File size: 6,054 Bytes
1137e50
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
from __future__ import annotations

import argparse
from pathlib import Path


class OptionalTrainingDependencyError(RuntimeError):
    """Raised when optional LoRA training dependencies are not installed."""


def load_training_dependencies():
    try:
        import torch
        from datasets import load_dataset
        from peft import LoraConfig, get_peft_model
        from transformers import (
            AutoModelForCausalLM,
            AutoTokenizer,
            DataCollatorForLanguageModeling,
            Trainer,
            TrainingArguments,
        )
    except ImportError as exc:
        raise OptionalTrainingDependencyError(
            "Optional training dependencies are unavailable. Install transformers, datasets, peft, and torch."
        ) from exc

    return {
        "torch": torch,
        "load_dataset": load_dataset,
        "LoraConfig": LoraConfig,
        "get_peft_model": get_peft_model,
        "AutoModelForCausalLM": AutoModelForCausalLM,
        "AutoTokenizer": AutoTokenizer,
        "DataCollatorForLanguageModeling": DataCollatorForLanguageModeling,
        "Trainer": Trainer,
        "TrainingArguments": TrainingArguments,
    }


def find_lora_target_modules(model, preferred_targets: list[str]) -> list[str]:
    module_suffixes = {name.split(".")[-1] for name, _ in model.named_modules()}
    return [target for target in preferred_targets if target in module_suffixes]


def train_lora(args: argparse.Namespace) -> None:
    deps = load_training_dependencies()
    torch = deps["torch"]
    load_dataset = deps["load_dataset"]
    LoraConfig = deps["LoraConfig"]
    get_peft_model = deps["get_peft_model"]
    AutoModelForCausalLM = deps["AutoModelForCausalLM"]
    AutoTokenizer = deps["AutoTokenizer"]
    DataCollatorForLanguageModeling = deps["DataCollatorForLanguageModeling"]
    Trainer = deps["Trainer"]
    TrainingArguments = deps["TrainingArguments"]

    tokenizer = AutoTokenizer.from_pretrained(args.model)
    if tokenizer.pad_token is None:
        tokenizer.pad_token = tokenizer.eos_token

    model = AutoModelForCausalLM.from_pretrained(args.model)
    model.config.pad_token_id = tokenizer.pad_token_id

    preferred_targets = ["q_proj", "k_proj", "v_proj", "o_proj", "gate_proj", "up_proj", "down_proj"]
    target_modules = find_lora_target_modules(model, preferred_targets)
    if not target_modules:
        raise ValueError(
            "No common LoRA target modules were found. Expected one of: "
            f"{', '.join(preferred_targets)}. Inspect the model architecture and set compatible targets."
        )

    lora_config = LoraConfig(
        r=args.lora_r,
        lora_alpha=args.lora_alpha,
        lora_dropout=args.lora_dropout,
        bias="none",
        task_type="CAUSAL_LM",
        target_modules=target_modules,
    )
    model = get_peft_model(model, lora_config)
    if hasattr(model, "print_trainable_parameters"):
        model.print_trainable_parameters()

    dataset = load_dataset(
        "json",
        data_files={"train": str(args.train_file), "eval": str(args.eval_file)},
    )

    def tokenize_batch(batch):
        tokenized = tokenizer(
            batch["text"],
            truncation=True,
            max_length=args.max_seq_length,
            padding=False,
        )
        return tokenized

    tokenized_dataset = dataset.map(
        tokenize_batch,
        batched=True,
        remove_columns=dataset["train"].column_names,
    )

    training_args = TrainingArguments(
        output_dir=str(args.output_dir),
        max_steps=args.max_steps,
        per_device_train_batch_size=args.batch_size,
        per_device_eval_batch_size=args.batch_size,
        gradient_accumulation_steps=args.gradient_accumulation_steps,
        learning_rate=args.learning_rate,
        logging_steps=args.logging_steps,
        save_steps=args.max_steps,
        report_to=[],
        remove_unused_columns=False,
    )

    trainer = Trainer(
        model=model,
        args=training_args,
        train_dataset=tokenized_dataset["train"],
        eval_dataset=tokenized_dataset["eval"],
        data_collator=DataCollatorForLanguageModeling(tokenizer=tokenizer, mlm=False),
    )
    trainer.train()

    args.output_dir.mkdir(parents=True, exist_ok=True)
    trainer.model.save_pretrained(args.output_dir)
    tokenizer.save_pretrained(args.output_dir)

    device_name = "cuda" if torch.cuda.is_available() else "cpu"
    print(f"Saved LoRA adapter and tokenizer to {args.output_dir}")
    print(f"Training device detected by torch: {device_name}")


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Fine-tune a RouterCore LoRA adapter.")
    parser.add_argument("--model", required=True, help="Base Hugging Face model name or path.")
    parser.add_argument("--train-file", type=Path, required=True)
    parser.add_argument("--eval-file", type=Path, required=True)
    parser.add_argument("--output-dir", type=Path, required=True)
    parser.add_argument("--max-steps", type=int, default=100)
    parser.add_argument("--batch-size", type=int, default=1)
    parser.add_argument("--gradient-accumulation-steps", type=int, default=8)
    parser.add_argument("--learning-rate", type=float, default=2e-4)
    parser.add_argument("--max-seq-length", type=int, default=1024)
    parser.add_argument("--logging-steps", type=int, default=10)
    parser.add_argument("--lora-r", type=int, default=8)
    parser.add_argument("--lora-alpha", type=int, default=16)
    parser.add_argument("--lora-dropout", type=float, default=0.05)
    return parser.parse_args()


def main() -> None:
    args = parse_args()
    try:
        train_lora(args)
    except OptionalTrainingDependencyError as exc:
        print(str(exc))
        print("Skipping LoRA training. Run `pip install transformers datasets peft torch` to enable it.")
    except ValueError as exc:
        print(f"LoRA training configuration error: {exc}")
        raise SystemExit(2) from exc


if __name__ == "__main__":
    main()