add check for distributed optimizer which is unsupported for PEFT (NV…

…IDIA#8323)

Signed-off-by: Chen Cui <chcui@nvidia.com>

nemo/collections/nlp/parts/mixins/nlp_adapter_mixins.py

@@ -175,6 +175,8 @@ def add_adapter(self, peft_cfgs: Union[PEFTConfig, List[PEFTConfig]]):
 
         if self.cfg.get('virtual_pipeline_model_parallel_size', None):
             raise ValueError('Virtual pipeline model parallel is not supported when using PEFT')
+        if self.cfg.optim.name == "distributed_fused_adam":
+            raise ValueError('distributed_fused_adam is not supported for PEFT. Please use fused_adam')
 
         if not isinstance(peft_cfgs, List):
             peft_cfgs = [peft_cfgs]