Add 'wrap_fp16_model' to __init__.py (#555)

* add 'wrap_fp16_model' to __inti__.py

* add 'wrap_fp16_model' to __init__.py

mmcv/runner/__init__.py

@@ -4,7 +4,7 @@ from .checkpoint import (_load_checkpoint, load_checkpoint, load_state_dict,
                          save_checkpoint, weights_to_cpu)
 from .dist_utils import get_dist_info, init_dist, master_only
 from .epoch_based_runner import EpochBasedRunner, Runner
-from .fp16_utils import auto_fp16, force_fp32
+from .fp16_utils import auto_fp16, force_fp32, wrap_fp16_model
 from .hooks import (HOOKS, CheckpointHook, ClosureHook, DistSamplerSeedHook,
                     EMAHook, Fp16OptimizerHook, Hook, IterTimerHook,
                     LoggerHook, LrUpdaterHook, MlflowLoggerHook, OptimizerHook,
@@ -29,6 +29,6 @@ __all__ = [
     'obj_from_dict', 'init_dist', 'get_dist_info', 'master_only',
     'OPTIMIZER_BUILDERS', 'OPTIMIZERS', 'DefaultOptimizerConstructor',
     'build_optimizer', 'build_optimizer_constructor', 'IterLoader',
-    'set_random_seed', 'auto_fp16', 'force_fp32', 'Fp16OptimizerHook',
-    'SyncBuffersHook', 'EMAHook'
+    'set_random_seed', 'auto_fp16', 'force_fp32', 'wrap_fp16_model',
+    'Fp16OptimizerHook', 'SyncBuffersHook', 'EMAHook'
 ]