Dropout and Max Norm Regularization for LoRA training (#545)

* Instantiate max_norm

* minor

* Move to end of step

* argparse

* metadata

* phrasing

* Sqrt ratio and logging

* fix logging

* Dropout test

* Dropout Args

* Dropout changed to affect LoRA only

---------

Co-authored-by: Kohya S <52813779+kohya-ss@users.noreply.github.com>

library/custom_train_functions.py

@@ -434,3 +434,36 @@ def perlin_noise(noise, device, octaves):
     noise += noise_perlin # broadcast for each batch
     return noise / noise.std()  # Scaled back to roughly unit variance
 """
+
+def max_norm(state_dict, max_norm_value):
+  downkeys = []
+  upkeys = []
+  norms = []
+  keys_scaled = 0
+
+  for key in state_dict.keys():
+    if "lora_down" in key and "weight" in key:
+      downkeys.append(key)
+      upkeys.append(key.replace("lora_down","lora_up"))
+  for i in range(len(downkeys)):
+    down = state_dict[downkeys[i]].cuda()
+    up = state_dict[upkeys[i]].cuda()
+    if up.shape[2:] == (1, 1) and down.shape[2:] == (1, 1):
+        updown = (up.squeeze(2).squeeze(2) @ down.squeeze(2).squeeze(2)).unsqueeze(2).unsqueeze(3)
+    elif up.shape[2:] == (3, 3) or down.shape[2:] == (3, 3):
+        updown = torch.nn.functional.conv2d(down.permute(1, 0, 2, 3), up).permute(1, 0, 2, 3)
+    else:
+        updown = up @ down
+    norm = updown.norm().clamp(min=max_norm_value/2)
+    desired = torch.clamp(norm, max=max_norm_value)
+    ratio = desired.cpu() / norm.cpu()
+    sqrt_ratio = ratio **0.5
+    if ratio != 1:
+      keys_scaled +=1
+      state_dict[upkeys[i]] *= sqrt_ratio
+      state_dict[downkeys[i]] *= sqrt_ratio
+    scalednorm = updown.norm()*ratio
+    norms.append(scalednorm.item())
+  
+  return keys_scaled, sum(norms)/len(norms), max(norms)
+

networks/lora.py

@@ -19,7 +19,7 @@ class LoRAModule(torch.nn.Module):
     replaces forward method of the original Linear, instead of replacing the original Linear module.
     """
 
-    def __init__(self, lora_name, org_module: torch.nn.Module, multiplier=1.0, lora_dim=4, alpha=1):
+    def __init__(self, lora_name, org_module: torch.nn.Module, multiplier=1.0, lora_dim=4, alpha=1, dropout=None):
         """if alpha == 0 or None, alpha is rank (no scaling)."""
         super().__init__()
         self.lora_name = lora_name
@@ -60,6 +60,7 @@ class LoRAModule(torch.nn.Module):
 
         self.multiplier = multiplier
         self.org_module = org_module  # remove in applying
+        self.dropout = dropout
 
     def apply_to(self):
         self.org_forward = self.org_module.forward
@@ -67,6 +68,9 @@ class LoRAModule(torch.nn.Module):
         del self.org_module
 
     def forward(self, x):
+        if self.dropout:
+          return self.org_forward(x) + self.lora_up(torch.nn.functional.dropout(self.lora_down(x),p=self.dropout)) * self.multiplier * self.scale
+        else:
           return self.org_forward(x) + self.lora_up(self.lora_down(x)) * self.multiplier * self.scale
 
 
@@ -348,7 +352,7 @@ def parse_block_lr_kwargs(nw_kwargs):
     return down_lr_weight, mid_lr_weight, up_lr_weight
 
 
-def create_network(multiplier, network_dim, network_alpha, vae, text_encoder, unet, **kwargs):
+def create_network(multiplier, network_dim, network_alpha, vae, text_encoder, unet, dropout=None, **kwargs):
     if network_dim is None:
         network_dim = 4  # default
     if network_alpha is None:
@@ -403,6 +407,7 @@ def create_network(multiplier, network_dim, network_alpha, vae, text_encoder, un
         conv_block_dims=conv_block_dims,
         conv_block_alphas=conv_block_alphas,
         varbose=True,
+        dropout=dropout,
     )
 
     if up_lr_weight is not None or mid_lr_weight is not None or down_lr_weight is not None:
@@ -681,6 +686,7 @@ class LoRANetwork(torch.nn.Module):
         modules_alpha=None,
         module_class=LoRAModule,
         varbose=False,
+        dropout=None
     ) -> None:
         """
         LoRA network: すごく引数が多いが、パターンは以下の通り
@@ -697,6 +703,8 @@ class LoRANetwork(torch.nn.Module):
         self.alpha = alpha
         self.conv_lora_dim = conv_lora_dim
         self.conv_alpha = conv_alpha
+        self.dropout = dropout
+        print(f"Neuron dropout: p={self.dropout}")
 
         if modules_dim is not None:
             print(f"create LoRA network from weights")
@@ -755,7 +763,7 @@ class LoRANetwork(torch.nn.Module):
                                     skipped.append(lora_name)
                                 continue
 
-                            lora = module_class(lora_name, child_module, self.multiplier, dim, alpha)
+                            lora = module_class(lora_name, child_module, self.multiplier, dim, alpha, dropout)
                             loras.append(lora)
             return loras, skipped
 

train_network.py

@@ -25,12 +25,16 @@ from library.config_util import (
 )
 import library.huggingface_util as huggingface_util
 import library.custom_train_functions as custom_train_functions
-from library.custom_train_functions import apply_snr_weight, get_weighted_text_embeddings, pyramid_noise_like, apply_noise_offset
+from library.custom_train_functions import apply_snr_weight, get_weighted_text_embeddings, pyramid_noise_like, apply_noise_offset, max_norm
 
 
 # TODO 他のスクリプトと共通化する
-def generate_step_logs(args: argparse.Namespace, current_loss, avr_loss, lr_scheduler):
+def generate_step_logs(args: argparse.Namespace, current_loss, avr_loss, lr_scheduler, keys_scaled=None, mean_norm=None, maximum_norm=None):
     logs = {"loss/current": current_loss, "loss/average": avr_loss}
+    if args.scale_weight_norms:
+      logs["keys_scaled"] = keys_scaled
+      logs["average_key_norm"] = mean_norm
+      logs["max_key_norm"] = maximum_norm
 
     lrs = lr_scheduler.get_last_lr()
 
@@ -196,13 +200,14 @@ def train(args):
     if args.dim_from_weights:
         network, _ = network_module.create_network_from_weights(1, args.network_weights, vae, text_encoder, unet, **net_kwargs)
     else:
-        network = network_module.create_network(1.0, args.network_dim, args.network_alpha, vae, text_encoder, unet, **net_kwargs)
+        network = network_module.create_network(1.0, args.network_dim, args.network_alpha, vae, text_encoder, unet, args.dropout, **net_kwargs)
     if network is None:
         return
 
     if hasattr(network, "prepare_network"):
         network.prepare_network(args)
 
+
     train_unet = not args.network_train_text_encoder_only
     train_text_encoder = not args.network_train_unet_only
     network.apply_to(text_encoder, unet, train_text_encoder, train_unet)
@@ -375,6 +380,8 @@ def train(args):
         "ss_face_crop_aug_range": args.face_crop_aug_range,
         "ss_prior_loss_weight": args.prior_loss_weight,
         "ss_min_snr_gamma": args.min_snr_gamma,
+        "ss_scale_weight_norms": args.scale_weight_norms,
+        "ss_dropout": args.dropout,
     }
 
     if use_user_config:
@@ -580,6 +587,7 @@ def train(args):
         network.on_epoch_start(text_encoder, unet)
 
         for step, batch in enumerate(train_dataloader):
+
             current_step.value = global_step
             with accelerator.accumulate(network):
                 on_step_start(text_encoder, unet)
@@ -652,6 +660,10 @@ def train(args):
                 lr_scheduler.step()
                 optimizer.zero_grad(set_to_none=True)
             
+            if args.scale_weight_norms:
+              keys_scaled, mean_norm, maximum_norm = max_norm(network.state_dict(), args.scale_weight_norms)
+              max_mean_logs = {"Keys Scaled": keys_scaled, "Average key norm": mean_norm}  
+
             # Checks if the accelerator has performed an optimization step behind the scenes
             if accelerator.sync_gradients:
                 progress_bar.update(1)
@@ -686,9 +698,12 @@ def train(args):
             avr_loss = loss_total / len(loss_list)
             logs = {"loss": avr_loss}  # , "lr": lr_scheduler.get_last_lr()[0]}
             progress_bar.set_postfix(**logs)
+            if args.scale_weight_norms:
+              progress_bar.set_postfix(**max_mean_logs)
+
 
             if args.logging_dir is not None:
-                logs = generate_step_logs(args, current_loss, avr_loss, lr_scheduler)
+                logs = generate_step_logs(args, current_loss, avr_loss, lr_scheduler, keys_scaled, mean_norm, maximum_norm)
                 accelerator.log(logs, step=global_step)
 
             if global_step >= args.max_train_steps:
@@ -787,6 +802,18 @@ def setup_parser() -> argparse.ArgumentParser:
         action="store_true",
         help="automatically determine dim (rank) from network_weights / dim (rank)をnetwork_weightsで指定した重みから自動で決定する",
     )
+    parser.add_argument(
+        "--scale_weight_norms",
+        type=float,
+        default=None,
+        help="Scale the weight of each key pair to help prevent overtraing via exploding gradients. (1 is a good starting point)",
+    )
+    parser.add_argument(
+        "--dropout",
+        type=float,
+        default=None,
+        help="Drops neurons out of training every step (0 is default behavior, 1 would drop all neurons)",
+    )
     parser.add_argument(
         "--base_weights",
         type=str,