diff --git a/networks/oft.py b/networks/oft.py
new file mode 100644
index 00000000..ba05885c
--- /dev/null
+++ b/networks/oft.py
@@ -0,0 +1,430 @@
+# OFT network module
+
+import math
+import os
+from typing import Dict, List, Optional, Tuple, Type, Union
+from diffusers import AutoencoderKL
+from transformers import CLIPTextModel
+import numpy as np
+import torch
+import re
+
+
+RE_UPDOWN = re.compile(r"(up|down)_blocks_(\d+)_(resnets|upsamplers|downsamplers|attentions)_(\d+)_")
+
+
+class OFTModule(torch.nn.Module):
+    """
+    replaces forward method of the original Linear, instead of replacing the original Linear module.
+    """
+
+    def __init__(
+        self,
+        oft_name,
+        org_module: torch.nn.Module,
+        multiplier=1.0,
+        dim=4,
+        alpha=1,
+    ):
+        """
+        dim -> num blocks
+        alpha -> constrait
+        """
+        super().__init__()
+        self.oft_name = oft_name
+
+        self.num_blocks = dim
+
+        if "Linear" in org_module.__class__.__name__:
+            out_dim = org_module.out_features
+        elif "Conv" in org_module.__class__.__name__:
+            out_dim = org_module.out_channels
+
+        if type(alpha) == torch.Tensor:
+            alpha = alpha.detach().numpy()
+        self.constraint = alpha * out_dim
+        self.register_buffer("alpha", torch.tensor(alpha))
+
+        self.block_size = out_dim // self.num_blocks
+        self.oft_blocks = torch.nn.Parameter(torch.zeros(self.num_blocks, self.block_size, self.block_size))
+
+        self.out_dim = out_dim
+        self.shape = org_module.weight.shape
+
+        self.multiplier = multiplier
+        self.org_module = [org_module]  # moduleにならないようにlistに入れる
+
+    def apply_to(self):
+        self.org_forward = self.org_module[0].forward
+        self.org_module[0].forward = self.forward
+
+    def get_weight(self, multiplier=None):
+        if multiplier is None:
+            multiplier = self.multiplier
+
+        block_Q = self.oft_blocks - self.oft_blocks.transpose(1, 2)
+        norm_Q = torch.norm(block_Q.flatten())
+        new_norm_Q = torch.clamp(norm_Q, max=self.constraint)
+        block_Q = block_Q * ((new_norm_Q + 1e-8) / (norm_Q + 1e-8))
+        I = torch.eye(self.block_size, device=self.oft_blocks.device).unsqueeze(0).repeat(self.num_blocks, 1, 1)
+        block_R = torch.matmul(I + block_Q, (I - block_Q).inverse())
+
+        block_R_weighted = self.multiplier * block_R + (1 - self.multiplier) * I
+        R = torch.block_diag(*block_R_weighted)
+
+        return R
+
+    def forward(self, x, scale=None):
+        x = self.org_forward(x)
+        if self.multiplier == 0.0:
+            return x
+
+        R = self.get_weight().to(x.device, dtype=x.dtype)
+        if x.dim() == 4:
+            x = x.permute(0, 2, 3, 1)
+            x = torch.matmul(x, R)
+            x = x.permute(0, 3, 1, 2)
+        else:
+            x = torch.matmul(x, R)
+        return x
+
+
+class OFTInfModule(OFTModule):
+    def __init__(
+        self,
+        oft_name,
+        org_module: torch.nn.Module,
+        multiplier=1.0,
+        dim=4,
+        alpha=1,
+        **kwargs,
+    ):
+        # no dropout for inference
+        super().__init__(oft_name, org_module, multiplier, dim, alpha)
+        self.enabled = True
+        self.network: OFTNetwork = None
+
+    def set_network(self, network):
+        self.network = network
+
+    def forward(self, x, scale=None):
+        if not self.enabled:
+            return self.org_forward(x)
+        return super().forward(x, scale)
+
+    def merge_to(self, multiplier=None, sign=1):
+        R = self.get_weight(multiplier) * sign
+
+        # get org weight
+        org_sd = self.org_module[0].state_dict()
+        org_weight = org_sd["weight"]
+        R = R.to(org_weight.device, dtype=org_weight.dtype)
+
+        if org_weight.dim() == 4:
+            weight = torch.einsum("oihw, op -> pihw", org_weight, R)
+        else:
+            weight = torch.einsum("oi, op -> pi", org_weight, R)
+
+        # set weight to org_module
+        org_sd["weight"] = weight
+        self.org_module[0].load_state_dict(org_sd)
+
+
+def create_network(
+    multiplier: float,
+    network_dim: Optional[int],
+    network_alpha: Optional[float],
+    vae: AutoencoderKL,
+    text_encoder: Union[CLIPTextModel, List[CLIPTextModel]],
+    unet,
+    neuron_dropout: Optional[float] = None,
+    **kwargs,
+):
+    if network_dim is None:
+        network_dim = 4  # default
+    if network_alpha is None:
+        network_alpha = 1.0
+
+    enable_all_linear = kwargs.get("enable_all_linear", None)
+    enable_conv = kwargs.get("enable_conv", None)
+    if enable_all_linear is not None:
+        enable_all_linear = bool(enable_all_linear)
+    if enable_conv is not None:
+        enable_conv = bool(enable_conv)
+
+    network = OFTNetwork(
+        text_encoder,
+        unet,
+        multiplier=multiplier,
+        dim=network_dim,
+        alpha=network_alpha,
+        enable_all_linear=enable_all_linear,
+        enable_conv=enable_conv,
+        varbose=True,
+    )
+    return network
+
+
+# Create network from weights for inference, weights are not loaded here (because can be merged)
+def create_network_from_weights(multiplier, file, vae, text_encoder, unet, weights_sd=None, for_inference=False, **kwargs):
+    if weights_sd is None:
+        if os.path.splitext(file)[1] == ".safetensors":
+            from safetensors.torch import load_file, safe_open
+
+            weights_sd = load_file(file)
+        else:
+            weights_sd = torch.load(file, map_location="cpu")
+
+    # check dim, alpha and if weights have for conv2d
+    dim = None
+    alpha = None
+    has_conv2d = None
+    all_linear = None
+    for name, param in weights_sd.items():
+        if name.endswith(".alpha"):
+            if alpha is None:
+                alpha = param.item()
+        else:
+            if dim is None:
+                dim = param.size()[0]
+            if has_conv2d is None and param.dim() == 4:
+                has_conv2d = True
+            if all_linear is None:
+                if param.dim() == 3 and "attn" not in name:
+                    all_linear = True
+        if dim is not None and alpha is not None and has_conv2d is not None:
+            break
+    if has_conv2d is None:
+        has_conv2d = False
+    if all_linear is None:
+        all_linear = False
+
+    module_class = OFTInfModule if for_inference else OFTModule
+    network = OFTNetwork(
+        text_encoder,
+        unet,
+        multiplier=multiplier,
+        dim=dim,
+        alpha=alpha,
+        enable_all_linear=all_linear,
+        enable_conv=has_conv2d,
+        module_class=module_class,
+    )
+    return network, weights_sd
+
+
+class OFTNetwork(torch.nn.Module):
+    UNET_TARGET_REPLACE_MODULE_ATTN_ONLY = ["CrossAttention"]
+    UNET_TARGET_REPLACE_MODULE_ALL_LINEAR = ["Transformer2DModel"]
+    UNET_TARGET_REPLACE_MODULE_CONV2D_3X3 = ["ResnetBlock2D", "Downsample2D", "Upsample2D"]
+    OFT_PREFIX_UNET = "oft_unet"  # これ変えないほうがいいかな
+
+    def __init__(
+        self,
+        text_encoder: Union[List[CLIPTextModel], CLIPTextModel],
+        unet,
+        multiplier: float = 1.0,
+        dim: int = 4,
+        alpha: float = 1,
+        enable_all_linear: Optional[bool] = False,
+        enable_conv: Optional[bool] = False,
+        module_class: Type[object] = OFTModule,
+        varbose: Optional[bool] = False,
+    ) -> None:
+        super().__init__()
+        self.multiplier = multiplier
+
+        self.dim = dim
+        self.alpha = alpha
+
+        print(
+            f"create OFT network. num blocks: {self.dim}, constraint: {self.alpha}, multiplier: {self.multiplier}, enable_conv: {enable_conv}"
+        )
+
+        # create module instances
+        def create_modules(
+            root_module: torch.nn.Module,
+            target_replace_modules: List[torch.nn.Module],
+        ) -> List[OFTModule]:
+            prefix = self.OFT_PREFIX_UNET
+            ofts = []
+            for name, module in root_module.named_modules():
+                if module.__class__.__name__ in target_replace_modules:
+                    for child_name, child_module in module.named_modules():
+                        is_linear = "Linear" in child_module.__class__.__name__
+                        is_conv2d = "Conv2d" in child_module.__class__.__name__
+                        is_conv2d_1x1 = is_conv2d and child_module.kernel_size == (1, 1)
+
+                        if is_linear or is_conv2d_1x1 or (is_conv2d and enable_conv):
+                            oft_name = prefix + "." + name + "." + child_name
+                            oft_name = oft_name.replace(".", "_")
+                            # print(oft_name)
+
+                            oft = module_class(
+                                oft_name,
+                                child_module,
+                                self.multiplier,
+                                dim,
+                                alpha,
+                            )
+                            ofts.append(oft)
+            return ofts
+
+        # extend U-Net target modules if conv2d 3x3 is enabled, or load from weights
+        if enable_all_linear:
+            target_modules = OFTNetwork.UNET_TARGET_REPLACE_MODULE_ALL_LINEAR
+        else:
+            target_modules = OFTNetwork.UNET_TARGET_REPLACE_MODULE_ATTN_ONLY
+        if enable_conv:
+            target_modules += OFTNetwork.UNET_TARGET_REPLACE_MODULE_CONV2D_3X3
+
+        self.unet_ofts: List[OFTModule] = create_modules(unet, target_modules)
+        print(f"create OFT for U-Net: {len(self.unet_ofts)} modules.")
+
+        # assertion
+        names = set()
+        for oft in self.unet_ofts:
+            assert oft.oft_name not in names, f"duplicated oft name: {oft.oft_name}"
+            names.add(oft.oft_name)
+
+    def set_multiplier(self, multiplier):
+        self.multiplier = multiplier
+        for oft in self.unet_ofts:
+            oft.multiplier = self.multiplier
+
+    def load_weights(self, file):
+        if os.path.splitext(file)[1] == ".safetensors":
+            from safetensors.torch import load_file
+
+            weights_sd = load_file(file)
+        else:
+            weights_sd = torch.load(file, map_location="cpu")
+
+        info = self.load_state_dict(weights_sd, False)
+        return info
+
+    def apply_to(self, text_encoder, unet, apply_text_encoder=True, apply_unet=True):
+        assert apply_unet, "apply_unet must be True"
+
+        for oft in self.unet_ofts:
+            oft.apply_to()
+            self.add_module(oft.oft_name, oft)
+
+    # マージできるかどうかを返す
+    def is_mergeable(self):
+        return True
+
+    # TODO refactor to common function with apply_to
+    def merge_to(self, text_encoder, unet, weights_sd, dtype, device):
+        print("enable OFT for U-Net")
+
+        for oft in self.unet_ofts:
+            sd_for_lora = {}
+            for key in weights_sd.keys():
+                if key.startswith(oft.oft_name):
+                    sd_for_lora[key[len(oft.oft_name) + 1 :]] = weights_sd[key]
+            oft.load_state_dict(sd_for_lora, False)
+            oft.merge_to()
+
+        print(f"weights are merged")
+
+    # 二つのText Encoderに別々の学習率を設定できるようにするといいかも
+    def prepare_optimizer_params(self, text_encoder_lr, unet_lr, default_lr):
+        self.requires_grad_(True)
+        all_params = []
+
+        def enumerate_params(ofts):
+            params = []
+            for oft in ofts:
+                params.extend(oft.parameters())
+
+            # print num of params
+            num_params = 0
+            for p in params:
+                num_params += p.numel()
+            print(f"OFT params: {num_params}")
+            return params
+
+        param_data = {"params": enumerate_params(self.unet_ofts)}
+        if unet_lr is not None:
+            param_data["lr"] = unet_lr
+        all_params.append(param_data)
+
+        return all_params
+
+    def enable_gradient_checkpointing(self):
+        # not supported
+        pass
+
+    def prepare_grad_etc(self, text_encoder, unet):
+        self.requires_grad_(True)
+
+    def on_epoch_start(self, text_encoder, unet):
+        self.train()
+
+    def get_trainable_params(self):
+        return self.parameters()
+
+    def save_weights(self, file, dtype, metadata):
+        if metadata is not None and len(metadata) == 0:
+            metadata = None
+
+        state_dict = self.state_dict()
+
+        if dtype is not None:
+            for key in list(state_dict.keys()):
+                v = state_dict[key]
+                v = v.detach().clone().to("cpu").to(dtype)
+                state_dict[key] = v
+
+        if os.path.splitext(file)[1] == ".safetensors":
+            from safetensors.torch import save_file
+            from library import train_util
+
+            # Precalculate model hashes to save time on indexing
+            if metadata is None:
+                metadata = {}
+            model_hash, legacy_hash = train_util.precalculate_safetensors_hashes(state_dict, metadata)
+            metadata["sshs_model_hash"] = model_hash
+            metadata["sshs_legacy_hash"] = legacy_hash
+
+            save_file(state_dict, file, metadata)
+        else:
+            torch.save(state_dict, file)
+
+    def backup_weights(self):
+        # 重みのバックアップを行う
+        ofts: List[OFTInfModule] = self.unet_ofts
+        for oft in ofts:
+            org_module = oft.org_module[0]
+            if not hasattr(org_module, "_lora_org_weight"):
+                sd = org_module.state_dict()
+                org_module._lora_org_weight = sd["weight"].detach().clone()
+                org_module._lora_restored = True
+
+    def restore_weights(self):
+        # 重みのリストアを行う
+        ofts: List[OFTInfModule] = self.unet_ofts
+        for oft in ofts:
+            org_module = oft.org_module[0]
+            if not org_module._lora_restored:
+                sd = org_module.state_dict()
+                sd["weight"] = org_module._lora_org_weight
+                org_module.load_state_dict(sd)
+                org_module._lora_restored = True
+
+    def pre_calculation(self):
+        # 事前計算を行う
+        ofts: List[OFTInfModule] = self.unet_ofts
+        for oft in ofts:
+            org_module = oft.org_module[0]
+            oft.merge_to()
+            # sd = org_module.state_dict()
+            # org_weight = sd["weight"]
+            # lora_weight = oft.get_weight().to(org_weight.device, dtype=org_weight.dtype)
+            # sd["weight"] = org_weight + lora_weight
+            # assert sd["weight"].shape == org_weight.shape
+            # org_module.load_state_dict(sd)
+
+            org_module._lora_restored = False
+            oft.enabled = False