debug tpu

Author: four4fish

pytorch_lightning/trainer/connectors/accelerator_connector.py

@@ -485,16 +485,15 @@ def _is_slurm_managing_tasks(self):
         return num_slurm_tasks == total_requested_devices
 
     def _choose_strategy(self):
-        if _HOROVOD_AVAILABLE and ("OMPI_COMM_WORLD_RANK" in os.environ or "HOROVOD_RANK" in os.environ):
-            self._strategy_flag = HorovodStrategy()
-
         if self._accelerator_flag == "ipu":
             self._strategy_flag = "ipu"
         elif self._accelerator_flag == "tpu":
             if self._parallel_devices and len(self._parallel_devices) > 1:
                 self._strategy_flag = "tpu_spawn"
             else:
                 self._srategy_flag = SingleTPUStrategy(device=self._parallel_devices[0])
+        elif _HOROVOD_AVAILABLE and ("OMPI_COMM_WORLD_RANK" in os.environ or "HOROVOD_RANK" in os.environ):
+            self._strategy_flag = HorovodStrategy()
         else:
             if self._num_nodes_flag > 1:
                 self._strategy_flag = "ddp"
@@ -549,8 +548,10 @@ def _strategy_check_and_fallbacks(self):
     def _init_strategy(self):
         if isinstance(self._strategy_flag, str):
             self.strategy = StrategyRegistry.get(self._strategy_flag)
-        else:
+        elif isinstance(self._strategy_flag, Strategy):
             self.strategy = self._strategy_flag
+        else:
+            raise RuntimeError(f"{self.strategy} is not valid type: {self.strategy}")
 
     def handle_horovod(self):
         if self._num_nodes_flag > 1: