Add LoftQ initialization method for LoRA (huggingface#1150)

---------

Co-authored-by: Sourab Mangrulkar <13534540+pacman100@users.noreply.github.com>
Co-authored-by: Benjamin Bossan <BenjaminBossan@users.noreply.github.com>

README.md

@@ -34,6 +34,7 @@ Supported methods:
 7. MultiTask Prompt Tuning: [Multitask Prompt Tuning Enables Parameter-Efficient Transfer Learning](https://arxiv.org/abs/2303.02861)
 8. LoHa: [FedPara: Low-Rank Hadamard Product for Communication-Efficient Federated Learning](https://arxiv.org/abs/2108.06098)
 9. LoKr: [KronA: Parameter Efficient Tuning with Kronecker Adapter](https://arxiv.org/abs/2212.10650) based on [Navigating Text-To-Image Customization:From LyCORIS Fine-Tuning to Model Evaluation](https://arxiv.org/abs/2309.14859) implementation
+10. LoftQ: [LoftQ: LoRA-Fine-Tuning-aware Quantization for Large Language Models](https://arxiv.org/abs/2310.08659)
 
 ## Getting started
 

examples/loftq_finetuning/README.md

@@ -0,0 +1,69 @@
+# LoftQ: LoRA-fine-tuning-aware Quantization
+
+## Introduction
+
+LoftQ provides better initialization for LoRA adapters A and B, 
+and the Quantization of pre-trained weights W.
+
+## Quantization
+We recommend to save the quantized backbone model as fp16/fp32 
+and load it as [NormalFloat4](https://arxiv.org/abs/2305.14314).
+
+We provide a simple example to show how to quantize llama-2-7b model and save/load it.
+
+```sh
+python quantize_save_load.py \
+    --model_name_or_path meta-llama/Llama-2-7b-hf \
+    --token HF_TOKEN \
+    --bits 4 --iter 5 --rank 16 \
+    --save_dir model_zoo/loftq/
+```
+
+- `HF_TOKEN` is the token used to access to [LLAMA models](https://huggingface.co/meta-llama).
+- `quantize_and_save()` function will quantize the backbone and initialize LoRA adapters. 
+It creates 2 folders under `$save_dir`. The quantized backbone is at `Llama-2-7b-hf-4bit-16rank`,
+and the LoRA adapters are at the sub-folder `Llama-2-7b-hf-4bit-16rank/loftq_init`.
+
+## Fine-tuning
+
+Here is an example to load the quantized backbone and LoRA adapters:
+
+```python
+import os
+
+from transformers import AutoModelForCausalLM
+from peft import PeftModel
+
+
+base_model = AutoModelForCausalLM.from_pretrained(
+    os.path.join(args.save_dir, "Llama-2-7b-hf-4bit-16rank"), 
+    load_in_4bit=True,
+)
+peft_model = PeftModel.from_pretrained(
+    base_model,
+    os.path.join(args.save_dir, "Llama-2-7b-hf-4bit-16rank", "loftq_init"),
+    is_trainable=True,
+)
+```
+
+We also provide an example to fine-tune LoftQ on GSM8K. 
+We load the quantized backbone and LoRA adapters from the [LoftQ Huggingface hub](https://huggingface.co/LoftQ).
+
+```sh
+python train_gsm8k_llama.py \
+    --model_name_or_path LoftQ/Llama-2-7b-hf-4bit-64rank \
+    --output_dir exp_results/gsm8k/llama-2-7b/bit4-rank64/lr3e-4 \
+    --learning_rate 3e-4  \
+    --seed 202 \
+    --dataset_name gsm8k \
+    --dataset_config main \
+    --pad_to_max_length \
+    --max_source_length 128 \
+    --max_target_length 256 \
+    --num_train_epochs 5 \
+    --per_device_train_batch_size 4 \
+    --per_device_eval_batch_size 4 \
+    --gradient_accumulation_steps 4 \
+    --with_tracking \
+    --report_to tensorboard
+```

examples/loftq_finetuning/quantize_save_load.py

@@ -0,0 +1,244 @@
+# coding=utf-8
+# 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.
+
+import argparse
+import os
+
+import torch
+import torch.nn as nn
+from transformers import (
+    AutoModelForCausalLM,
+    AutoModelForSeq2SeqLM,
+    AutoModelForSequenceClassification,
+    AutoTokenizer,
+    BitsAndBytesConfig,
+)
+
+from peft import LoftQConfig, LoraConfig, PeftModel, TaskType, get_peft_model
+
+
+class Shell(nn.Module):
+    def __init__(self, weight, bias=None):
+        super().__init__()
+        self.weight = nn.Parameter(weight, requires_grad=False)
+        if bias is not None:
+            self.bias = nn.Parameter(bias, requires_grad=False)
+
+
+def unwarap_model(model, sub_module_name=".base_layer"):
+    sub_module_name_list = [k.split(sub_module_name)[0] for k in model.state_dict().keys() if sub_module_name in k]
+    sub_module_name_set = set(sub_module_name_list)
+    for name in sub_module_name_set:
+        # get the parent of the submodule
+        name_parent = ".".join(name.split(".")[:-1])
+        name_child = name.split(".")[-1]
+        sub_module = model.get_submodule(name_parent)
+        print(sub_module)
+
+        # replace with shell
+        child = getattr(sub_module, name_child)
+        weight = getattr(child.base_layer, "weight", None)
+        bias = getattr(child.base_layer, "bias", None)
+        shell = Shell(weight, bias)
+
+        setattr(sub_module, name_child, shell)
+
+    print("You have unwrapped the model. Use it on your own risk.")
+
+
+def print_model(model, name):
+    print("=" * 10 + name + "=" * 10)
+    print(model)
+    for name, param in model.named_parameters():
+        if torch.is_tensor(param):
+            if param.dtype in [torch.float32, torch.float16]:
+                print(
+                    name,
+                    param.shape,
+                    param.device,
+                    param.dtype,
+                    param.requires_grad,
+                    param.mean().item(),
+                    param.max().item(),
+                )
+            else:
+                print(name, param.shape, param.device, param.dtype, param.requires_grad)
+
+
+def arg_parse():
+    parser = argparse.ArgumentParser(description="Quantize a model with LoftQ.")
+    parser.add_argument(
+        "--model_name_or_path",
+        type=str,
+        default=None,
+        required=True,
+        help="The name or path of the fp32/16 model.",
+    )
+    parser.add_argument(
+        "--token",
+        type=str,
+        default=None,
+        help="The access token to download model from HuggingFace Hub.",
+    )
+    parser.add_argument(
+        "--bits",
+        type=int,
+        default=4,
+        help="The quantized bits",
+    )
+    parser.add_argument(
+        "--iter",
+        type=int,
+        default=1,
+        help="The alternating steps in LoftQ",
+    )
+    parser.add_argument(
+        "--rank",
+        type=int,
+        default=16,
+        help="The rank of the LoRA adapter",
+    )
+    parser.add_argument(
+        "--save_dir",
+        type=str,
+        default="./model_zoo/loftq/",
+        help="The rank of the LoRA adapter",
+    )
+    args = parser.parse_args()
+    return args
+
+
+def quantize_and_save():
+    args = arg_parse()
+
+    # Download weights and configure LoRA
+    tokenizer = AutoTokenizer.from_pretrained(args.model_name_or_path, token=args.token, trust_remote_code=True)
+    if any(name in args.model_name_or_path.lower() for name in ["llama", "mistral", "falcon"]):
+        model = AutoModelForCausalLM.from_pretrained(
+            args.model_name_or_path, token=args.token, trust_remote_code=True, device_map="auto"
+        )
+        task_type = TaskType.CAUSAL_LM
+        target_modules = ["q_proj", "k_proj", "v_proj", "o_proj", "up_proj", "down_proj", "gate_proj"]
+
+    elif any(name in args.model_name_or_path.lower() for name in ["bart", "t5"]):
+        model = AutoModelForSeq2SeqLM.from_pretrained(args.model_name_or_path, token=args.token, device_map="auto")
+        task_type = TaskType.SEQ_2_SEQ_LM
+        target_modules = ["q_proj", "k_proj", "v_proj", "fc1", "fc2", "out_proj"]
+
+    elif any(name in args.model_name_or_path.lower() for name in ["deberta", "roberta", "bert"]):
+        model = AutoModelForSequenceClassification.from_pretrained(args.model_name_or_path, token=args.token)
+        model = model.cuda()
+        task_type = TaskType.SEQ_CLS
+        target_modules = ["query_proj", "key_proj", "value_proj", "dense"]  # embeddings not supported by peft
+    else:
+        raise NotImplementedError("Other models not supported yet.")
+
+    # Config of LoftQ
+    loftq_config = LoftQConfig(loftq_bits=args.bits, loftq_iter=args.iter)
+
+    lora_config = LoraConfig(
+        task_type=task_type,
+        inference_mode=True,
+        r=args.rank,
+        lora_alpha=16 if task_type is TaskType.CAUSAL_LM else args.rank,
+        lora_dropout=0.1,
+        target_modules=target_modules,
+        init_lora_weights="loftq",
+        loftq_config=loftq_config,
+    )
+
+    # Obtain LoftQ model
+    lora_model = get_peft_model(model, lora_config)
+    base_model = lora_model.get_base_model()
+
+    # Save LoftQ model
+    model_name = args.model_name_or_path.split("/")[-1] + f"-{args.bits}bit" + f"-{args.rank}rank"
+    base_model_dir = os.path.join(args.save_dir, model_name)
+    lora_model_dir = os.path.join(args.save_dir, model_name, "loft_init")
+
+    # save lora adapters first
+    lora_model.base_model.peft_config[
+        "default"
+    ].base_model_name_or_path = base_model_dir  # This can be a local path or Hub model id
+    lora_model.base_model.peft_config["default"].init_lora_weights = True  # Don't apply LoftQ when loading again
+
+    lora_model.save_pretrained(lora_model_dir)
+    print_model(lora_model, "lora_model")
+
+    # remove lora adapters and save the backbone
+    unwarap_model(base_model)
+    base_model.save_pretrained(base_model_dir)
+    tokenizer.save_pretrained(base_model_dir)
+
+    print_model(base_model, "base_model")
+
+    return base_model_dir, lora_model_dir
+
+
+def load_loftq(base_model_path, lora_adapter_path):
+    if any(name in base_model_path.lower() for name in ["llama", "mistral", "falcon"]):
+        model = AutoModelForCausalLM.from_pretrained(
+            base_model_path,
+            device_map="auto",
+            low_cpu_mem_usage=True,
+            quantization_config=BitsAndBytesConfig(
+                load_in_4bit=True,
+                bnb_4bit_use_double_quant=False,
+                bnb_4bit_quant_type="nf4",
+            ),
+        )
+    elif any(name in base_model_path.lower() for name in ["bart", "t5"]):
+        model = AutoModelForSeq2SeqLM.from_pretrained(
+            base_model_path,
+            device_map="auto",
+            low_cpu_mem_usage=True,
+            load_in_4bit=True,
+            quantization_config=BitsAndBytesConfig(
+                load_in_4bit=True,
+                bnb_4bit_use_double_quant=False,
+                bnb_4bit_quant_type="nf4",
+            ),
+        )
+    elif any(name in base_model_path.lower() for name in ["deberta", "roberta", "bert"]):
+        model = AutoModelForSequenceClassification.from_pretrained(
+            base_model_path,
+            low_cpu_mem_usage=True,
+            load_in_4bit=True,
+            quantization_config=BitsAndBytesConfig(
+                load_in_4bit=True,
+                bnb_4bit_use_double_quant=False,
+                bnb_4bit_quant_type="nf4",
+            ),
+        )
+    else:
+        raise NotImplementedError("Other models not supported yet.")
+
+    lora_model = PeftModel.from_pretrained(model, lora_adapter_path, is_trainable=True)
+
+    # Do training or inference below
+    print_model(lora_model, "lora_model")
+    print_model(model, "base_model")
+
+
+if __name__ == "__main__":
+    base_dir, lora_dir = quantize_and_save()
+    load_loftq(base_dir, lora_dir)
+
+# example command:
+# python quantize_save_load.py \
+# --model_name_or_path meta-llama/Llama-2-7b-hf \
+# --token XXX \
+# --bits 4 --iter 5 --rank 16 \
+# --save_dir ./model_zoo/loftq/