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| # Copyright 2023-present the HuggingFace Inc. team. | |
| # | |
| # Licensed under the Apache License, Version 2.0 (the "License"); | |
| # you may not use this file except in compliance with the License. | |
| # You may obtain a copy of the License at | |
| # | |
| # http://www.apache.org/licenses/LICENSE-2.0 | |
| # | |
| # Unless required by applicable law or agreed to in writing, software | |
| # distributed under the License is distributed on an "AS IS" BASIS, | |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| # See the License for the specific language governing permissions and | |
| # limitations under the License. | |
| from __future__ import annotations | |
| import math | |
| import warnings | |
| from typing import Any, Optional, Union | |
| import torch | |
| import torch.nn as nn | |
| import torch.nn.functional as F | |
| from transformers.pytorch_utils import Conv1D | |
| from peft.tuners.tuners_utils import BaseTunerLayer, check_adapters_to_merge | |
| from peft.utils.integrations import dequantize_bnb_weight, gather_params_ctx | |
| from peft.utils.other import transpose | |
| from .config import LoraConfig | |
| from einops import rearrange | |
| class LoraLayer(BaseTunerLayer): | |
| # All names of layers that may contain (trainable) adapter weights | |
| adapter_layer_names = ("lora_A", "lora_B", "lora_embedding_A", "lora_embedding_B") | |
| # All names of other parameters that may contain adapter-related parameters | |
| other_param_names = ("r", "lora_alpha", "scaling", "lora_dropout") | |
| def __init__(self, base_layer: nn.Module, **kwargs) -> None: | |
| self.base_layer = base_layer | |
| self.r = {} | |
| self.lora_alpha = {} | |
| self.scaling = {} | |
| self.lora_dropout = nn.ModuleDict({}) | |
| self.lora_A = nn.ModuleDict({}) | |
| self.lora_B = nn.ModuleDict({}) | |
| # For Embedding layer | |
| self.lora_embedding_A = nn.ParameterDict({}) | |
| self.lora_embedding_B = nn.ParameterDict({}) | |
| # Mark the weight as unmerged | |
| self._disable_adapters = False | |
| self.merged_adapters = [] | |
| self.use_dora: dict[str, bool] = {} | |
| self.lora_magnitude_vector: Optional[torch.nn.ParameterDict] = None # for DoRA | |
| self._caches: dict[str, Any] = {} | |
| self.kwargs = kwargs | |
| base_layer = self.get_base_layer() | |
| if isinstance(base_layer, nn.Linear): | |
| in_features, out_features = base_layer.in_features, base_layer.out_features | |
| elif isinstance(base_layer, nn.Conv2d): | |
| in_features, out_features = base_layer.in_channels, base_layer.out_channels | |
| elif isinstance(base_layer, nn.Embedding): | |
| in_features, out_features = base_layer.num_embeddings, base_layer.embedding_dim | |
| elif isinstance(base_layer, Conv1D): | |
| in_features, out_features = ( | |
| base_layer.weight.ds_shape if hasattr(base_layer.weight, "ds_shape") else base_layer.weight.shape | |
| ) | |
| elif hasattr(base_layer, "infeatures") and hasattr(base_layer, "outfeatures"): | |
| # QuantLinear | |
| in_features, out_features = base_layer.infeatures, base_layer.outfeatures | |
| elif hasattr(base_layer, "input_size") and hasattr(base_layer, "output_size"): | |
| # Megatron ColumnParallelLinear,RowParallelLinear | |
| in_features, out_features = base_layer.input_size, base_layer.output_size | |
| elif hasattr(base_layer, "codebooks") and base_layer.__class__.__name__ == "QuantizedLinear": | |
| # AQLM QuantLinear | |
| in_features, out_features = base_layer.in_features, base_layer.out_features | |
| elif hasattr(base_layer, "w_bit") and base_layer.__class__.__name__ == "WQLinear_GEMM": | |
| # Awq layers | |
| in_features, out_features = base_layer.in_features, base_layer.out_features | |
| else: | |
| raise ValueError(f"Unsupported layer type {type(base_layer)}") | |
| self.in_features = in_features | |
| self.out_features = out_features | |
| def update_layer( | |
| self, adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora: bool = False | |
| ): | |
| # This code works for linear layers, override for other layer types | |
| if r <= 0: | |
| raise ValueError(f"`r` should be a positive integer value but the value passed is {r}") | |
| self.r[adapter_name] = r | |
| self.lora_alpha[adapter_name] = lora_alpha | |
| if lora_dropout > 0.0: | |
| lora_dropout_layer = nn.Dropout(p=lora_dropout) | |
| else: | |
| lora_dropout_layer = nn.Identity() | |
| self.lora_dropout.update(nn.ModuleDict({adapter_name: lora_dropout_layer})) | |
| # Actual trainable parameters | |
| self.lora_A[adapter_name] = nn.Linear(self.in_features, r, bias=False) | |
| self.lora_B[adapter_name] = nn.Linear(r, self.out_features, bias=False) | |
| if use_rslora: | |
| self.scaling[adapter_name] = lora_alpha / math.sqrt(r) | |
| else: | |
| self.scaling[adapter_name] = lora_alpha / r | |
| if init_lora_weights == "loftq": | |
| self.loftq_init(adapter_name) | |
| elif init_lora_weights: | |
| self.reset_lora_parameters(adapter_name, init_lora_weights) | |
| # check weight and qweight (for GPTQ) | |
| for weight_name in ("weight", "qweight"): | |
| weight = getattr(self.get_base_layer(), weight_name, None) | |
| if weight is not None: | |
| # the layer is already completely initialized, this is an update | |
| if weight.dtype.is_floating_point or weight.dtype.is_complex: | |
| self.to(weight.device, dtype=weight.dtype) | |
| else: | |
| self.to(weight.device) | |
| break | |
| if use_dora: | |
| self.dora_init(adapter_name) | |
| self.use_dora[adapter_name] = True | |
| else: | |
| self.use_dora[adapter_name] = False | |
| self.set_adapter(self.active_adapters) | |
| def reset_lora_parameters(self, adapter_name, init_lora_weights): | |
| if init_lora_weights is False: | |
| return | |
| if adapter_name in self.lora_A.keys(): | |
| if init_lora_weights is True: | |
| # initialize A the same way as the default for nn.Linear and B to zero | |
| # https://github.com/microsoft/LoRA/blob/a0a92e0f26c067cf94747bdbf1ce73793fa44d19/loralib/layers.py#L124 | |
| nn.init.kaiming_uniform_(self.lora_A[adapter_name].weight, a=math.sqrt(5)) | |
| elif init_lora_weights.lower() == "gaussian": | |
| nn.init.normal_(self.lora_A[adapter_name].weight, std=1 / self.r[adapter_name]) | |
| else: | |
| raise ValueError(f"Unknown initialization {init_lora_weights=}") | |
| nn.init.zeros_(self.lora_B[adapter_name].weight) | |
| if adapter_name in self.lora_embedding_A.keys(): | |
| # initialize a the same way as the default for nn.linear and b to zero | |
| nn.init.zeros_(self.lora_embedding_A[adapter_name]) | |
| nn.init.normal_(self.lora_embedding_B[adapter_name]) | |
| def loftq_init(self, adapter_name): | |
| from peft.utils.loftq_utils import loftq_init | |
| weight = self.get_base_layer().weight | |
| kwargs = { | |
| "num_bits": self.kwargs.get("loftq_bits", 4), | |
| "reduced_rank": self.r[adapter_name], | |
| "num_iter": self.kwargs.get("loftq_iter", 1), | |
| } | |
| qweight, lora_A, lora_B = loftq_init(weight, **kwargs) | |
| if adapter_name in self.lora_A.keys(): | |
| # initialize A the same way as the default for nn.Linear and B to zero | |
| self.lora_A[adapter_name].weight.data = lora_A | |
| self.lora_B[adapter_name].weight.data = lora_B | |
| if adapter_name in self.lora_embedding_A.keys(): | |
| # initialize a the same way as the default for nn.linear and b to zero | |
| self.lora_embedding_A[adapter_name].weight.data = lora_A | |
| self.lora_embedding_B[adapter_name].weight.data = lora_B | |
| self.get_base_layer().weight.data = qweight | |
| def _get_weight_norm(self, weight, lora_weight, scaling) -> torch.Tensor: | |
| # calculate L2 norm of weight matrix, column-wise | |
| weight = weight + scaling * lora_weight | |
| weight_norm = torch.linalg.norm(weight, dim=1).to(weight.dtype) | |
| return weight_norm | |
| def dora_init(self, adapter_name: str) -> None: | |
| lora_A = self.lora_A[adapter_name] | |
| lora_B = self.lora_B[adapter_name] | |
| scaling = self.scaling[adapter_name] | |
| with gather_params_ctx(self.get_base_layer()): | |
| weight = self.get_base_layer().weight | |
| quant_state = getattr(self.get_base_layer(), "state", None) | |
| weight = dequantize_bnb_weight(weight, state=quant_state) # no-op if not bnb | |
| if weight.data.ndim == 4: # For handling LoRAs applied to Conv2Ds. | |
| lora_weight = torch.mm(lora_B.weight.flatten(start_dim=1), lora_A.weight.flatten(start_dim=1)) | |
| lora_weight = lora_weight.reshape(weight.shape) | |
| else: | |
| lora_weight = lora_B.weight @ lora_A.weight | |
| weight_norm = self._get_weight_norm(weight, lora_weight, scaling) | |
| self.lora_magnitude_vector = nn.ParameterDict() | |
| self.lora_magnitude_vector[adapter_name] = nn.Parameter(weight_norm, requires_grad=True) | |
| # add lora_magnitude_vector to the list of learnable parameters | |
| self.adapter_layer_names = self.adapter_layer_names[:] + ("lora_magnitude_vector",) | |
| def _cache_store(self, key: str, value: Any) -> None: | |
| self._caches[key] = value | |
| def _cache_pop(self, key: str) -> Any: | |
| value = self._caches.pop(key) | |
| return value | |
| def _apply_dora(self, x, lora_A, lora_B, scaling, active_adapter): | |
| """ | |
| For DoRA, calculate the extra output from LoRA with DoRA applied. This should be added on top of the base layer | |
| output. | |
| """ | |
| lora_weight = lora_B.weight @ lora_A.weight | |
| magnitude = self.lora_magnitude_vector[active_adapter] | |
| weight = self.get_base_layer().weight | |
| quant_state = getattr(self.get_base_layer(), "state", None) | |
| weight = dequantize_bnb_weight(weight, state=quant_state) # no-op if not bnb | |
| weight = weight.to(x.dtype) | |
| weight_norm = self._get_weight_norm(weight, lora_weight, scaling) | |
| # see section 4.3 of DoRA (https://arxiv.org/abs/2402.09353) | |
| # "[...] we suggest treating ||V +∆V ||_c in | |
| # Eq. (5) as a constant, thereby detaching it from the gradient | |
| # graph. This means that while ||V + ∆V ||_c dynamically | |
| # reflects the updates of ∆V , it won’t receive any gradient | |
| # during backpropagation" | |
| weight_norm = weight_norm.detach() | |
| mag_norm_scale = (magnitude / weight_norm).view(1, -1) | |
| result_dora = (mag_norm_scale - 1) * ( | |
| F.linear(x, transpose(weight, self.fan_in_fan_out)) | |
| ) + mag_norm_scale * lora_B(lora_A(x)) * scaling | |
| # Note: Computation could potentially be accelerated by using the code below instead of calculating X@W again. | |
| # This is only correct if dropout=0, otherwise results will differ: | |
| # https://github.com/huggingface/peft/pull/1474#issuecomment-1964682771 | |
| # bias = self.get_base_layer().bias | |
| # if bias is not None: | |
| # result = result - bias | |
| # result = mag_norm_scale * result + mag_norm_scale * lora_B(lora_A(x)) * scaling | |
| # if bias is not None: | |
| # result = result + bias | |
| return result_dora | |
| def set_scale(self, adapter, scale): | |
| if adapter not in self.scaling: | |
| # Ignore the case where the adapter is not in the layer | |
| return | |
| self.scaling[adapter] = scale * self.lora_alpha[adapter] / self.r[adapter] | |
| def scale_layer(self, scale: float) -> None: | |
| if scale == 1: | |
| return | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| self.scaling[active_adapter] *= scale | |
| def unscale_layer(self, scale=None) -> None: | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| if scale is None: | |
| self.scaling[active_adapter] = self.lora_alpha[active_adapter] / self.r[active_adapter] | |
| else: | |
| self.scaling[active_adapter] /= scale | |
| def _check_forward_args(self, x, *args, **kwargs): | |
| """Check if the arguments are compatible with the configs and state of the model""" | |
| adapter_names = kwargs.get("adapter_names", None) | |
| if adapter_names is None: | |
| return | |
| if len(x) != len(adapter_names): | |
| msg = ( | |
| "Length of `adapter_names` should be the same as the number of inputs, but got " | |
| f"{len(adapter_names)} and {len(x)} respectively." | |
| ) | |
| raise ValueError(msg) | |
| if self.merged: | |
| # It is unclear what would be the right thing to do if users pass adapter_names and there are merged | |
| # adapters. Therefore, it is better to raise an error in this case. | |
| msg = "Cannot pass `adapter_names` when there are merged adapters, please call `unmerge_adapter` first." | |
| raise ValueError(msg) | |
| unique_adapters = set(self.active_adapters) | |
| for adapter_name in unique_adapters: | |
| if self.use_dora.get(adapter_name, False): | |
| msg = "Cannot pass `adapter_names` when DoRA is enabled." | |
| raise ValueError(msg) | |
| def _mixed_batch_forward( | |
| self, x: torch.Tensor, *args: Any, adapter_names: list[str], **kwargs: Any | |
| ) -> torch.Tensor: | |
| # This is a special method that handles the case when users pass the argument `adapter_names`. This is an | |
| # extra argument that allows mixing different adapters in the same batch at inference time. | |
| result = self.base_layer(x, *args, **kwargs) | |
| torch_result_dtype = result.dtype | |
| unique_adapters = set(adapter_names) | |
| sub_batch_indices_list = [] | |
| for adapter in unique_adapters: | |
| sub_batch_indices_list.append([index for index, item in enumerate(adapter_names) if item == adapter]) | |
| for i, active_adapter in enumerate(unique_adapters): | |
| if active_adapter == "__base__": | |
| continue | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| lora_A = self.lora_A[active_adapter] | |
| lora_B = self.lora_B[active_adapter] | |
| dropout = self.lora_dropout[active_adapter] | |
| scaling = self.scaling[active_adapter] | |
| # getting the sub-batch, passing it to LoRA layers and updating the corresponding indices of the linear | |
| # layer output | |
| sub_batch = x[sub_batch_indices_list[i]].to(lora_A.weight.dtype) | |
| lora_output = lora_B(lora_A(dropout(sub_batch))) * scaling | |
| result[sub_batch_indices_list[i]] += lora_output.to(torch_result_dtype) | |
| return result | |
| # Below code is based on https://github.com/microsoft/LoRA/blob/main/loralib/layers.py | |
| # and modified to work with PyTorch FSDP | |
| # ------------------------------------------------------------------------------------------ | |
| # Copyright (c) Microsoft Corporation. All rights reserved. | |
| # Licensed under the MIT License (MIT). See LICENSE in the repo root for license information. | |
| # ------------------------------------------------------------------------------------------ | |
| class Linear(nn.Module, LoraLayer): | |
| # Lora implemented in a dense layer | |
| def __init__( | |
| self, | |
| base_layer, | |
| adapter_name: str, | |
| r: int = 0, | |
| lora_alpha: int = 1, | |
| lora_dropout: float = 0.0, | |
| fan_in_fan_out: bool = False, # Set this to True if the layer to replace stores weight like (fan_in, fan_out) | |
| is_target_conv_1d_layer: bool = False, | |
| init_lora_weights: Union[bool, str] = True, | |
| use_rslora: bool = False, | |
| use_dora: bool = False, | |
| **kwargs, | |
| ) -> None: | |
| super().__init__() | |
| LoraLayer.__init__(self, base_layer, **kwargs) | |
| self.fan_in_fan_out = fan_in_fan_out | |
| self._active_adapter = adapter_name | |
| self.update_layer( | |
| adapter_name, | |
| r, | |
| lora_alpha=lora_alpha, | |
| lora_dropout=lora_dropout, | |
| init_lora_weights=init_lora_weights, | |
| use_rslora=use_rslora, | |
| use_dora=use_dora, | |
| ) | |
| self.is_target_conv_1d_layer = is_target_conv_1d_layer | |
| def merge(self, safe_merge: bool = False, adapter_names: Optional[list[str]] = None) -> None: | |
| """ | |
| Merge the active adapter weights into the base weights | |
| Args: | |
| safe_merge (`bool`, *optional*): | |
| If True, the merge operation will be performed in a copy of the original weights and check for NaNs | |
| before merging the weights. This is useful if you want to check if the merge operation will produce | |
| NaNs. Defaults to `False`. | |
| adapter_names (`list[str]`, *optional*): | |
| The list of adapter names that should be merged. If None, all active adapters will be merged. Defaults | |
| to `None`. | |
| """ | |
| adapter_names = check_adapters_to_merge(self, adapter_names) | |
| if not adapter_names: | |
| # no adapter to merge | |
| return | |
| for active_adapter in adapter_names: | |
| if active_adapter in self.lora_A.keys(): | |
| base_layer = self.get_base_layer() | |
| if safe_merge: | |
| # Note that safe_merge will be slower than the normal merge | |
| # because of the copy operation. | |
| orig_weights = base_layer.weight.data.clone() | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| orig_weights = orig_weights + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(orig_weights, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| orig_weights = dora_factor.view(-1, 1) * (orig_weights + delta_weight) | |
| if not torch.isfinite(orig_weights).all(): | |
| raise ValueError( | |
| f"NaNs detected in the merged weights. The adapter {active_adapter} seems to be broken" | |
| ) | |
| base_layer.weight.data = orig_weights | |
| else: | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| base_layer.weight.data = base_layer.weight.data + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(base_layer.weight, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| new_weight = dora_factor.view(-1, 1) * (base_layer.weight.data + delta_weight) | |
| base_layer.weight.data = new_weight | |
| self.merged_adapters.append(active_adapter) | |
| def unmerge(self) -> None: | |
| """ | |
| This method unmerges all merged adapter layers from the base weights. | |
| """ | |
| if not self.merged: | |
| warnings.warn("Already unmerged. Nothing to do.") | |
| return | |
| while len(self.merged_adapters) > 0: | |
| active_adapter = self.merged_adapters.pop() | |
| if active_adapter in self.lora_A.keys(): | |
| weight = self.get_base_layer().weight | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| weight.data -= delta_weight | |
| else: | |
| weight_norm = self._cache_pop(f"{active_adapter}-weight_norm") | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| weight_orig = weight.data / dora_factor.view(-1, 1) - delta_weight | |
| weight.data = weight_orig | |
| def get_delta_weight(self, adapter) -> torch.Tensor: | |
| """ | |
| Compute the delta weight for the given adapter. | |
| Args: | |
| adapter (str): | |
| The name of the adapter for which the delta weight should be computed. | |
| """ | |
| device = self.lora_B[adapter].weight.device | |
| dtype = self.lora_B[adapter].weight.dtype | |
| # In case users wants to merge the adapter weights that are in | |
| # float16 while being on CPU, we need to cast the weights to float32, perform the merge and then cast back to | |
| # float16 because the `@` and matmul operation in general is not supported in torch + cpu + fp16. | |
| cast_to_fp32 = device.type == "cpu" and dtype == torch.float16 | |
| weight_A = self.lora_A[adapter].weight | |
| weight_B = self.lora_B[adapter].weight | |
| if cast_to_fp32: | |
| weight_A = weight_A.float() | |
| weight_B = weight_B.float() | |
| output_tensor = transpose(weight_B @ weight_A, self.fan_in_fan_out) * self.scaling[adapter] | |
| if cast_to_fp32: | |
| output_tensor = output_tensor.to(dtype=dtype) | |
| # cast back the weights | |
| self.lora_A[adapter].weight.data = weight_A.to(dtype) | |
| self.lora_B[adapter].weight.data = weight_B.to(dtype) | |
| return output_tensor | |
| def forward(self, x: torch.Tensor, *args: Any, **kwargs: Any) -> torch.Tensor: | |
| self._check_forward_args(x, *args, **kwargs) | |
| adapter_names = kwargs.pop("adapter_names", None) | |
| if self.disable_adapters: | |
| if self.merged: | |
| self.unmerge() | |
| result = self.base_layer(x, *args, **kwargs) | |
| elif adapter_names is not None: | |
| result = self._mixed_batch_forward(x, *args, adapter_names=adapter_names, **kwargs) | |
| elif self.merged: | |
| result = self.base_layer(x, *args, **kwargs) | |
| else: | |
| result = self.base_layer(x, *args, **kwargs) | |
| torch_result_dtype = result.dtype | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| lora_A = self.lora_A[active_adapter] | |
| lora_B = self.lora_B[active_adapter] | |
| dropout = self.lora_dropout[active_adapter] | |
| scaling = self.scaling[active_adapter] | |
| x = x.to(lora_A.weight.dtype) | |
| if not self.use_dora[active_adapter]: | |
| result = result + lora_B(lora_A(dropout(x))) * scaling | |
| else: | |
| x = dropout(x) | |
| result = result + self._apply_dora(x, lora_A, lora_B, scaling, active_adapter) | |
| result = result.to(torch_result_dtype) | |
| return result | |
| def __repr__(self) -> str: | |
| rep = super().__repr__() | |
| return "lora." + rep | |
| class Embedding(nn.Module, LoraLayer): | |
| # LoRA implemented in a Embedding layer | |
| def __init__( | |
| self, | |
| base_layer: nn.Module, | |
| adapter_name: str, | |
| r: int = 0, | |
| lora_alpha: int = 1, | |
| lora_dropout: float = 0.0, | |
| init_lora_weights: Union[bool, str] = True, | |
| use_rslora: bool = False, | |
| use_dora: bool = False, | |
| **kwargs, | |
| ) -> None: | |
| super().__init__() | |
| LoraLayer.__init__(self, base_layer) | |
| if use_dora: | |
| raise ValueError(f"{self.__class__.__name__} does not support DoRA yet, please set it to False") | |
| self._active_adapter = adapter_name | |
| self.update_layer( | |
| adapter_name, | |
| r, | |
| lora_alpha=lora_alpha, | |
| lora_dropout=lora_dropout, | |
| init_lora_weights=init_lora_weights, | |
| use_rslora=use_rslora, | |
| use_dora=use_dora, | |
| ) | |
| def update_layer(self, adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora): | |
| if r <= 0: | |
| raise ValueError(f"`r` should be a positive integer value but the value passed is {r}") | |
| self.r[adapter_name] = r | |
| self.lora_alpha[adapter_name] = lora_alpha | |
| if lora_dropout > 0.0: | |
| lora_dropout_layer = nn.Dropout(p=lora_dropout) | |
| else: | |
| lora_dropout_layer = nn.Identity() | |
| self.lora_dropout[adapter_name] = lora_dropout_layer | |
| # Actual trainable parameters | |
| weight_A = torch.randn((r, self.in_features)) | |
| weight_B = torch.randn((self.out_features, r)) | |
| self.lora_embedding_A[adapter_name] = nn.Parameter(weight_A) | |
| self.lora_embedding_B[adapter_name] = nn.Parameter(weight_B) | |
| if use_rslora: | |
| self.scaling[adapter_name] = lora_alpha / math.sqrt(r) | |
| else: | |
| self.scaling[adapter_name] = lora_alpha / r | |
| if init_lora_weights == "loftq": | |
| self.loftq_init(adapter_name) | |
| elif init_lora_weights: | |
| self.reset_lora_parameters(adapter_name, init_lora_weights) | |
| base_layer = self.get_base_layer() | |
| weight = getattr(base_layer, "weight", None) | |
| if weight is not None: | |
| # the layer is already completely initialized, this is an update | |
| self.to(base_layer.weight.device, dtype=weight.dtype) | |
| self.set_adapter(self.active_adapters) | |
| def merge(self, safe_merge: bool = False, adapter_names: Optional[list[str]] = None) -> None: | |
| """ | |
| Merge the active adapter weights into the base weights | |
| Args: | |
| safe_merge (`bool`, *optional*): | |
| If True, the merge operation will be performed in a copy of the original weights and check for NaNs | |
| before merging the weights. This is useful if you want to check if the merge operation will produce | |
| NaNs. Defaults to `False`. | |
| adapter_names (`list[str]`, *optional*): | |
| The list of adapter names that should be merged. If None, all active adapters will be merged. Defaults | |
| to `None`. | |
| """ | |
| adapter_names = check_adapters_to_merge(self, adapter_names) | |
| if not adapter_names: | |
| # no adapter to merge | |
| return | |
| for active_adapter in adapter_names: | |
| if active_adapter in self.lora_embedding_A.keys(): | |
| base_layer = self.get_base_layer() | |
| if safe_merge: | |
| # Note that safe_merge will be slower than the normal merge | |
| # because of the copy operation. | |
| orig_weights = base_layer.weight.data.clone() | |
| orig_weights = orig_weights + self.get_delta_weight(active_adapter) | |
| if not torch.isfinite(orig_weights).all(): | |
| raise ValueError( | |
| f"NaNs detected in the merged weights. The adapter {active_adapter} seems to be broken" | |
| ) | |
| base_layer.weight.data = orig_weights | |
| else: | |
| base_layer.weight.data = base_layer.weight.data + self.get_delta_weight(active_adapter) | |
| self.merged_adapters.append(active_adapter) | |
| def unmerge(self) -> None: | |
| """ | |
| This method unmerges all merged adapter layers from the base weights. | |
| """ | |
| if not self.merged: | |
| warnings.warn("Already unmerged. Nothing to do.") | |
| return | |
| while len(self.merged_adapters) > 0: | |
| active_adapter = self.merged_adapters.pop() | |
| if active_adapter in self.lora_embedding_A.keys(): | |
| self.get_base_layer().weight.data -= self.get_delta_weight(active_adapter) | |
| def get_delta_weight(self, adapter) -> torch.Tensor: | |
| """ | |
| Compute the delta weight for the given adapter. | |
| Args: | |
| adapter (str): | |
| The name of the adapter for which the delta weight should be computed. | |
| """ | |
| device = self.lora_embedding_B[adapter].device | |
| dtype = self.lora_embedding_A[adapter].dtype | |
| # In case users wants to merge the adapter weights that are in | |
| # float16 while being on CPU, we need to cast the weights to float32, perform the merge and then cast back to | |
| # float16 because the `@` and matmul operation in general is not supported in torch + cpu + fp16. | |
| cast_to_fp32 = device.type == "cpu" and dtype == torch.float16 | |
| weight_A = self.lora_embedding_A[adapter] | |
| weight_B = self.lora_embedding_B[adapter] | |
| if cast_to_fp32: | |
| weight_A = weight_A.float() | |
| weight_B = weight_B.float() | |
| output_tensor = transpose(weight_B @ weight_A, True) * self.scaling[adapter] | |
| if cast_to_fp32: | |
| output_tensor = output_tensor.to(dtype=dtype) | |
| # cast back the weights | |
| self.lora_embedding_A[adapter] = weight_A.to(dtype) | |
| self.lora_embedding_B[adapter] = weight_B.to(dtype) | |
| return output_tensor | |
| def _mixed_batch_forward( | |
| self, x: torch.Tensor, *args: Any, adapter_names: list[str], **kwargs: Any | |
| ) -> torch.Tensor: | |
| # This is a special method that handles the case when users pass the argument `adapter_names`. This is an | |
| # extra argument that allows mixing different adapters in the same batch at inference time. | |
| result = self.base_layer(x, *args, **kwargs) | |
| unique_adapters = set(adapter_names) | |
| sub_batch_indices_list = [] | |
| for adapter in unique_adapters: | |
| sub_batch_indices_list.append([index for index, item in enumerate(adapter_names) if item == adapter]) | |
| for i, active_adapter in enumerate(unique_adapters): | |
| if active_adapter == "__base__": | |
| continue | |
| if active_adapter not in self.lora_embedding_A.keys(): | |
| continue | |
| embedding_A = self.lora_embedding_A[active_adapter].T | |
| embedding_B = self.lora_embedding_B[active_adapter].T | |
| scaling = self.scaling[active_adapter] | |
| # getting the sub-batch, passing it to LoRA layers and updating the corresponding indices of the linear | |
| # layer output | |
| sub_batch = x[sub_batch_indices_list[i]] | |
| after_A = self._embed(sub_batch, embedding_A) | |
| result[sub_batch_indices_list[i]] += (after_A @ embedding_B) * scaling | |
| return result | |
| def _embed(self, input: torch.Tensor, weight: torch.Tensor) -> torch.Tensor: | |
| base_layer = self.get_base_layer() | |
| return F.embedding( | |
| input, | |
| weight, | |
| padding_idx=base_layer.padding_idx, | |
| max_norm=base_layer.max_norm, | |
| norm_type=base_layer.norm_type, | |
| scale_grad_by_freq=base_layer.scale_grad_by_freq, | |
| sparse=base_layer.sparse, | |
| ) | |
| def forward(self, x: torch.Tensor, *args: Any, **kwargs: Any) -> torch.Tensor: | |
| # TODO: no dtype conversion here, unlike in Linear, is that correct? | |
| self._check_forward_args(x, *args, **kwargs) | |
| adapter_names = kwargs.pop("adapter_names", None) | |
| if self.disable_adapters: | |
| if self.merged: | |
| self.unmerge() | |
| result = self.base_layer(x, *args, **kwargs) | |
| elif adapter_names is not None: | |
| result = self._mixed_batch_forward(x, *args, adapter_names=adapter_names, **kwargs) | |
| elif self.merged: | |
| result = self.base_layer(x, *args, **kwargs) | |
| else: | |
| result = self.base_layer(x, *args, **kwargs) | |
| torch_result_dtype = result.dtype | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_embedding_A: | |
| continue | |
| embedding_A = self.lora_embedding_A[active_adapter].T | |
| embedding_B = self.lora_embedding_B[active_adapter].T | |
| scaling = self.scaling[active_adapter] | |
| after_A = self._embed(x, embedding_A) | |
| result = result + (after_A @ embedding_B) * scaling | |
| result = result.to(torch_result_dtype) | |
| return result | |
| def __repr__(self) -> str: | |
| rep = super().__repr__() | |
| return "lora." + rep | |
| class Conv2d(nn.Module, LoraLayer): | |
| # Lora implemented in a conv2d layer | |
| def __init__( | |
| self, | |
| base_layer: nn.Module, | |
| adapter_name: str, | |
| r: int = 0, | |
| lora_alpha: int = 1, | |
| lora_dropout: float = 0.0, | |
| init_lora_weights: Union[bool, str] = True, | |
| use_rslora: bool = False, | |
| use_dora: bool = False, | |
| **kwargs, | |
| ) -> None: | |
| super().__init__() | |
| LoraLayer.__init__(self, base_layer) | |
| self._active_adapter = adapter_name | |
| self.update_layer( | |
| adapter_name, | |
| r, | |
| lora_alpha=lora_alpha, | |
| lora_dropout=lora_dropout, | |
| init_lora_weights=init_lora_weights, | |
| use_rslora=use_rslora, | |
| use_dora=use_dora, | |
| ) | |
| def update_layer(self, adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora): | |
| if r <= 0: | |
| raise ValueError(f"`r` should be a positive integer value but the value passed is {r}") | |
| self.r[adapter_name] = r | |
| self.lora_alpha[adapter_name] = lora_alpha | |
| if lora_dropout > 0.0: | |
| lora_dropout_layer = nn.Dropout(p=lora_dropout) | |
| else: | |
| lora_dropout_layer = nn.Identity() | |
| self.lora_dropout[adapter_name] = lora_dropout_layer | |
| # Actual trainable parameters | |
| base_layer = self.get_base_layer() | |
| kernel_size = base_layer.kernel_size | |
| stride = base_layer.stride | |
| padding = base_layer.padding | |
| self.lora_A[adapter_name] = nn.Conv2d(self.in_features, r, kernel_size, stride, padding, bias=False) | |
| self.lora_B[adapter_name] = nn.Conv2d(r, self.out_features, (1, 1), (1, 1), bias=False) | |
| if use_rslora: | |
| self.scaling[adapter_name] = lora_alpha / math.sqrt(r) | |
| else: | |
| self.scaling[adapter_name] = lora_alpha / r | |
| if init_lora_weights == "loftq": | |
| self.loftq_init(adapter_name) | |
| elif init_lora_weights: | |
| self.reset_lora_parameters(adapter_name, init_lora_weights) | |
| weight = getattr(base_layer, "weight", None) | |
| if weight is not None: | |
| # the layer is already completely initialized, this is an update | |
| self.to(base_layer.weight.device, dtype=weight.dtype) | |
| if use_dora: | |
| self.dora_init(adapter_name) | |
| self.use_dora[adapter_name] = True | |
| else: | |
| self.use_dora[adapter_name] = False | |
| self.set_adapter(self.active_adapters) | |
| def merge(self, safe_merge: bool = False, adapter_names: Optional[list[str]] = None) -> None: | |
| """ | |
| Merge the active adapter weights inside the base weights | |
| Args: | |
| safe_merge (`bool`, *optional*): | |
| If True, the merge operation will be performed in a copy of the original weights and check for NaNs | |
| before merging the weights. This is useful if you want to check if the merge operation will produce | |
| NaNs. Defaults to `False`. | |
| adapter_names (`list[str]`, *optional*): | |
| The list of adapter names that should be merged. If None, all active adapters will be merged. Defaults | |
| to `None`. | |
| """ | |
| adapter_names = check_adapters_to_merge(self, adapter_names) | |
| if not adapter_names: | |
| # no adapter to merge | |
| return | |
| for active_adapter in adapter_names: | |
| if active_adapter in self.lora_A.keys(): | |
| base_layer = self.get_base_layer() | |
| if safe_merge: | |
| # Note that safe_merge will be slower than the normal merge | |
| # because of the copy operation. | |
| orig_weights = base_layer.weight.data.clone() | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| orig_weights = orig_weights + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(orig_weights, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| orig_weights = dora_factor.view(-1, 1, 1, 1) * (orig_weights + delta_weight) | |
| if not torch.isfinite(orig_weights).all(): | |
| raise ValueError( | |
| f"NaNs detected in the merged weights. The adapter {active_adapter} seems to be broken" | |
| ) | |
| base_layer.weight.data = orig_weights | |
| else: | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| base_layer.weight.data = base_layer.weight.data + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(base_layer.weight, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| new_weight = dora_factor.view(-1, 1, 1, 1) * (base_layer.weight.data + delta_weight) | |
| base_layer.weight.data = new_weight | |
| self.merged_adapters.append(active_adapter) | |
| def unmerge(self) -> None: | |
| """ | |
| This method unmerges all merged adapter layers from the base weights. | |
| """ | |
| if not self.merged: | |
| warnings.warn("Already unmerged. Nothing to do.") | |
| return | |
| while len(self.merged_adapters) > 0: | |
| active_adapter = self.merged_adapters.pop() | |
| if active_adapter in self.lora_A.keys(): | |
| weight = self.get_base_layer().weight | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| weight.data -= delta_weight | |
| else: | |
| weight_norm = self._cache_pop(f"{active_adapter}-weight_norm") | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| weight_orig = weight.data / dora_factor.view(-1, 1, 1, 1) - delta_weight | |
| weight.data = weight_orig | |
| def get_delta_weight(self, adapter) -> torch.Tensor: | |
| """ | |
| Compute the delta weight for the given adapter. | |
| Args: | |
| adapter (str): | |
| The name of the adapter for which the delta weight should be computed. | |
| """ | |
| device = self.lora_B[adapter].weight.device | |
| dtype = self.lora_A[adapter].weight.dtype | |
| # In case users wants to merge the adapter weights that are in | |
| # float16 while being on CPU, we need to cast the weights to float32, perform the merge and then cast back to | |
| # float16 because the `@` and matmul operation in general is not supported in torch + cpu + fp16. | |
| cast_to_fp32 = device.type == "cpu" and dtype == torch.float16 | |
| weight_A = self.lora_A[adapter].weight | |
| weight_B = self.lora_B[adapter].weight | |
| if cast_to_fp32: | |
| weight_A = weight_A.float() | |
| weight_B = weight_B.float() | |
| # https://github.com/bmaltais/kohya_ss/blob/feb6728762a8f463d15ba936d189d4c3abfaa1ab/networks/lora.py#L117 | |
| if self.get_base_layer().weight.size()[2:4] == (1, 1): | |
| # conv2d 1x1 | |
| output_tensor = (weight_B.squeeze(3).squeeze(2) @ weight_A.squeeze(3).squeeze(2)).unsqueeze(2).unsqueeze( | |
| 3 | |
| ) * self.scaling[adapter] | |
| else: | |
| # conv2d 3x3 | |
| output_tensor = ( | |
| F.conv2d( | |
| weight_A.permute(1, 0, 2, 3), | |
| weight_B, | |
| ).permute(1, 0, 2, 3) | |
| * self.scaling[adapter] | |
| ) | |
| if cast_to_fp32: | |
| output_tensor = output_tensor.to(dtype=dtype) | |
| # cast back the weights | |
| self.lora_A[adapter].weight.data = weight_A.to(dtype) | |
| self.lora_B[adapter].weight.data = weight_B.to(dtype) | |
| return output_tensor | |
| def _get_weight_norm(self, weight, lora_weight, scaling) -> torch.Tensor: | |
| # calculate L2 norm of weight matrix, channel-wise | |
| weight = weight + scaling * lora_weight | |
| # the following is needed to have compatibility with the 4D weight tensors of Conv2D | |
| weight_norm = weight.norm(p=2, dim=(1, 2, 3), keepdim=True).transpose(1, 0) | |
| return weight_norm | |
| def _apply_dora(self, x, lora_A, lora_B, scaling, active_adapter): | |
| """ | |
| For DoRA, calculate the extra output from LoRA with DoRA applied. This should be added on top of the base layer | |
| output. | |
| """ | |
| base_layer = self.get_base_layer() | |
| weight = base_layer.weight | |
| lora_weight = torch.mm(lora_B.weight.flatten(start_dim=1), lora_A.weight.flatten(start_dim=1)) | |
| lora_weight = lora_weight.reshape(weight.shape) | |
| magnitude = self.lora_magnitude_vector[active_adapter] | |
| weight_norm = self._get_weight_norm(weight, lora_weight, scaling) | |
| # see section 4.3 of DoRA (https://arxiv.org/abs/2402.09353) | |
| # "[...] we suggest treating ||V +∆V ||_c in | |
| # Eq. (5) as a constant, thereby detaching it from the gradient | |
| # graph. This means that while ||V + ∆V ||_c dynamically | |
| # reflects the updates of ∆V , it won’t receive any gradient | |
| # during backpropagation" | |
| weight_norm = weight_norm.detach() | |
| mag_norm_scale = magnitude / weight_norm | |
| result_dora = (mag_norm_scale - 1) * ( | |
| F.conv2d( | |
| x, | |
| weight, | |
| bias=None, | |
| stride=base_layer.stride, | |
| padding=base_layer.padding, | |
| dilation=base_layer.dilation, | |
| groups=base_layer.groups, | |
| ) | |
| ) + mag_norm_scale * lora_B(lora_A(x)) * scaling | |
| return result_dora | |
| def forward(self, x: torch.Tensor, *args, **kwargs) -> torch.Tensor: | |
| self._check_forward_args(x, *args, **kwargs) | |
| adapter_names = kwargs.pop("adapter_names", None) | |
| if self.disable_adapters: | |
| if self.merged: | |
| self.unmerge() | |
| result = self.base_layer(x, *args, **kwargs) | |
| elif adapter_names is not None: | |
| result = self._mixed_batch_forward(x, *args, adapter_names=adapter_names, **kwargs) | |
| elif self.merged: | |
| result = self.base_layer(x, *args, **kwargs) | |
| else: | |
| result = self.base_layer(x, *args, **kwargs) | |
| torch_result_dtype = result.dtype | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| lora_A = self.lora_A[active_adapter] | |
| lora_B = self.lora_B[active_adapter] | |
| dropout = self.lora_dropout[active_adapter] | |
| scaling = self.scaling[active_adapter] | |
| x = x.to(lora_A.weight.dtype) | |
| if not self.use_dora[active_adapter]: | |
| result = result + lora_B(lora_A(dropout(x))) * scaling | |
| else: | |
| x = dropout(x) | |
| result = result + self._apply_dora(x, lora_A, lora_B, scaling, active_adapter) | |
| return result | |
| def __repr__(self) -> str: | |
| rep = super().__repr__() | |
| return "lora." + rep | |
| class InflatedConv3d(nn.Module, LoraLayer): | |
| # Lora implemented in a conv2d layer | |
| def __init__( | |
| self, | |
| base_layer: nn.Module, | |
| adapter_name: str, | |
| r: int = 0, | |
| lora_alpha: int = 1, | |
| lora_dropout: float = 0.0, | |
| init_lora_weights: Union[bool, str] = True, | |
| use_rslora: bool = False, | |
| use_dora: bool = False, | |
| **kwargs, | |
| ) -> None: | |
| super().__init__() | |
| LoraLayer.__init__(self, base_layer) | |
| self._active_adapter = adapter_name | |
| self.update_layer( | |
| adapter_name, | |
| r, | |
| lora_alpha=lora_alpha, | |
| lora_dropout=lora_dropout, | |
| init_lora_weights=init_lora_weights, | |
| use_rslora=use_rslora, | |
| use_dora=use_dora, | |
| ) | |
| def update_layer(self, adapter_name, r, lora_alpha, lora_dropout, init_lora_weights, use_rslora, use_dora): | |
| if r <= 0: | |
| raise ValueError(f"`r` should be a positive integer value but the value passed is {r}") | |
| self.r[adapter_name] = r | |
| self.lora_alpha[adapter_name] = lora_alpha | |
| if lora_dropout > 0.0: | |
| lora_dropout_layer = nn.Dropout(p=lora_dropout) | |
| else: | |
| lora_dropout_layer = nn.Identity() | |
| self.lora_dropout[adapter_name] = lora_dropout_layer | |
| # Actual trainable parameters | |
| base_layer = self.get_base_layer() | |
| kernel_size = base_layer.kernel_size | |
| stride = base_layer.stride | |
| padding = base_layer.padding | |
| self.lora_A[adapter_name] = nn.Conv2d(self.in_features, r, kernel_size, stride, padding, bias=False) | |
| self.lora_B[adapter_name] = nn.Conv2d(r, self.out_features, (1, 1), (1, 1), bias=False) | |
| if use_rslora: | |
| self.scaling[adapter_name] = lora_alpha / math.sqrt(r) | |
| else: | |
| self.scaling[adapter_name] = lora_alpha / r | |
| if init_lora_weights == "loftq": | |
| self.loftq_init(adapter_name) | |
| elif init_lora_weights: | |
| self.reset_lora_parameters(adapter_name, init_lora_weights) | |
| weight = getattr(base_layer, "weight", None) | |
| if weight is not None: | |
| # the layer is already completely initialized, this is an update | |
| self.to(base_layer.weight.device, dtype=weight.dtype) | |
| if use_dora: | |
| self.dora_init(adapter_name) | |
| self.use_dora[adapter_name] = True | |
| else: | |
| self.use_dora[adapter_name] = False | |
| self.set_adapter(self.active_adapters) | |
| def merge(self, safe_merge: bool = False, adapter_names: Optional[list[str]] = None) -> None: | |
| """ | |
| Merge the active adapter weights inside the base weights | |
| Args: | |
| safe_merge (`bool`, *optional*): | |
| If True, the merge operation will be performed in a copy of the original weights and check for NaNs | |
| before merging the weights. This is useful if you want to check if the merge operation will produce | |
| NaNs. Defaults to `False`. | |
| adapter_names (`list[str]`, *optional*): | |
| The list of adapter names that should be merged. If None, all active adapters will be merged. Defaults | |
| to `None`. | |
| """ | |
| adapter_names = check_adapters_to_merge(self, adapter_names) | |
| if not adapter_names: | |
| # no adapter to merge | |
| return | |
| for active_adapter in adapter_names: | |
| if active_adapter in self.lora_A.keys(): | |
| base_layer = self.get_base_layer() | |
| if safe_merge: | |
| # Note that safe_merge will be slower than the normal merge | |
| # because of the copy operation. | |
| orig_weights = base_layer.weight.data.clone() | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| orig_weights = orig_weights + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(orig_weights, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| orig_weights = dora_factor.view(-1, 1, 1, 1) * (orig_weights + delta_weight) | |
| if not torch.isfinite(orig_weights).all(): | |
| raise ValueError( | |
| f"NaNs detected in the merged weights. The adapter {active_adapter} seems to be broken" | |
| ) | |
| base_layer.weight.data = orig_weights | |
| else: | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| base_layer.weight.data = base_layer.weight.data + delta_weight | |
| else: | |
| # handle dora | |
| # since delta_weight already includes scaling, set it to 1 here | |
| weight_norm = self._get_weight_norm(base_layer.weight, delta_weight, scaling=1).detach() | |
| # We need to cache weight_norm because it has to be based on the original weights. We | |
| # cannot calculate it on the fly based on the merged weights when unmerging because its a | |
| # different value | |
| self._cache_store(f"{active_adapter}-weight_norm", weight_norm) | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| new_weight = dora_factor.view(-1, 1, 1, 1) * (base_layer.weight.data + delta_weight) | |
| base_layer.weight.data = new_weight | |
| self.merged_adapters.append(active_adapter) | |
| def unmerge(self) -> None: | |
| """ | |
| This method unmerges all merged adapter layers from the base weights. | |
| """ | |
| if not self.merged: | |
| warnings.warn("Already unmerged. Nothing to do.") | |
| return | |
| while len(self.merged_adapters) > 0: | |
| active_adapter = self.merged_adapters.pop() | |
| if active_adapter in self.lora_A.keys(): | |
| weight = self.get_base_layer().weight | |
| delta_weight = self.get_delta_weight(active_adapter) | |
| if not self.use_dora[active_adapter]: | |
| weight.data -= delta_weight | |
| else: | |
| weight_norm = self._cache_pop(f"{active_adapter}-weight_norm") | |
| dora_factor = self.lora_magnitude_vector[active_adapter] / weight_norm | |
| weight_orig = weight.data / dora_factor.view(-1, 1, 1, 1) - delta_weight | |
| weight.data = weight_orig | |
| def get_delta_weight(self, adapter) -> torch.Tensor: | |
| """ | |
| Compute the delta weight for the given adapter. | |
| Args: | |
| adapter (str): | |
| The name of the adapter for which the delta weight should be computed. | |
| """ | |
| device = self.lora_B[adapter].weight.device | |
| dtype = self.lora_A[adapter].weight.dtype | |
| # In case users wants to merge the adapter weights that are in | |
| # float16 while being on CPU, we need to cast the weights to float32, perform the merge and then cast back to | |
| # float16 because the `@` and matmul operation in general is not supported in torch + cpu + fp16. | |
| cast_to_fp32 = device.type == "cpu" and dtype == torch.float16 | |
| weight_A = self.lora_A[adapter].weight | |
| weight_B = self.lora_B[adapter].weight | |
| if cast_to_fp32: | |
| weight_A = weight_A.float() | |
| weight_B = weight_B.float() | |
| # https://github.com/bmaltais/kohya_ss/blob/feb6728762a8f463d15ba936d189d4c3abfaa1ab/networks/lora.py#L117 | |
| if self.get_base_layer().weight.size()[2:4] == (1, 1): | |
| # conv2d 1x1 | |
| output_tensor = (weight_B.squeeze(3).squeeze(2) @ weight_A.squeeze(3).squeeze(2)).unsqueeze(2).unsqueeze( | |
| 3 | |
| ) * self.scaling[adapter] | |
| else: | |
| # conv2d 3x3 | |
| output_tensor = ( | |
| F.conv2d( | |
| weight_A.permute(1, 0, 2, 3), | |
| weight_B, | |
| ).permute(1, 0, 2, 3) | |
| * self.scaling[adapter] | |
| ) | |
| if cast_to_fp32: | |
| output_tensor = output_tensor.to(dtype=dtype) | |
| # cast back the weights | |
| self.lora_A[adapter].weight.data = weight_A.to(dtype) | |
| self.lora_B[adapter].weight.data = weight_B.to(dtype) | |
| return output_tensor | |
| def _get_weight_norm(self, weight, lora_weight, scaling) -> torch.Tensor: | |
| # calculate L2 norm of weight matrix, channel-wise | |
| weight = weight + scaling * lora_weight | |
| # the following is needed to have compatibility with the 4D weight tensors of Conv2D | |
| weight_norm = weight.norm(p=2, dim=(1, 2, 3), keepdim=True).transpose(1, 0) | |
| return weight_norm | |
| def _apply_dora(self, x, lora_A, lora_B, scaling, active_adapter): | |
| """ | |
| For DoRA, calculate the extra output from LoRA with DoRA applied. This should be added on top of the base layer | |
| output. | |
| """ | |
| base_layer = self.get_base_layer() | |
| weight = base_layer.weight | |
| lora_weight = torch.mm(lora_B.weight.flatten(start_dim=1), lora_A.weight.flatten(start_dim=1)) | |
| lora_weight = lora_weight.reshape(weight.shape) | |
| magnitude = self.lora_magnitude_vector[active_adapter] | |
| weight_norm = self._get_weight_norm(weight, lora_weight, scaling) | |
| # see section 4.3 of DoRA (https://arxiv.org/abs/2402.09353) | |
| # "[...] we suggest treating ||V +∆V ||_c in | |
| # Eq. (5) as a constant, thereby detaching it from the gradient | |
| # graph. This means that while ||V + ∆V ||_c dynamically | |
| # reflects the updates of ∆V , it won’t receive any gradient | |
| # during backpropagation" | |
| weight_norm = weight_norm.detach() | |
| mag_norm_scale = magnitude / weight_norm | |
| result_dora = (mag_norm_scale - 1) * ( | |
| F.conv2d( | |
| x, | |
| weight, | |
| bias=None, | |
| stride=base_layer.stride, | |
| padding=base_layer.padding, | |
| dilation=base_layer.dilation, | |
| groups=base_layer.groups, | |
| ) | |
| ) + mag_norm_scale * lora_B(lora_A(x)) * scaling | |
| return result_dora | |
| def forward(self, x: torch.Tensor, *args, **kwargs) -> torch.Tensor: | |
| self._check_forward_args(x, *args, **kwargs) | |
| adapter_names = kwargs.pop("adapter_names", None) | |
| ori_dim = x.ndim | |
| if ori_dim == 5: | |
| frames = x.shape[2] | |
| x = rearrange(x, "b c f h w -> (b f) c h w") | |
| if self.disable_adapters: | |
| if self.merged: | |
| self.unmerge() | |
| result = self.base_layer(x, *args, **kwargs) | |
| elif adapter_names is not None: | |
| result = self._mixed_batch_forward(x, *args, adapter_names=adapter_names, **kwargs) | |
| elif self.merged: | |
| result = self.base_layer(x, *args, **kwargs) | |
| else: | |
| result = self.base_layer(x, *args, **kwargs) | |
| torch_result_dtype = result.dtype | |
| for active_adapter in self.active_adapters: | |
| if active_adapter not in self.lora_A.keys(): | |
| continue | |
| lora_A = self.lora_A[active_adapter] | |
| lora_B = self.lora_B[active_adapter] | |
| dropout = self.lora_dropout[active_adapter] | |
| scaling = self.scaling[active_adapter] | |
| x = x.to(lora_A.weight.dtype) | |
| if not self.use_dora[active_adapter]: | |
| result = result + lora_B(lora_A(dropout(x))) * scaling | |
| else: | |
| x = dropout(x) | |
| result = result + self._apply_dora(x, lora_A, lora_B, scaling, active_adapter) | |
| result = result.to(torch_result_dtype) | |
| if ori_dim == 5: | |
| result = rearrange(result, "(b f) c h w -> b c f h w", f=frames) | |
| return result | |
| def __repr__(self) -> str: | |
| rep = super().__repr__() | |
| return "lora." + rep | |
| def dispatch_default( | |
| target: torch.nn.Module, | |
| adapter_name: str, | |
| lora_config: LoraConfig, | |
| **kwargs, | |
| ) -> Optional[torch.nn.Module]: | |
| new_module = None | |
| if isinstance(target, BaseTunerLayer): | |
| target_base_layer = target.get_base_layer() | |
| else: | |
| target_base_layer = target | |
| if isinstance(target_base_layer, torch.nn.Embedding): | |
| embedding_kwargs = kwargs.copy() | |
| embedding_kwargs.pop("fan_in_fan_out", None) | |
| embedding_kwargs.update(lora_config.loftq_config) | |
| new_module = Embedding(target, adapter_name, **embedding_kwargs) | |
| elif 'InflatedConv3d' in str(type(target_base_layer)): | |
| kwargs.update(lora_config.loftq_config) | |
| new_module = InflatedConv3d(target, adapter_name, **kwargs) | |
| elif isinstance(target_base_layer, torch.nn.Conv2d): | |
| kwargs.update(lora_config.loftq_config) | |
| new_module = Conv2d(target, adapter_name, **kwargs) | |
| elif isinstance(target_base_layer, torch.nn.Linear): | |
| if kwargs["fan_in_fan_out"]: | |
| warnings.warn( | |
| "fan_in_fan_out is set to True but the target module is `torch.nn.Linear`. " | |
| "Setting fan_in_fan_out to False." | |
| ) | |
| kwargs["fan_in_fan_out"] = lora_config.fan_in_fan_out = False | |
| kwargs.update(lora_config.loftq_config) | |
| new_module = Linear(target, adapter_name, **kwargs) | |
| elif isinstance(target_base_layer, Conv1D): | |
| if not kwargs["fan_in_fan_out"]: | |
| warnings.warn( | |
| "fan_in_fan_out is set to False but the target module is `Conv1D`. " "Setting fan_in_fan_out to True." | |
| ) | |
| kwargs["fan_in_fan_out"] = lora_config.fan_in_fan_out = True | |
| kwargs.update(lora_config.loftq_config) | |
| new_module = Linear(target, adapter_name, is_target_conv_1d_layer=True, **kwargs) | |
| return new_module | |