fix

src/lerobot/scripts/train.py

@@ -165,7 +165,15 @@ def train(cfg: TrainPipelineConfig):
 
     # Initialize Accelerate if enabled
     accelerator = None
-    if cfg.use_accelerate:
+    logging.info(f"DEBUG: cfg.use_accelerate = {cfg.use_accelerate}")
+
+    # Auto-detect if we're using accelerate launch (fallback)
+    import os
+
+    using_accelerate_launch = "ACCELERATE_LAUNCH" in os.environ or "WORLD_SIZE" in os.environ
+    logging.info(f"DEBUG: Auto-detected accelerate launch = {using_accelerate_launch}")
+
+    if cfg.use_accelerate or using_accelerate_launch:
         ddp_kwargs = DistributedDataParallelKwargs(find_unused_parameters=True)
         accelerator = Accelerator(
             gradient_accumulation_steps=cfg.gradient_accumulation_steps,
@@ -174,8 +182,9 @@ def train(cfg: TrainPipelineConfig):
         )
         device = accelerator.device
         if accelerator.is_main_process:
+            accelerate_source = "config" if cfg.use_accelerate else "auto-detected from accelerate launch"
             logging.info(
-                f"Accelerate initialized with device: {device}, mixed_precision: {cfg.mixed_precision}"
+                f"Accelerate initialized with device: {device}, mixed_precision: {cfg.mixed_precision} (source: {accelerate_source})"
             )
             logging.info(f"Training on {accelerator.num_processes} processes")
     else: