fix for multi gpu training

library/train_util.py

@@ -2294,6 +2294,8 @@ def sample_images(accelerator, args: argparse.Namespace, epoch, steps, device, v
   with torch.no_grad():
     with accelerator.autocast():
       for i, prompt in enumerate(prompts):
+        if not accelerator.is_main_process:
+          continue
         prompt = prompt.strip()
         if len(prompt) == 0 or prompt[0] == '#':
           continue
@@ -2351,6 +2353,12 @@ def sample_images(accelerator, args: argparse.Namespace, epoch, steps, device, v
           if negative_prompt is not None:
             negative_prompt = negative_prompt.replace(prompt_replacement[0], prompt_replacement[1])
 
+        print(f"prompt: {prompt}")
+        print(f"negative_prompt: {negative_prompt}")
+        print(f"height: {height}")
+        print(f"width: {width}")
+        print(f"sample_steps: {sample_steps}")
+        print(f"scale: {scale}")
         image = pipeline(prompt, height, width, sample_steps, scale, negative_prompt).images[0]
 
         ts_str = time.strftime('%Y%m%d%H%M%S', time.localtime())

train_network.py

@@ -106,6 +106,7 @@ def train(args):
   # acceleratorを準備する
   print("prepare accelerator")
   accelerator, unwrap_model = train_util.prepare_accelerator(args)
+  is_main_process = accelerator.is_main_process
 
   # mixed precisionに対応した型を用意しておき適宜castする
   weight_dtype, save_dtype = train_util.prepare_dtype(args)
@@ -175,12 +176,13 @@ def train(args):
 
   # 学習ステップ数を計算する
   if args.max_train_epochs is not None:
-    args.max_train_steps = args.max_train_epochs * len(train_dataloader)
+    args.max_train_steps = args.max_train_epochs * math.ceil(len(train_dataloader) / accelerator.num_processes)
+    if is_main_process:
       print(f"override steps. steps for {args.max_train_epochs} epochs is / 指定エポックまでのステップ数: {args.max_train_steps}")
 
   # lr schedulerを用意する
   lr_scheduler = train_util.get_scheduler_fix(args.lr_scheduler, optimizer, num_warmup_steps=args.lr_warmup_steps,
-                                              num_training_steps=args.max_train_steps * args.gradient_accumulation_steps,
+                                              num_training_steps=args.max_train_steps * accelerator.num_processes * args.gradient_accumulation_steps,
                                               num_cycles=args.lr_scheduler_num_cycles, power=args.lr_scheduler_power)
 
   # 実験的機能：勾配も含めたfp16学習を行う　モデル全体をfp16にする
@@ -251,6 +253,8 @@ def train(args):
   # 学習する
   # TODO: find a way to handle total batch size when there are multiple datasets
   total_batch_size = args.train_batch_size * accelerator.num_processes * args.gradient_accumulation_steps
+  
+  if is_main_process:
     print("running training / 学習開始")
     print(f"  num train images * repeats / 学習画像の数×繰り返し回数: {train_dataset_group.num_train_images}")
     print(f"  num reg images / 正則化画像の数: {train_dataset_group.num_reg_images}")
@@ -461,6 +465,7 @@ def train(args):
   loss_list = []
   loss_total = 0.0
   for epoch in range(num_train_epochs):
+    if is_main_process:
       print(f"epoch {epoch+1}/{num_train_epochs}")
     train_dataset_group.set_current_epoch(epoch + 1)
 
@@ -573,6 +578,7 @@ def train(args):
           print(f"removing old checkpoint: {old_ckpt_file}")
           os.remove(old_ckpt_file)
 
+      if is_main_process:
         saving = train_util.save_on_epoch_end(args, save_func, remove_old_func, epoch + 1, num_train_epochs)
         if saving and args.save_state:
           train_util.save_state_on_epoch_end(args, accelerator, model_name, epoch + 1)
@@ -584,7 +590,6 @@ def train(args):
   metadata["ss_epoch"] = str(num_train_epochs)
   metadata["ss_training_finished_at"] = str(time.time())
 
-  is_main_process = accelerator.is_main_process
   if is_main_process:
     network = unwrap_model(network)