[v2.0] Refactor code hierarchy (part 2) (#2987)

nni/nas/pytorch/cdarts/trainer.py → nni/algorithms/nas/pytorch/cdarts/trainer.py

@@ -10,7 +10,7 @@ import torch.nn as nn
 import torch.nn.functional as F
 import apex  # pylint: disable=import-error
 from apex.parallel import DistributedDataParallel  # pylint: disable=import-error
-from nni.nas.pytorch.cdarts import RegularizedDartsMutator, RegularizedMutatorParallel, DartsDiscreteMutator  # pylint: disable=wrong-import-order
+from .mutator import RegularizedDartsMutator, RegularizedMutatorParallel, DartsDiscreteMutator  # pylint: disable=wrong-import-order
 from nni.nas.pytorch.utils import AverageMeterGroup  # pylint: disable=wrong-import-order
 
 from .utils import CyclicIterator, TorchTensorEncoder, accuracy, reduce_metrics

nni/nas/pytorch/classic_nas/mutator.py → nni/algorithms/nas/pytorch/classic_nas/mutator.py

@@ -9,7 +9,7 @@ import sys
 import torch
 
 import nni
-from nni.env_vars import trial_env_vars
+from nni.runtime.env_vars import trial_env_vars
 from nni.nas.pytorch.mutables import LayerChoice, InputChoice, MutableScope
 from nni.nas.pytorch.mutator import Mutator