Fix DistribType for ddp_cpu (spawn) (#7492)

Author: alanhdu

CHANGELOG.md

@@ -42,6 +42,33 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Removed
 
+- Prune deprecated classif. metrics from `pytorch_lightning.metrics.functional.classification` ([7499](https://github.com/PyTorchLightning/pytorch-lightning/pull/7499))
+
+
+- Removed deprecated data parallel classes `LightningDataParallel` and `LightningDistributedDataParallel` from `pytorch_lightning.overrides.data_parallel` ([7510](https://github.com/PyTorchLightning/pytorch-lightning/pull/7510))
+
+
+- Removed deprecated trainer attributes - `get_model` and `accelerator_backend` ([7502](https://github.com/PyTorchLightning/pytorch-lightning/pull/7502))
+
+
+- Removed deprecated utils modules `model_utils`, `warning_utils`, `xla_device_utils` and partially `argparse_utils` ([7503](https://github.com/PyTorchLightning/pytorch-lightning/pull/7503))
+
+
+- Removed deprecated trainer attributes - `on_cpu`, `on_tpu`, `use_tpu`, `on_gpu`, `use_dp`, `use_ddp`, `use_ddp2`, `use_horovod`, `use_single_gpu` ([#7501](https://github.com/PyTorchLightning/pytorch-lightning/pull/7501))
+
+
+### Fixed
+
+
+- Fixed parsing of multiple training dataloaders ([#7433](https://github.com/PyTorchLightning/pytorch-lightning/pull/7433))
+
+
+- Fixed recursive passing of `wrong_type` keyword argument in `pytorch_lightning.utilities.apply_to_collection` ([#7433](https://github.com/PyTorchLightning/pytorch-lightning/pull/7433))
+
+
+- Fixed setting correct `DistribType` for `ddp_cpu` (spawn) backend ([#7492](https://github.com/PyTorchLightning/pytorch-lightning/pull/7492))
+
+
 ## [1.3.1] - 2021-05-11
 
 ### Fixed

pytorch_lightning/trainer/connectors/accelerator_connector.py

@@ -522,7 +522,7 @@ def set_distributed_mode(self, distributed_backend: Optional[str] = None):
 
         # special case with DDP on CPUs
         if self.distributed_backend == "ddp_cpu":
-            self._distrib_type = DistributedType.DDP
+            self._distrib_type = DistributedType.DDP_SPAWN
             if self.num_gpus > 0:
                 rank_zero_warn(
                     'You requested one or more GPUs, but set the backend to `ddp_cpu`. Training will not use GPUs.'

tests/accelerators/test_accelerator_connector.py

@@ -437,13 +437,15 @@ def test_ipython_incompatible_backend_error(*_):
     with pytest.raises(MisconfigurationException, match="backend ddp is not compatible"):
         Trainer(accelerator="ddp", gpus=2)
 
-    with pytest.raises(MisconfigurationException, match="backend ddp is not compatible"):
-        Trainer(accelerator="ddp_cpu", num_processes=2)
-
     with pytest.raises(MisconfigurationException, match="backend ddp2 is not compatible"):
         Trainer(accelerator="ddp2", gpus=2)
 
 
+@mock.patch("pytorch_lightning.utilities._IS_INTERACTIVE", return_value=True)
+def test_ipython_compatible_backend(*_):
+    Trainer(accelerator="ddp_cpu", num_processes=2)
+
+
 @pytest.mark.parametrize(
     ["accelerator", "plugin"],
     [('ddp_spawn', 'ddp_sharded'), (None, 'ddp_sharded')],

tests/trainer/test_trainer.py

@@ -1140,18 +1140,6 @@ def test_num_sanity_val_steps_neg_one(tmpdir, limit_val_batches):
                 num_processes=1,
             ),
         ),
-        (
-            dict(accelerator="dp", gpus=None),
-            dict(
-                use_dp=False,
-                use_ddp=False,
-                use_ddp2=False,
-                num_gpus=0,
-                on_gpu=False,
-                use_single_gpu=False,
-                num_processes=1,
-            ),
-        ),
         (
             dict(accelerator="ddp", gpus=None),
             dict(