194 lines
6.9 KiB
Python
194 lines
6.9 KiB
Python
# LoRA network module
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# reference:
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# https://github.com/microsoft/LoRA/blob/main/loralib/layers.py
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# https://github.com/cloneofsimo/lora/blob/master/lora_diffusion/lora.py
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import math
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import os
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import torch
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class LoRAModule(torch.nn.Module):
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"""
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replaces forward method of the original Linear, instead of replacing the original Linear module.
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"""
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def __init__(self, lora_name, org_module: torch.nn.Module, multiplier=1.0, lora_dim=4):
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super().__init__()
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self.lora_name = lora_name
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if org_module.__class__.__name__ == 'Conv2d':
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in_dim = org_module.in_channels
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out_dim = org_module.out_channels
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self.lora_down = torch.nn.Conv2d(in_dim, lora_dim, (1, 1), bias=False)
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self.lora_up = torch.nn.Conv2d(lora_dim, out_dim, (1, 1), bias=False)
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else:
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in_dim = org_module.in_features
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out_dim = org_module.out_features
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self.lora_down = torch.nn.Linear(in_dim, lora_dim, bias=False)
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self.lora_up = torch.nn.Linear(lora_dim, out_dim, bias=False)
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# same as microsoft's
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torch.nn.init.kaiming_uniform_(self.lora_down.weight, a=math.sqrt(5))
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torch.nn.init.zeros_(self.lora_up.weight)
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self.multiplier = multiplier
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self.org_module = org_module # remove in applying
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def apply_to(self):
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self.org_forward = self.org_module.forward
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self.org_module.forward = self.forward
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del self.org_module
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def forward(self, x):
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return self.org_forward(x) + self.lora_up(self.lora_down(x)) * self.multiplier
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def create_network(multiplier, network_dim, vae, text_encoder, unet, **kwargs):
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if network_dim is None:
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network_dim = 4 # default
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network = LoRANetwork(text_encoder, unet, multiplier=multiplier, lora_dim=network_dim)
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return network
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class LoRANetwork(torch.nn.Module):
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UNET_TARGET_REPLACE_MODULE = ["Transformer2DModel", "Attention"]
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TEXT_ENCODER_TARGET_REPLACE_MODULE = ["CLIPAttention", "CLIPMLP"]
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LORA_PREFIX_UNET = 'lora_unet'
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LORA_PREFIX_TEXT_ENCODER = 'lora_te'
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def __init__(self, text_encoder, unet, multiplier=1.0, lora_dim=4) -> None:
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super().__init__()
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self.multiplier = multiplier
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self.lora_dim = lora_dim
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# create module instances
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def create_modules(prefix, root_module: torch.nn.Module, target_replace_modules) -> list[LoRAModule]:
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loras = []
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for name, module in root_module.named_modules():
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if module.__class__.__name__ in target_replace_modules:
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for child_name, child_module in module.named_modules():
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if child_module.__class__.__name__ == "Linear" or (child_module.__class__.__name__ == "Conv2d" and child_module.kernel_size == (1, 1)):
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lora_name = prefix + '.' + name + '.' + child_name
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lora_name = lora_name.replace('.', '_')
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lora = LoRAModule(lora_name, child_module, self.multiplier, self.lora_dim)
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loras.append(lora)
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return loras
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self.text_encoder_loras = create_modules(LoRANetwork.LORA_PREFIX_TEXT_ENCODER,
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text_encoder, LoRANetwork.TEXT_ENCODER_TARGET_REPLACE_MODULE)
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print(f"create LoRA for Text Encoder: {len(self.text_encoder_loras)} modules.")
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self.unet_loras = create_modules(LoRANetwork.LORA_PREFIX_UNET, unet, LoRANetwork.UNET_TARGET_REPLACE_MODULE)
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print(f"create LoRA for U-Net: {len(self.unet_loras)} modules.")
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self.weights_sd = None
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# assertion
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names = set()
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for lora in self.text_encoder_loras + self.unet_loras:
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assert lora.lora_name not in names, f"duplicated lora name: {lora.lora_name}"
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names.add(lora.lora_name)
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def load_weights(self, file):
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if os.path.splitext(file)[1] == '.safetensors':
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from safetensors.torch import load_file, safe_open
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self.weights_sd = load_file(file)
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else:
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self.weights_sd = torch.load(file, map_location='cpu')
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def apply_to(self, text_encoder, unet, apply_text_encoder=None, apply_unet=None):
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if self.weights_sd:
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weights_has_text_encoder = weights_has_unet = False
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for key in self.weights_sd.keys():
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if key.startswith(LoRANetwork.LORA_PREFIX_TEXT_ENCODER):
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weights_has_text_encoder = True
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elif key.startswith(LoRANetwork.LORA_PREFIX_UNET):
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weights_has_unet = True
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if apply_text_encoder is None:
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apply_text_encoder = weights_has_text_encoder
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else:
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assert apply_text_encoder == weights_has_text_encoder, f"text encoder weights: {weights_has_text_encoder} but text encoder flag: {apply_text_encoder} / 重みとText Encoderのフラグが矛盾しています"
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if apply_unet is None:
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apply_unet = weights_has_unet
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else:
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assert apply_unet == weights_has_unet, f"u-net weights: {weights_has_unet} but u-net flag: {apply_unet} / 重みとU-Netのフラグが矛盾しています"
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else:
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assert apply_text_encoder is not None and apply_unet is not None, f"internal error: flag not set"
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if apply_text_encoder:
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print("enable LoRA for text encoder")
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else:
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self.text_encoder_loras = []
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if apply_unet:
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print("enable LoRA for U-Net")
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else:
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self.unet_loras = []
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for lora in self.text_encoder_loras + self.unet_loras:
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lora.apply_to()
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self.add_module(lora.lora_name, lora)
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if self.weights_sd:
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# if some weights are not in state dict, it is ok because initial LoRA does nothing (lora_up is initialized by zeros)
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info = self.load_state_dict(self.weights_sd, False)
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print(f"weights are loaded: {info}")
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def enable_gradient_checkpointing(self):
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# not supported
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pass
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def prepare_optimizer_params(self, text_encoder_lr, unet_lr):
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def enumerate_params(loras):
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params = []
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for lora in loras:
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params.extend(lora.parameters())
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return params
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self.requires_grad_(True)
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params = []
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if self.text_encoder_loras:
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param_data = {'params': enumerate_params(self.text_encoder_loras)}
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if text_encoder_lr is not None:
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param_data['lr'] = text_encoder_lr
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params.append(param_data)
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if self.unet_loras:
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param_data = {'params': enumerate_params(self.unet_loras)}
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if unet_lr is not None:
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param_data['lr'] = unet_lr
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params.append(param_data)
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return params
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def prepare_grad_etc(self, text_encoder, unet):
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self.requires_grad_(True)
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def on_epoch_start(self, text_encoder, unet):
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self.train()
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def get_trainable_params(self):
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return self.parameters()
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def save_weights(self, file, dtype, metadata):
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if metadata is not None and len(metadata) == 0:
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metadata = None
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state_dict = self.state_dict()
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if dtype is not None:
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for key in list(state_dict.keys()):
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v = state_dict[key]
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v = v.detach().clone().to("cpu").to(dtype)
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state_dict[key] = v
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if os.path.splitext(file)[1] == '.safetensors':
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from safetensors.torch import save_file
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save_file(state_dict, file, metadata)
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else:
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torch.save(state_dict, file)
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