alpaca-lora/finetune.py
2023-03-16 15:05:17 -07:00

139 lines
4.0 KiB
Python

import os
# os.environ["CUDA_VISIBLE_DEVICES"] = "0"
import torch
import torch.nn as nn
import bitsandbytes as bnb
from datasets import load_dataset
import transformers
assert (
"LlamaTokenizer" in transformers._import_structure["models.llama"]
), "LLaMA is now in HuggingFace's main branch.\nPlease reinstall it: pip uninstall transformers && pip install git+https://github.com/huggingface/transformers.git"
from transformers import LlamaForCausalLM, LlamaTokenizer
from peft import (
prepare_model_for_int8_training,
LoraConfig,
get_peft_model,
get_peft_model_state_dict,
)
# optimized for RTX 4090. for larger GPUs, increase some of these?
MICRO_BATCH_SIZE = 4 # this could actually be 5 but i like powers of 2
BATCH_SIZE = 128
GRADIENT_ACCUMULATION_STEPS = BATCH_SIZE // MICRO_BATCH_SIZE
EPOCHS = 3 # we don't need 3 tbh
LEARNING_RATE = 3e-4 # the Karpathy constant
CUTOFF_LEN = 256 # 256 accounts for about 96% of the data
LORA_R = 8
LORA_ALPHA = 16
LORA_DROPOUT = 0.05
VAL_SET_SIZE = 2000
model = LlamaForCausalLM.from_pretrained(
"decapoda-research/llama-7b-hf",
load_in_8bit=True,
device_map="auto",
)
tokenizer = LlamaTokenizer.from_pretrained(
"decapoda-research/llama-7b-hf", add_eos_token=True
)
model = prepare_model_for_int8_training(model)
config = LoraConfig(
r=LORA_R,
lora_alpha=LORA_ALPHA,
target_modules=["q_proj", "v_proj"],
lora_dropout=LORA_DROPOUT,
bias="none",
task_type="CAUSAL_LM",
)
model = get_peft_model(model, config)
tokenizer.pad_token_id = 0 # unk. we want this to be different from the eos token
data = load_dataset("json", data_files="alpaca_data.json")
train_val = data["train"].train_test_split(
test_size=VAL_SET_SIZE, shuffle=True, seed=42
)
train_data = train_val["train"]
val_data = train_val["test"]
def generate_prompt(data_point):
# sorry about the formatting disaster gotta move fast
if data_point["input"]:
return f"""Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.
### Instruction:
{data_point["instruction"]}
### Input:
{data_point["input"]}
### Response:
{data_point["output"]}"""
else:
return f"""Below is an instruction that describes a task. Write a response that appropriately completes the request.
### Instruction:
{data_point["instruction"]}
### Response:
{data_point["output"]}"""
def tokenize(prompt):
# there's probably a way to do this with the tokenizer settings
# but again, gotta move fast
result = tokenizer(
prompt,
truncation=True,
max_length=CUTOFF_LEN + 1,
padding="max_length",
)
return {
"input_ids": result["input_ids"][:-1],
"attention_mask": result["attention_mask"][:-1],
}
train_data = train_data.shuffle().map(lambda x: tokenize(generate_prompt(x)))
val_data = val_data.shuffle().map(lambda x: tokenize(generate_prompt(x)))
trainer = transformers.Trainer(
model=model,
train_dataset=train_data,
eval_dataset=val_data,
args=transformers.TrainingArguments(
per_device_train_batch_size=MICRO_BATCH_SIZE,
gradient_accumulation_steps=GRADIENT_ACCUMULATION_STEPS,
warmup_steps=100,
num_train_epochs=EPOCHS,
learning_rate=LEARNING_RATE,
fp16=True,
logging_steps=20,
evaluation_strategy="steps",
save_strategy="steps",
eval_steps=200,
save_steps=200,
output_dir="lora-alpaca",
save_total_limit=3,
load_best_model_at_end=True,
),
data_collator=transformers.DataCollatorForLanguageModeling(tokenizer, mlm=False),
)
model.config.use_cache = False
old_state_dict = model.state_dict
model.state_dict = (
lambda self, *_, **__: get_peft_model_state_dict(self, old_state_dict())
).__get__(model, type(model))
trainer.train()
model.save_pretrained("lora-alpaca")
print("\n If there's a warning about missing keys above, please disregard :)")