 09f275ded8638..c26371514e7cd 100644
--- a/pytorch_lightning/metrics/regression/mean_squared_error.py
+++ b/pytorch_lightning/metrics/regression/mean_squared_error.py
@@ -14,12 +14,12 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.mean_squared_error import (
     _mean_squared_error_compute,
     _mean_squared_error_update,
 )
-from pytorch_lightning.metrics.metric import Metric
 
 
 class MeanSquaredError(Metric):
diff --git a/pytorch_lightning/metrics/regression/mean_squared_log_error.py b/pytorch_lightning/metrics/regression/mean_squared_log_error.py
index 18105e687b0b1..caaf09a3663ff 100644
--- a/pytorch_lightning/metrics/regression/mean_squared_log_error.py
+++ b/pytorch_lightning/metrics/regression/mean_squared_log_error.py
@@ -14,12 +14,12 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.mean_squared_log_error import (
     _mean_squared_log_error_compute,
     _mean_squared_log_error_update,
 )
-from pytorch_lightning.metrics.metric import Metric
 
 
 class MeanSquaredLogError(Metric):
diff --git a/pytorch_lightning/metrics/regression/psnr.py b/pytorch_lightning/metrics/regression/psnr.py
index 8a38bf515ebca..746ff1e52d574 100644
--- a/pytorch_lightning/metrics/regression/psnr.py
+++ b/pytorch_lightning/metrics/regression/psnr.py
@@ -14,10 +14,10 @@
 from typing import Any, Optional, Sequence, Tuple, Union
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning import utilities
 from pytorch_lightning.metrics.functional.psnr import _psnr_compute, _psnr_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class PSNR(Metric):
diff --git a/pytorch_lightning/metrics/regression/r2score.py b/pytorch_lightning/metrics/regression/r2score.py
index 40d9d24711375..8156b8bc72d48 100644
--- a/pytorch_lightning/metrics/regression/r2score.py
+++ b/pytorch_lightning/metrics/regression/r2score.py
@@ -14,9 +14,9 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.r2score import _r2score_compute, _r2score_update
-from pytorch_lightning.metrics.metric import Metric
 
 
 class R2Score(Metric):
diff --git a/pytorch_lightning/metrics/regression/ssim.py b/pytorch_lightning/metrics/regression/ssim.py
index 09b55fb2bb456..a3bbab938ffad 100644
--- a/pytorch_lightning/metrics/regression/ssim.py
+++ b/pytorch_lightning/metrics/regression/ssim.py
@@ -14,9 +14,9 @@
 from typing import Any, Optional, Sequence
 
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning.metrics.functional.ssim import _ssim_compute, _ssim_update
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.utilities import rank_zero_warn
 
 
diff --git a/pytorch_lightning/metrics/retrieval/retrieval_metric.py b/pytorch_lightning/metrics/retrieval/retrieval_metric.py
index 29f02555dad69..6f9088d00083c 100644
--- a/pytorch_lightning/metrics/retrieval/retrieval_metric.py
+++ b/pytorch_lightning/metrics/retrieval/retrieval_metric.py
@@ -2,8 +2,8 @@
 from typing import Any, Callable, Optional
 
 import torch
+from torchmetrics import Metric
 
-from pytorch_lightning.metrics import Metric
 from pytorch_lightning.metrics.utils import get_group_indexes
 
 #: get_group_indexes is used to group predictions belonging to the same query
diff --git a/pytorch_lightning/metrics/utils.py b/pytorch_lightning/metrics/utils.py
index e5ec25a9ad556..5cbb8a877948a 100644
--- a/pytorch_lightning/metrics/utils.py
+++ b/pytorch_lightning/metrics/utils.py
@@ -24,20 +24,20 @@
 from torchmetrics.utilities.distributed import class_reduce as __class_reduce
 from torchmetrics.utilities.distributed import reduce as __reduce
 
-from pytorch_lightning.utilities.deprecation import deprecated_func
+from pytorch_lightning.utilities.deprecation import _deprecated
 
 
-@deprecated_func(target_func=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_cat(x):
     pass
 
 
-@deprecated_func(target_func=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_sum(x):
     pass
 
 
-@deprecated_func(target_func=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_mean(x):
     pass
 
@@ -71,7 +71,7 @@ def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
     return [torch.tensor(x, dtype=torch.int64) for x in indexes.values()]
 
 
-@deprecated_func(target_func=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) -> torch.Tensor:
     """
     .. deprecated::
@@ -79,7 +79,7 @@ def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) ->
     """
 
 
-@deprecated_func(target_func=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -87,7 +87,7 @@ def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch
     """
 
 
-@deprecated_func(target_func=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -95,7 +95,7 @@ def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
 
 
-@deprecated_func(target_func=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optional[int] = None) -> int:
     """
     .. deprecated::
@@ -103,7 +103,7 @@ def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optio
     """
 
 
-@deprecated_func(target_func=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
     .. deprecated::
@@ -111,7 +111,7 @@ def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
 
 
-@deprecated_func(target_func=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@_deprecated(target=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def class_reduce(
     num: torch.Tensor, denom: torch.Tensor, weights: torch.Tensor, class_reduction: str = "none"
 ) -> torch.Tensor:
diff --git a/pytorch_lightning/trainer/connectors/logger_connector/metrics_holder.py b/pytorch_lightning/trainer/connectors/logger_connector/metrics_holder.py
index 82f328a927485..554f1d3faf9ed 100644
--- a/pytorch_lightning/trainer/connectors/logger_connector/metrics_holder.py
+++ b/pytorch_lightning/trainer/connectors/logger_connector/metrics_holder.py
@@ -15,8 +15,7 @@
 from typing import Any
 
 import torch
-
-from pytorch_lightning.metrics.metric import Metric
+from torchmetrics import Metric
 
 
 class MetricsHolder:
diff --git a/pytorch_lightning/utilities/deprecation.py b/pytorch_lightning/utilities/deprecation.py
index 336d833e229cd..ba0d0483ee8bb 100644
--- a/pytorch_lightning/utilities/deprecation.py
+++ b/pytorch_lightning/utilities/deprecation.py
@@ -34,22 +34,31 @@ def get_func_arguments_and_types(func: Callable) -> List[Tuple[str, Tuple, Any]]
     return name_type_default
 
 
-def deprecated_func(target_func: Callable, ver_deprecate: str = "", ver_remove: str = "") -> Callable:
+def _deprecated(target: Callable, ver_deprecate: str = "", ver_remove: str = "") -> Callable:
+    """
+    Decorate a function or class ``__init__`` with warning message
+     and pass all arguments directly to the target class/method.
+     """
 
     def inner_function(func):
 
         @wraps(func)
         def wrapper(*args, **kwargs):
-            target_func_str = f'{target_func.__module__}.{target_func.__name__}'
+            is_class = inspect.isclass(target)
+            target_func = target.__init__ if is_class else target
+            target_str = f'{target.__module__}.{target.__name__}'
+            func_name = func.__qualname__.split('.')[-2] if is_class else func.__name__
             rank_zero_warn(
-                f"This `{func.__name__}` was deprecated since v{ver_deprecate} in favor of `{target_func_str}`."
+                f"This `{func_name}` was deprecated since v{ver_deprecate} in favor of `{target_str}`."
                 f" It will be removed in v{ver_remove}.", DeprecationWarning
             )
+
             if args:  # in case any args passed move them to kwargs
                 # parse only the argument names
                 cls_arg_names = [arg[0] for arg in get_func_arguments_and_types(func)]
                 # convert args to kwargs
                 kwargs.update({k: v for k, v in zip(cls_arg_names, args)})
+
             target_args = [arg[0] for arg in get_func_arguments_and_types(target_func)]
             assert all(arg in target_args for arg in kwargs), \
                 "Failed mapping, arguments missing in target func: %s" % [arg not in target_args for arg in kwargs]
diff --git a/tests/core/test_metric_result_integration.py b/tests/core/test_metric_result_integration.py
index 9d31688d9bcc0..0b797dff0e42f 100644
--- a/tests/core/test_metric_result_integration.py
+++ b/tests/core/test_metric_result_integration.py
@@ -15,10 +15,10 @@
 import torch
 import torch.distributed as dist
 import torch.multiprocessing as mp
+from torchmetrics import Metric
 
 import tests.helpers.utils as tutils
 from pytorch_lightning.core.step_result import Result
-from pytorch_lightning.metrics import Metric
 from tests.helpers.runif import RunIf
 
 
diff --git a/tests/deprecated_api/test_remove_1-5_metrics.py b/tests/deprecated_api/test_remove_1-5_metrics.py
index fcbeaa2e78819..3a526ee7fe470 100644
--- a/tests/deprecated_api/test_remove_1-5_metrics.py
+++ b/tests/deprecated_api/test_remove_1-5_metrics.py
@@ -16,10 +16,9 @@
 import pytest
 import torch
 
+from pytorch_lightning.metrics import Accuracy, MetricCollection
 from pytorch_lightning.metrics.utils import get_num_classes, select_topk, to_categorical, to_onehot
 
-from pytorch_lightning.metrics import MetricCollection, Accuracy
-
 
 def test_v1_5_0_metrics_utils():
     x = torch.tensor([1, 2, 3])
@@ -42,8 +41,8 @@ def test_v1_5_0_metrics_collection():
     target = torch.tensor([0, 2, 0, 2, 0, 1, 0, 2])
     preds = torch.tensor([2, 1, 2, 0, 1, 2, 2, 2])
     with pytest.deprecated_call(
-            match="This `MetricCollection` was deprecated since v1.3.0 in favor of `torchmetrics.MetricCollection`."
-                  " It will be removed in v1.5.0"
+            match="This `MetricCollection` was deprecated since v1.3.0 in favor"
+                  " of `torchmetrics.collections.MetricCollection`. It will be removed in v1.5.0"
     ):
         metrics = MetricCollection([Accuracy()])
     assert metrics(preds, target) == {'Accuracy': torch.Tensor([0.1250])[0]}
diff --git a/tests/metrics/classification/test_precision_recall.py b/tests/metrics/classification/test_precision_recall.py
index f13c1ebe26d3e..c9e5467414832 100644
--- a/tests/metrics/classification/test_precision_recall.py
+++ b/tests/metrics/classification/test_precision_recall.py
@@ -5,9 +5,10 @@
 import pytest
 import torch
 from sklearn.metrics import precision_score, recall_score
+from torchmetrics import Metric
 from torchmetrics.classification.checks import _input_format_classification
 
-from pytorch_lightning.metrics import Metric, Precision, Recall
+from pytorch_lightning.metrics import Precision, Recall
 from pytorch_lightning.metrics.functional import precision, precision_recall, recall
 from tests.metrics.classification.inputs import _input_binary, _input_binary_prob
 from tests.metrics.classification.inputs import _input_multiclass as _input_mcls
diff --git a/tests/metrics/retrieval/test_map.py b/tests/metrics/retrieval/test_map.py
index aa6eeb6424a33..fe43f19b20eb6 100644
--- a/tests/metrics/retrieval/test_map.py
+++ b/tests/metrics/retrieval/test_map.py
@@ -6,9 +6,9 @@
 import pytest
 import torch
 from sklearn.metrics import average_precision_score as sk_average_precision
+from torchmetrics import Metric
 
 from pytorch_lightning import seed_everything
-from pytorch_lightning.metrics.metric import Metric
 from pytorch_lightning.metrics.retrieval.mean_average_precision import RetrievalMAP
 
 
diff --git a/tests/metrics/test_metric_lightning.py b/tests/metrics/test_metric_lightning.py
index 895305fa9da7e..93dd213dd7a89 100644
--- a/tests/metrics/test_metric_lightning.py
+++ b/tests/metrics/test_metric_lightning.py
@@ -1,7 +1,7 @@
 import torch
+from torchmetrics import Metric
 
 from pytorch_lightning import Trainer
-from pytorch_lightning.metrics import Metric, MetricCollection
 from tests.helpers.boring_model import BoringModel
 
 
diff --git a/tests/metrics/utils.py b/tests/metrics/utils.py
index 4bd6608ce3fcf..f1f17d0624936 100644
--- a/tests/metrics/utils.py
+++ b/tests/metrics/utils.py
@@ -8,8 +8,7 @@
 import pytest
 import torch
 from torch.multiprocessing import Pool, set_start_method
-
-from pytorch_lightning.metrics import Metric
+from torchmetrics import Metric
 
 try:
     set_start_method("spawn")
diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index 730838686a060..f20bea32993ff 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -1,13 +1,13 @@
 import pytest
 
-from pytorch_lightning.utilities.deprecation import deprecated_func
+from pytorch_lightning.utilities.deprecation import _deprecated
 
 
 def my_sum(a, b=3):
     return a + b
 
 
-@deprecated_func(target_func=my_sum, ver_deprecate="0.1", ver_remove="0.5")
+@_deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
 def dep_sum(a, b):
     pass
 

From b5c4d21039b1ad300abe24c6cf3c2deeefc5bf0e Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 10:36:21 +0100
Subject: [PATCH 05/11] count

---
 pytorch_lightning/utilities/deprecation.py | 19 +++++++++++--------
 tests/utilities/test_deprecation.py        | 15 +++++++++++++++
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/pytorch_lightning/utilities/deprecation.py b/pytorch_lightning/utilities/deprecation.py
index ba0d0483ee8bb..db4ef039c3580 100644
--- a/pytorch_lightning/utilities/deprecation.py
+++ b/pytorch_lightning/utilities/deprecation.py
@@ -43,15 +43,18 @@ def _deprecated(target: Callable, ver_deprecate: str = "", ver_remove: str = "")
     def inner_function(func):
 
         @wraps(func)
-        def wrapper(*args, **kwargs):
+        def wrapped_fn(*args, **kwargs):
             is_class = inspect.isclass(target)
             target_func = target.__init__ if is_class else target
-            target_str = f'{target.__module__}.{target.__name__}'
-            func_name = func.__qualname__.split('.')[-2] if is_class else func.__name__
-            rank_zero_warn(
-                f"This `{func_name}` was deprecated since v{ver_deprecate} in favor of `{target_str}`."
-                f" It will be removed in v{ver_remove}.", DeprecationWarning
-            )
+            # warn user only once in lifetime
+            if not getattr(inner_function, 'warned', False):
+                target_str = f'{target.__module__}.{target.__name__}'
+                func_name = func.__qualname__.split('.')[-2] if is_class else func.__name__
+                rank_zero_warn(
+                    f"This `{func_name}` was deprecated since v{ver_deprecate} in favor of `{target_str}`."
+                    f" It will be removed in v{ver_remove}.", DeprecationWarning
+                )
+                inner_function.warned = True
 
             if args:  # in case any args passed move them to kwargs
                 # parse only the argument names
@@ -65,6 +68,6 @@ def wrapper(*args, **kwargs):
             # all args were already moved to kwargs
             return target_func(**kwargs)
 
-        return wrapper
+        return wrapped_fn
 
     return inner_function
diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index f20bea32993ff..ee28a90f9e265 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -12,9 +12,24 @@ def dep_sum(a, b):
     pass
 
 
+@_deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
+def dep2_sum(a, b):
+    pass
+
+
 def test_deprecated_func():
     with pytest.deprecated_call(
         match='This `dep_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
         ' It will be removed in v0.5.'
     ):
         assert dep_sum(2, b=5) == 7
+
+    with pytest.warns(None) as record:
+        assert dep_sum(2, b=5) == 7
+    assert len(record) == 0
+
+    with pytest.deprecated_call(
+        match='This `dep2_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
+        ' It will be removed in v0.5.'
+    ):
+        assert dep2_sum(2) == 5

From 8041708094abff60459ea03e60ba91c99ce6ed57 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 10:43:23 +0100
Subject: [PATCH 06/11] flake8

---
 tests/deprecated_api/test_remove_1-5_metrics.py | 4 ++--
 tests/metrics/test_metric_lightning.py          | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/deprecated_api/test_remove_1-5_metrics.py b/tests/deprecated_api/test_remove_1-5_metrics.py
index 3a526ee7fe470..ac91d8acab8a0 100644
--- a/tests/deprecated_api/test_remove_1-5_metrics.py
+++ b/tests/deprecated_api/test_remove_1-5_metrics.py
@@ -41,8 +41,8 @@ def test_v1_5_0_metrics_collection():
     target = torch.tensor([0, 2, 0, 2, 0, 1, 0, 2])
     preds = torch.tensor([2, 1, 2, 0, 1, 2, 2, 2])
     with pytest.deprecated_call(
-            match="This `MetricCollection` was deprecated since v1.3.0 in favor"
-                  " of `torchmetrics.collections.MetricCollection`. It will be removed in v1.5.0"
+        match="This `MetricCollection` was deprecated since v1.3.0 in favor"
+        " of `torchmetrics.collections.MetricCollection`. It will be removed in v1.5.0"
     ):
         metrics = MetricCollection([Accuracy()])
     assert metrics(preds, target) == {'Accuracy': torch.Tensor([0.1250])[0]}
diff --git a/tests/metrics/test_metric_lightning.py b/tests/metrics/test_metric_lightning.py
index 93dd213dd7a89..2e040a881d49f 100644
--- a/tests/metrics/test_metric_lightning.py
+++ b/tests/metrics/test_metric_lightning.py
@@ -1,5 +1,5 @@
 import torch
-from torchmetrics import Metric
+from torchmetrics import Metric, MetricCollection
 
 from pytorch_lightning import Trainer
 from tests.helpers.boring_model import BoringModel

From 866826a665a623841aa81c17fdd8db92537513e9 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <Borda@users.noreply.github.com>
Date: Tue, 16 Mar 2021 12:57:00 +0100
Subject: [PATCH 07/11] Apply suggestions from code review

---
 tests/utilities/test_deprecation.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index ee28a90f9e265..25e481d789194 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -24,10 +24,12 @@ def test_deprecated_func():
     ):
         assert dep_sum(2, b=5) == 7
 
+    # check that the warning is raised only once per function
     with pytest.warns(None) as record:
         assert dep_sum(2, b=5) == 7
     assert len(record) == 0
 
+    # and does not affect other functions
     with pytest.deprecated_call(
         match='This `dep2_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
         ' It will be removed in v0.5.'

From 82f53c4feb41fc1cb7ecfe937eac07abcc15eda4 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 13:02:38 +0100
Subject: [PATCH 08/11] rename

---
 pytorch_lightning/metrics/metric.py           |  4 ++--
 pytorch_lightning/metrics/utils.py            | 20 +++++++++----------
 pytorch_lightning/utilities/deprecation.py    |  4 ++--
 .../deprecated_api/test_remove_1-5_metrics.py |  2 +-
 tests/utilities/test_deprecation.py           |  6 +++---
 5 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/pytorch_lightning/metrics/metric.py b/pytorch_lightning/metrics/metric.py
index d4d621b158303..918c92049846e 100644
--- a/pytorch_lightning/metrics/metric.py
+++ b/pytorch_lightning/metrics/metric.py
@@ -16,7 +16,7 @@
 from torchmetrics import Metric as _Metric
 from torchmetrics.collections import MetricCollection as _MetricCollection
 
-from pytorch_lightning.utilities.deprecation import _deprecated
+from pytorch_lightning.utilities.deprecation import deprecated
 from pytorch_lightning.utilities.distributed import rank_zero_warn
 
 
@@ -51,6 +51,6 @@ class MetricCollection(_MetricCollection):
         Use :class:`torchmetrics.MetricCollection`. Will be removed in v1.5.0.
     """
 
-    @_deprecated(target=_MetricCollection, ver_deprecate="1.3.0", ver_remove="1.5.0")
+    @deprecated(target=_MetricCollection, ver_deprecate="1.3.0", ver_remove="1.5.0")
     def __init__(self, metrics: Union[List[Metric], Tuple[Metric], Dict[str, Metric]]):
         pass
diff --git a/pytorch_lightning/metrics/utils.py b/pytorch_lightning/metrics/utils.py
index 5cbb8a877948a..d0e86d50345e5 100644
--- a/pytorch_lightning/metrics/utils.py
+++ b/pytorch_lightning/metrics/utils.py
@@ -24,20 +24,20 @@
 from torchmetrics.utilities.distributed import class_reduce as __class_reduce
 from torchmetrics.utilities.distributed import reduce as __reduce
 
-from pytorch_lightning.utilities.deprecation import _deprecated
+from pytorch_lightning.utilities.deprecation import deprecated
 
 
-@_deprecated(target=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_cat(x):
     pass
 
 
-@_deprecated(target=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_sum(x):
     pass
 
 
-@_deprecated(target=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_mean(x):
     pass
 
@@ -71,7 +71,7 @@ def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
     return [torch.tensor(x, dtype=torch.int64) for x in indexes.values()]
 
 
-@_deprecated(target=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) -> torch.Tensor:
     """
     .. deprecated::
@@ -79,7 +79,7 @@ def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) ->
     """
 
 
-@_deprecated(target=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -87,7 +87,7 @@ def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch
     """
 
 
-@_deprecated(target=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -95,7 +95,7 @@ def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
 
 
-@_deprecated(target=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optional[int] = None) -> int:
     """
     .. deprecated::
@@ -103,7 +103,7 @@ def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optio
     """
 
 
-@_deprecated(target=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
     .. deprecated::
@@ -111,7 +111,7 @@ def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
 
 
-@_deprecated(target=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def class_reduce(
     num: torch.Tensor, denom: torch.Tensor, weights: torch.Tensor, class_reduction: str = "none"
 ) -> torch.Tensor:
diff --git a/pytorch_lightning/utilities/deprecation.py b/pytorch_lightning/utilities/deprecation.py
index db4ef039c3580..3e2034c6a0453 100644
--- a/pytorch_lightning/utilities/deprecation.py
+++ b/pytorch_lightning/utilities/deprecation.py
@@ -34,7 +34,7 @@ def get_func_arguments_and_types(func: Callable) -> List[Tuple[str, Tuple, Any]]
     return name_type_default
 
 
-def _deprecated(target: Callable, ver_deprecate: str = "", ver_remove: str = "") -> Callable:
+def deprecated(target: Callable, ver_deprecate: str = "", ver_remove: str = "") -> Callable:
     """
     Decorate a function or class ``__init__`` with warning message
      and pass all arguments directly to the target class/method.
@@ -51,7 +51,7 @@ def wrapped_fn(*args, **kwargs):
                 target_str = f'{target.__module__}.{target.__name__}'
                 func_name = func.__qualname__.split('.')[-2] if is_class else func.__name__
                 rank_zero_warn(
-                    f"This `{func_name}` was deprecated since v{ver_deprecate} in favor of `{target_str}`."
+                    f"The `{func_name}` was deprecated since v{ver_deprecate} in favor of `{target_str}`."
                     f" It will be removed in v{ver_remove}.", DeprecationWarning
                 )
                 inner_function.warned = True
diff --git a/tests/deprecated_api/test_remove_1-5_metrics.py b/tests/deprecated_api/test_remove_1-5_metrics.py
index ac91d8acab8a0..7c8c9ad296416 100644
--- a/tests/deprecated_api/test_remove_1-5_metrics.py
+++ b/tests/deprecated_api/test_remove_1-5_metrics.py
@@ -41,7 +41,7 @@ def test_v1_5_0_metrics_collection():
     target = torch.tensor([0, 2, 0, 2, 0, 1, 0, 2])
     preds = torch.tensor([2, 1, 2, 0, 1, 2, 2, 2])
     with pytest.deprecated_call(
-        match="This `MetricCollection` was deprecated since v1.3.0 in favor"
+        match="The `MetricCollection` was deprecated since v1.3.0 in favor"
         " of `torchmetrics.collections.MetricCollection`. It will be removed in v1.5.0"
     ):
         metrics = MetricCollection([Accuracy()])
diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index 25e481d789194..03d07d4147b61 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -1,18 +1,18 @@
 import pytest
 
-from pytorch_lightning.utilities.deprecation import _deprecated
+from pytorch_lightning.utilities.deprecation import deprecated
 
 
 def my_sum(a, b=3):
     return a + b
 
 
-@_deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
+@deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
 def dep_sum(a, b):
     pass
 
 
-@_deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
+@deprecated(target=my_sum, ver_deprecate="0.1", ver_remove="0.5")
 def dep2_sum(a, b):
     pass
 

From 1b2b95c2a005d5e1def665c12da328a076be9588 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 13:04:58 +0100
Subject: [PATCH 09/11] call

---
 tests/utilities/test_deprecation.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index 03d07d4147b61..ef8456491b78b 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -1,6 +1,7 @@
 import pytest
 
 from pytorch_lightning.utilities.deprecation import deprecated
+from tests.helpers.utils import no_warning_call
 
 
 def my_sum(a, b=3):
@@ -25,9 +26,8 @@ def test_deprecated_func():
         assert dep_sum(2, b=5) == 7
 
     # check that the warning is raised only once per function
-    with pytest.warns(None) as record:
+    with no_warning_call(DeprecationWarning):
         assert dep_sum(2, b=5) == 7
-    assert len(record) == 0
 
     # and does not affect other functions
     with pytest.deprecated_call(

From 833aef7b464e2ed44ca11ca7961ba57cd316d435 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 13:21:25 +0100
Subject: [PATCH 10/11] typo

---
 tests/utilities/test_deprecation.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/utilities/test_deprecation.py b/tests/utilities/test_deprecation.py
index ef8456491b78b..7c653c07ad168 100644
--- a/tests/utilities/test_deprecation.py
+++ b/tests/utilities/test_deprecation.py
@@ -20,7 +20,7 @@ def dep2_sum(a, b):
 
 def test_deprecated_func():
     with pytest.deprecated_call(
-        match='This `dep_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
+        match='The `dep_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
         ' It will be removed in v0.5.'
     ):
         assert dep_sum(2, b=5) == 7
@@ -31,7 +31,7 @@ def test_deprecated_func():
 
     # and does not affect other functions
     with pytest.deprecated_call(
-        match='This `dep2_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
+        match='The `dep2_sum` was deprecated since v0.1 in favor of `tests.utilities.test_deprecation.my_sum`.'
         ' It will be removed in v0.5.'
     ):
         assert dep2_sum(2) == 5

From 598a34b348750e7488902f5d0e0b937bb5d7140b Mon Sep 17 00:00:00 2001
From: Jirka Borovec <jirka.borovec@seznam.cz>
Date: Tue, 16 Mar 2021 15:17:39 +0100
Subject: [PATCH 11/11] __

---
 pytorch_lightning/metrics/utils.py | 36 +++++++++++++++---------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/pytorch_lightning/metrics/utils.py b/pytorch_lightning/metrics/utils.py
index d0e86d50345e5..b758e317c6c8d 100644
--- a/pytorch_lightning/metrics/utils.py
+++ b/pytorch_lightning/metrics/utils.py
@@ -14,30 +14,30 @@
 from typing import List, Optional
 
 import torch
-from torchmetrics.utilities.data import dim_zero_cat as __dim_zero_cat
-from torchmetrics.utilities.data import dim_zero_mean as __dim_zero_mean
-from torchmetrics.utilities.data import dim_zero_sum as __dim_zero_sum
-from torchmetrics.utilities.data import get_num_classes as __get_num_classes
-from torchmetrics.utilities.data import select_topk as __select_topk
-from torchmetrics.utilities.data import to_categorical as __to_categorical
-from torchmetrics.utilities.data import to_onehot as __to_onehot
-from torchmetrics.utilities.distributed import class_reduce as __class_reduce
-from torchmetrics.utilities.distributed import reduce as __reduce
+from torchmetrics.utilities.data import dim_zero_cat as _dim_zero_cat
+from torchmetrics.utilities.data import dim_zero_mean as _dim_zero_mean
+from torchmetrics.utilities.data import dim_zero_sum as _dim_zero_sum
+from torchmetrics.utilities.data import get_num_classes as _get_num_classes
+from torchmetrics.utilities.data import select_topk as _select_topk
+from torchmetrics.utilities.data import to_categorical as _to_categorical
+from torchmetrics.utilities.data import to_onehot as _to_onehot
+from torchmetrics.utilities.distributed import class_reduce as _class_reduce
+from torchmetrics.utilities.distributed import reduce as _reduce
 
 from pytorch_lightning.utilities.deprecation import deprecated
 
 
-@deprecated(target=__dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_dim_zero_cat, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_cat(x):
     pass
 
 
-@deprecated(target=__dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_dim_zero_sum, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_sum(x):
     pass
 
 
-@deprecated(target=__dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_dim_zero_mean, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def dim_zero_mean(x):
     pass
 
@@ -71,7 +71,7 @@ def get_group_indexes(idx: torch.Tensor) -> List[torch.Tensor]:
     return [torch.tensor(x, dtype=torch.int64) for x in indexes.values()]
 
 
-@deprecated(target=__to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_to_onehot, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) -> torch.Tensor:
     """
     .. deprecated::
@@ -79,7 +79,7 @@ def to_onehot(label_tensor: torch.Tensor, num_classes: Optional[int] = None) ->
     """
 
 
-@deprecated(target=__select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_select_topk, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -87,7 +87,7 @@ def select_topk(prob_tensor: torch.Tensor, topk: int = 1, dim: int = 1) -> torch
     """
 
 
-@deprecated(target=__to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_to_categorical, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
     .. deprecated::
@@ -95,7 +95,7 @@ def to_categorical(tensor: torch.Tensor, argmax_dim: int = 1) -> torch.Tensor:
     """
 
 
-@deprecated(target=__get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_get_num_classes, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optional[int] = None) -> int:
     """
     .. deprecated::
@@ -103,7 +103,7 @@ def get_num_classes(pred: torch.Tensor, target: torch.Tensor, num_classes: Optio
     """
 
 
-@deprecated(target=__reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
     .. deprecated::
@@ -111,7 +111,7 @@ def reduce(to_reduce: torch.Tensor, reduction: str) -> torch.Tensor:
     """
 
 
-@deprecated(target=__class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
+@deprecated(target=_class_reduce, ver_deprecate="1.3.0", ver_remove="1.5.0")
 def class_reduce(
     num: torch.Tensor, denom: torch.Tensor, weights: torch.Tensor, class_reduction: str = "none"
 ) -> torch.Tensor: