Extend Trainer to enable Ascend NPU to use the fused Adamw optimizer when training (#26194)

src/transformers/trainer.py

@@ -1068,6 +1068,14 @@ class Trainer:
                 optimizer_kwargs.update(adam_kwargs)
             except ImportError:
                 raise ValueError("Trainer failed to import syncfree AdamW from torch_xla.")
+        elif args.optim == OptimizerNames.ADAMW_TORCH_NPU_FUSED:
+            try:
+                from torch_npu.optim import NpuFusedAdamW
+
+                optimizer_cls = NpuFusedAdamW
+                optimizer_kwargs.update(adam_kwargs)
+            except ImportError:
+                raise ValueError("Trainer failed to import FusedAdamW from torch_npu.")
         elif args.optim == OptimizerNames.ADAMW_APEX_FUSED:
             try:
                 from apex.optimizers import FusedAdam

src/transformers/training_args.py

@@ -140,6 +140,7 @@ class OptimizerNames(ExplicitEnum):
     ADAMW_TORCH = "adamw_torch"
     ADAMW_TORCH_FUSED = "adamw_torch_fused"
     ADAMW_TORCH_XLA = "adamw_torch_xla"
+    ADAMW_TORCH_NPU_FUSED = "adamw_torch_npu_fused"
     ADAMW_APEX_FUSED = "adamw_apex_fused"
     ADAFACTOR = "adafactor"
     ADAMW_ANYPRECISION = "adamw_anyprecision"