Fix bc break of fp16 (open-mmlab#3822)

* fix bc break of mmdet.core.fp16, refactor import of wrap_fp16_model

* changed warning method

* added docstring for Depr_Fp16OptimizerHook

* docformatter

* fix docstring

* changed names from depr to deprecated

Author: RyanXLi

.dev_scripts/batch_test.py

@@ -18,10 +18,10 @@
 import torch
 from mmcv import Config, get_logger
 from mmcv.parallel import MMDataParallel, MMDistributedDataParallel
-from mmcv.runner import get_dist_info, init_dist, load_checkpoint
+from mmcv.runner import (get_dist_info, init_dist, load_checkpoint,
+                         wrap_fp16_model)
 
 from mmdet.apis import multi_gpu_test, single_gpu_test
-from mmdet.core import wrap_fp16_model
 from mmdet.datasets import (build_dataloader, build_dataset,
                             replace_ImageToTensor)
 from mmdet.models import build_detector

mmdet/core/__init__.py

@@ -1,6 +1,7 @@
 from .anchor import *  # noqa: F401, F403
 from .bbox import *  # noqa: F401, F403
 from .evaluation import *  # noqa: F401, F403
+from .fp16 import *  # noqa: F401, F403
 from .mask import *  # noqa: F401, F403
 from .post_processing import *  # noqa: F401, F403
 from .utils import *  # noqa: F401, F403

mmdet/core/fp16/__init__.py

@@ -0,0 +1,8 @@
+from .deprecated_fp16_utils import \
+    DeprecatedFp16OptimizerHook as Fp16OptimizerHook
+from .deprecated_fp16_utils import deprecated_auto_fp16 as auto_fp16
+from .deprecated_fp16_utils import deprecated_force_fp32 as force_fp32
+from .deprecated_fp16_utils import \
+    deprecated_wrap_fp16_model as wrap_fp16_model
+
+__all__ = ['auto_fp16', 'force_fp32', 'Fp16OptimizerHook', 'wrap_fp16_model']

mmdet/core/fp16/deprecated_fp16_utils.py

@@ -0,0 +1,47 @@
+import warnings
+
+from mmcv.runner import (Fp16OptimizerHook, auto_fp16, force_fp32,
+                         wrap_fp16_model)
+
+
+class DeprecatedFp16OptimizerHook(Fp16OptimizerHook):
+    """A wrapper class for the FP16 optimizer hook. This class wraps
+    :class:`Fp16OptimizerHook` in `mmcv.runner` and shows a warning that the
+    :class:`Fp16OptimizerHook` from `mmdet.core` will be deprecated.
+
+    Refer to :class:`Fp16OptimizerHook` in `mmcv.runner` for more details.
+
+    Args:
+        loss_scale (float): Scale factor multiplied with loss.
+    """
+
+    def __init__(*args, **kwargs):
+        super().__init__(*args, **kwargs)
+        warnings.warn(
+            'Importing Fp16OptimizerHook from "mmdet.core" will be '
+            'deprecated in the future. Please import them from "mmcv.runner" '
+            'instead')
+
+
+def deprecated_auto_fp16(*args, **kwargs):
+    warnings.warn(
+        'Importing auto_fp16 from "mmdet.core" will be '
+        'deprecated in the future. Please import them from "mmcv.runner" '
+        'instead')
+    return auto_fp16(*args, **kwargs)
+
+
+def deprecated_force_fp32(*args, **kwargs):
+    warnings.warn(
+        'Importing force_fp32 from "mmdet.core" will be '
+        'deprecated in the future. Please import them from "mmcv.runner" '
+        'instead')
+    return force_fp32(*args, **kwargs)
+
+
+def deprecated_wrap_fp16_model(*args, **kwargs):
+    warnings.warn(
+        'Importing wrap_fp16_model from "mmdet.core" will be '
+        'deprecated in the future. Please import them from "mmcv.runner" '
+        'instead')
+    wrap_fp16_model(*args, **kwargs)

tools/benchmark.py

@@ -5,8 +5,7 @@
 from mmcv import Config
 from mmcv.cnn import fuse_conv_bn
 from mmcv.parallel import MMDataParallel
-from mmcv.runner import load_checkpoint
-from mmcv.runner.fp16_utils import wrap_fp16_model
+from mmcv.runner import load_checkpoint, wrap_fp16_model
 
 from mmdet.datasets import (build_dataloader, build_dataset,
                             replace_ImageToTensor)

tools/test.py

@@ -7,18 +7,14 @@
 from mmcv import Config, DictAction
 from mmcv.cnn import fuse_conv_bn
 from mmcv.parallel import MMDataParallel, MMDistributedDataParallel
-from mmcv.runner import get_dist_info, init_dist, load_checkpoint
+from mmcv.runner import (get_dist_info, init_dist, load_checkpoint,
+                         wrap_fp16_model)
 
 from mmdet.apis import multi_gpu_test, single_gpu_test
 from mmdet.datasets import (build_dataloader, build_dataset,
                             replace_ImageToTensor)
 from mmdet.models import build_detector
 
-try:
-    from mmcv.runner import wrap_fp16_model
-except ImportError:
-    from mmcv.runner.fp16_utils import wrap_fp16_model
-
 
 def parse_args():
     parser = argparse.ArgumentParser(

tools/test_robustness.py

@@ -9,7 +9,8 @@
 import torch
 import torch.distributed as dist
 from mmcv.parallel import MMDataParallel, MMDistributedDataParallel
-from mmcv.runner import get_dist_info, init_dist, load_checkpoint
+from mmcv.runner import (get_dist_info, init_dist, load_checkpoint,
+                         wrap_fp16_model)
 from pycocotools.coco import COCO
 from pycocotools.cocoeval import COCOeval
 from robustness_eval import get_results
@@ -20,11 +21,6 @@
 from mmdet.datasets import build_dataloader, build_dataset
 from mmdet.models import build_detector
 
-try:
-    from mmcv.runner import wrap_fp16_model
-except ImportError:
-    from mmcv.runner.fp16_utils import wrap_fp16_model
-
 
 def coco_eval_with_return(result_files,
                           result_types,