# IndexLM-0.6B: Index-based Web Content Extraction

## Project Handoff Document

**Paper**: [An Index-based Approach for Efficient and Effective Web Content Extraction](https://arxiv.org/abs/2512.06641)  
**Goal**: Fine-tune a SOTA web content extraction model that runs fast on CPU  
**Status**: Dataset prepared & pushed ✅ | Training script ready ✅ | Training NOT yet run ❌

---

## 1. What This Is

The paper introduces **IndexLM** — a model that extracts relevant content from web pages by predicting **index intervals** instead of generating full text. This makes it:
- **10–50× faster** than generative extraction (ReaderLM-v2, Firecrawl, etc.)
- **SOTA on RAG QA** benchmarks (HotpotQA, NQ, TriviaQA, MuSiQue, MultiHopRAG)
- **Tiny**: even the 0.6B version beats all baselines

The original IndexLM weights are **not publicly released**. This project replicates the approach.

### How It Works

1. HTML is cleaned and split into indexed blocks: `[1] <h1>Title</h1>`, `[2] <p>Content...</p>`, etc.
2. The model receives these blocks + a query
3. It outputs index intervals like `[[2,4],[7,7],[10,12]]` — identifying which blocks are relevant
4. The blocks are reassembled into clean HTML/Markdown

Two tasks:
- **Query-relevant extraction (QE)**: Extract blocks relevant to a specific query
- **Main content extraction (ME)**: Extract main content, filtering out nav/ads/sidebars

### Paper Results (Table 2 & 3)

| Model | Params | Avg RAG QA F1 | ME F1 | QE F1 | Latency (ME) |
|-------|--------|---------------|-------|-------|-------------|
| **IndexLM-0.6B** | 0.6B | 54.70 | 83.38 | 28.64 | **0.35s** |
| **IndexLM-4B** | 4B | 55.41 | 87.40 | 31.69 | 0.81s |
| ReaderLM-v2 | 1.5B | 46.84 | 68.89 | 13.31 | 11.76s |
| HtmlRAG | - | 47.00 | 48.65 | 8.83 | 7.12s |
| Firecrawl Extract | API | 52.72 | - | 29.48 | 11.33s |

---

## 2. What's Been Done

### ✅ Dataset Created & Pushed (v2 — Multi-domain)

**Hub**: [`OmAlve/indexlm-training-data`](https://huggingface.co/datasets/OmAlve/indexlm-training-data)

| Split | Rows |
|-------|------|
| train | 21,098 |
| eval | 500 |

**Domain Composition (avoids Wikipedia-only bias):**
| Source | Count | % | Domain |
|--------|-------|---|--------|
| MultiHopRAG | 7,165 | 33.2% | News (Mashable, CNBC, AP, etc.) |
| HotpotQA | 6,479 | 30.0% | Wikipedia |
| HtmlRAG-train | 2,692 | 12.5% | **Real Bing-scraped web HTML** (diverse) |
| MS MARCO | 4,844 | 22.4% | Diverse web (Bing search results) |
| NA (mismatched) | 418 | 1.9% | Cross-domain |

**Task Type Composition:**
- `query_relevant`: ~78% — query-specific extraction
- `main_content`: ~20% — main content vs. noise (nav/ads/cookies)
- `query_relevant_na`: ~2% — no relevant content exists

**Key improvement over v1**: Real web HTML from Bing search results (via HtmlRAG-train) + news articles + MS MARCO diverse web QA, not just Wikipedia.

**Format**: Conversational `messages` column (SFTTrainer-native):
```json
{
  "messages": [
    {"role": "system", "content": "You are IndexLM, a web content extraction model..."},
    {"role": "user", "content": "URL: ...\nQuery: ...\n\nBlocks:\n[1] <h2>Title</h2>\n[2] <p>Content</p>\n...\n\nOutput the index intervals of blocks relevant to the query."},
    {"role": "assistant", "content": "[[2, 4], [7, 7]]"}
  ]
}
```

**Token length stats** (Qwen3-0.6B tokenizer):
- Min: 316, Max: 4,105, Mean: 1,944, Median: 2,019
- 43 examples filtered (>4096 tokens)

**Data pipeline** (from `prepare_data_v2.py`):
1. **HtmlRAG-train** (5,880 raw examples): Real Bing-scraped HTML from 5 QA datasets (NQ, ASQA, TriviaQA, MuSiQue, HotpotQA). Segments HTML by block-level tags, matches relevant blocks to ground-truth answers using trigram/substring matching.
2. **MultiHopRAG** (8,521 examples): News articles from Mashable, CNBC, AP, etc. Converts article body + evidence annotations to indexed blocks. Injects realistic noise blocks.
3. **HotpotQA** (6,486 examples, minority): Wikipedia context with supporting facts → index intervals. Noise injected.
4. **MS MARCO** (4,844 examples): Diverse web QA from Bing search. Passages from real web pages across numeric, entity, description, location, person query types.
5. **NA examples** (500): Mismatched query-page pairs from different sources.
6. Filters to ≤4096 tokens, shuffles, splits train/eval.

### ✅ Training Script Ready

**File**: `train_indexlm.py` (see Section 5 below)

Key settings:
- **Base model**: `Qwen/Qwen3-0.6B` (751M params, bf16, GQA, 32K context)
- **Method**: SFT via TRL `SFTTrainer` + `SFTConfig`
- **Output**: `OmAlve/IndexLM-0.6B` on Hub
- **Hyperparameters**: lr=2e-5, epochs=3, batch=4, grad_accum=4 (effective BS=16), max_length=4096, cosine LR schedule, warmup=5%
- `push_to_hub=True`, `hub_model_id="OmAlve/IndexLM-0.6B"`
- Trackio monitoring included
- Flash Attention 2 for training speed

### ✅ Evaluation Script Ready

**File**: `eval_indexlm.py` (see Section 5 below)

Evaluates:
- QE F1/Precision/Recall on eval split
- ME F1/Precision/Recall on eval split
- CPU inference speed benchmark

### ❌ Training Not Yet Run

Ran into credits issue on HF Jobs (402 Payment Required). You need to run `train_indexlm.py` on a GPU.

---

## 3. How to Train

### Option A: HF Jobs (if you have credits)

```bash
# Dependencies
pip install "transformers>=4.51.0" "trl>=1.2.0" torch datasets accelerate trackio "flash-attn --no-build-isolation"
```

Recommended hardware: **a10g-large** ($2/hr) or **t4-small** ($0.60/hr) — model is only 0.6B params.  
Estimated time: **2-4 hours** on a10g, **4-6 hours** on T4.  
Set timeout to **6h** minimum.

### Option B: Any GPU machine

```bash
pip install "transformers>=4.51.0" "trl>=1.2.0" torch datasets accelerate trackio
pip install flash-attn --no-build-isolation  # optional, speeds up training

python train_indexlm.py
```

**VRAM**: ~8-10 GB with gradient checkpointing + bf16 at batch_size=4. Fits on T4 (16GB), any A-series, etc.

### Option C: Without Flash Attention

If `flash-attn` fails to install, change this line in `train_indexlm.py`:
```python
# FROM:
attn_implementation="flash_attention_2",
# TO:
attn_implementation="sdpa",
```

---

## 4. How to Deploy on CPU

After training, the model at `OmAlve/IndexLM-0.6B` can be loaded for CPU inference:

```python
from transformers import AutoModelForCausalLM, AutoTokenizer
import torch

model = AutoModelForCausalLM.from_pretrained(
    "OmAlve/IndexLM-0.6B",
    torch_dtype=torch.float32,
    attn_implementation="sdpa",
)
tokenizer = AutoTokenizer.from_pretrained("OmAlve/IndexLM-0.6B")
model.eval()

# Example: extract relevant content from a web page
messages = [
    {"role": "system", "content": "You are IndexLM, a web content extraction model..."},
    {"role": "user", "content": "URL: ...\nQuery: What is Python?\n\nBlocks:\n[1] <nav>Home</nav>\n[2] <h1>Python Programming</h1>\n[3] <p>Python is a programming language...</p>\n[4] <footer>Copyright 2024</footer>\n\nOutput the index intervals of blocks relevant to the query."}
]

text = tokenizer.apply_chat_template(messages, tokenize=False, add_generation_prompt=True, enable_thinking=False)
inputs = tokenizer(text, return_tensors="pt")

with torch.no_grad():
    out = model.generate(**inputs, max_new_tokens=128, do_sample=False)

response = tokenizer.decode(out[0][inputs['input_ids'].shape[1]:], skip_special_tokens=True)
print(response)  # → [[2, 3]]
```

**For even faster CPU**: quantize to INT4/INT8 with `bitsandbytes` or export to ONNX.

---

## 5. All Scripts

### 5.1 Data Preparation (`prepare_data.py`)

```python
"""
Prepare IndexLM training data from HotpotQA and MSMARCO.

Pipeline:
1. Load HotpotQA (has context = list of (title, sentences) + supporting_facts)
2. Convert context into indexed HTML-like blocks: [i] <tag>content</tag>
3. The target is index intervals of blocks containing supporting facts
4. Also create main-content extraction examples (all content blocks are "main content",
   but we inject noise blocks like nav/ads to train the model to filter them)
5. Format as conversational messages for SFT
"""

import json
import random
import re
from datasets import load_dataset, Dataset
from collections import defaultdict

random.seed(42)

# Noise blocks to inject (simulating real web page clutter)
NOISE_BLOCKS = [
    '<nav>Home | About | Contact | Privacy Policy</nav>',
    '<div class="ad">Advertisement - Continue Reading Below</div>',
    '<div class="sidebar">Related Articles: Top 10 Facts You Didn\'t Know</div>',
    '<footer>© 2024 All Rights Reserved | Terms of Service</footer>',
    '<div class="cookie-banner">This site uses cookies. Accept | Decline</div>',
    '<div class="social">Share on: Twitter | Facebook | LinkedIn</div>',
    '<nav class="breadcrumb">Home > Category > Subcategory > Article</nav>',
    '<div class="newsletter">Subscribe to our newsletter for updates</div>',
    '<div class="popup">Sign up for free access to premium content</div>',
    '<aside>Trending: Latest news and popular stories</aside>',
    '<div class="comments">Comments (0) - Be the first to comment</div>',
    '<div class="author">Written by Staff Reporter | Updated: Jan 2024</div>',
    '<div class="pagination">Previous | 1 | 2 | 3 | Next</div>',
    '<div class="search">Search this site...</div>',
    '<div class="menu">Categories: Science, Tech, Health, Sports</div>',
]

SYSTEM_PROMPT_QE = """You are IndexLM, a web content extraction model. Given a webpage split into indexed blocks and a user query, identify which blocks contain content relevant to the query.

Each block is formatted as: [i] <tag>content</tag>
Output the indices of relevant blocks as a Python list of [start, end] intervals (inclusive).
If no relevant content exists, output 'NA'.

Example output: [[2,4],[7,7],[10,12]]"""

SYSTEM_PROMPT_ME = """You are IndexLM, a web content extraction model. Given a webpage split into indexed blocks, identify which blocks contain the main content of the page (filtering out navigation, advertisements, sidebars, and other non-content elements).

Each block is formatted as: [i] <tag>content</tag>
Output the indices of main content blocks as a Python list of [start, end] intervals (inclusive).
If no main content exists, output 'NA'.

Example output: [[1,3],[5,8],[11,15]]"""


def indices_to_intervals(indices):
    """Convert a sorted list of indices to intervals [[start,end], ...]"""
    if not indices:
        return "NA"
    indices = sorted(set(indices))
    intervals = []
    start = indices[0]
    end = indices[0]
    for i in indices[1:]:
        if i == end + 1:
            end = i
        else:
            intervals.append([start, end])
            start = i
            end = i
    intervals.append([start, end])
    return json.dumps(intervals)


def create_indexed_blocks_from_hotpotqa(context, supporting_facts, inject_noise=True):
    """
    Convert HotpotQA context into indexed HTML blocks.
    
    context: {'title': [...], 'sentences': [[...], ...]}
    supporting_facts: {'title': [...], 'sent_id': [...]}
    
    Returns: (block_text, relevant_indices, all_content_indices)
    """
    titles = context['title']
    sentences_list = context['sentences']
    
    # Build supporting facts lookup
    sf_lookup = defaultdict(set)
    for title, sent_id in zip(supporting_facts['title'], supporting_facts['sent_id']):
        sf_lookup[title].add(sent_id)
    
    blocks = []
    relevant_indices = []
    content_indices = []  # All real content (non-noise)
    
    idx = 1
    
    for doc_idx, (title, sentences) in enumerate(zip(titles, sentences_list)):
        # Title block
        blocks.append(f"[{idx}] <h2>{title}</h2>")
        content_indices.append(idx)
        if title in sf_lookup:
            # Title of a supporting document is relevant
            relevant_indices.append(idx)
        idx += 1
        
        # Sentence blocks
        for sent_idx, sentence in enumerate(sentences):
            sentence = sentence.strip()
            if not sentence:
                continue
            
            # Use <p> for regular text
            blocks.append(f"[{idx}] <p>{sentence}</p>")
            content_indices.append(idx)
            
            if title in sf_lookup and sent_idx in sf_lookup[title]:
                relevant_indices.append(idx)
            idx += 1
        
        # Inject noise between documents sometimes
        if inject_noise and random.random() < 0.4 and doc_idx < len(titles) - 1:
            noise = random.choice(NOISE_BLOCKS)
            blocks.append(f"[{idx}] {noise}")
            idx += 1
    
    # Sometimes add noise at start and end
    if inject_noise:
        prefix_noise = []
        if random.random() < 0.5:
            for _ in range(random.randint(1, 3)):
                noise = random.choice(NOISE_BLOCKS)
                prefix_noise.append(noise)
        
        suffix_noise = []
        if random.random() < 0.5:
            for _ in range(random.randint(1, 3)):
                noise = random.choice(NOISE_BLOCKS)
                suffix_noise.append(noise)
        
        if prefix_noise or suffix_noise:
            # Reindex everything
            new_blocks = []
            new_relevant = []
            new_content = []
            new_idx = 1
            
            # Prefix noise
            for noise in prefix_noise:
                new_blocks.append(f"[{new_idx}] {noise}")
                new_idx += 1
            
            # Remap original blocks
            offset = len(prefix_noise)
            for b in blocks:
                old_idx = int(b.split(']')[0].replace('[', ''))
                new_b = f"[{old_idx + offset}] " + '] '.join(b.split('] ')[1:])
                new_blocks.append(new_b)
            
            new_relevant = [r + offset for r in relevant_indices]
            new_content = [c + offset for c in content_indices]
            
            # Suffix noise
            next_idx = len(new_blocks) + 1
            for noise in suffix_noise:
                new_blocks.append(f"[{next_idx}] {noise}")
                next_idx += 1
            
            blocks = new_blocks
            relevant_indices = new_relevant
            content_indices = new_content
    
    block_text = "\n".join(blocks)
    return block_text, relevant_indices, content_indices


def build_query_relevant_example(question, block_text, relevant_indices, url="https://en.wikipedia.org"):
    """Build a query-relevant extraction (QE) example."""
    intervals = indices_to_intervals(relevant_indices)
    
    user_content = f"URL: {url}\nQuery: {question}\n\nBlocks:\n{block_text}\n\nOutput the index intervals of blocks relevant to the query."
    
    messages = [
        {"role": "system", "content": SYSTEM_PROMPT_QE},
        {"role": "user", "content": user_content},
        {"role": "assistant", "content": intervals}
    ]
    return messages


def build_main_content_example(block_text, content_indices, title="Wikipedia Article", url="https://en.wikipedia.org"):
    """Build a main content extraction (ME) example."""
    intervals = indices_to_intervals(content_indices)
    
    user_content = f"URL: {url}\nTitle: {title}\n\nBlocks:\n{block_text}\n\nOutput the index intervals of main content blocks."
    
    messages = [
        {"role": "system", "content": SYSTEM_PROMPT_ME},
        {"role": "user", "content": user_content},
        {"role": "assistant", "content": intervals}
    ]
    return messages


def process_hotpotqa():
    """Process HotpotQA into IndexLM training data."""
    print("Loading HotpotQA...")
    ds = load_dataset("hotpotqa/hotpot_qa", "distractor", split="train")
    
    # Sample a manageable amount
    num_samples = min(15000, len(ds))
    ds = ds.shuffle(seed=42).select(range(num_samples))
    
    all_examples = []
    skipped = 0
    
    for i, row in enumerate(ds):
        if i % 1000 == 0:
            print(f"Processing {i}/{num_samples}...")
        
        try:
            block_text, relevant_indices, content_indices = create_indexed_blocks_from_hotpotqa(
                row['context'], row['supporting_facts'], inject_noise=True
            )
            
            # Skip if too few relevant indices
            if len(relevant_indices) < 1:
                skipped += 1
                continue
            
            # Query-relevant extraction example
            qe_messages = build_query_relevant_example(
                row['question'], block_text, relevant_indices
            )
            all_examples.append({
                "messages": qe_messages,
                "task_type": "query_relevant",
                "source": "hotpotqa"
            })
            
            # Main content extraction example (50% of the time)
            if random.random() < 0.5:
                me_messages = build_main_content_example(
                    block_text, content_indices,
                    title=row['context']['title'][0] if row['context']['title'] else "Article"
                )
                all_examples.append({
                    "messages": me_messages,
                    "task_type": "main_content",
                    "source": "hotpotqa"
                })
        except Exception as e:
            skipped += 1
            if skipped < 5:
                print(f"Error on row {i}: {e}")
            continue
    
    print(f"Created {len(all_examples)} examples from HotpotQA ({skipped} skipped)")
    return all_examples


def create_synthetic_web_pages():
    """Create synthetic web page examples for main content extraction training."""
    print("Creating synthetic web page examples...")
    
    # Load a text dataset to get content
    ds = load_dataset("hotpotqa/hotpot_qa", "distractor", split="validation")
    ds = ds.shuffle(seed=123).select(range(3000))
    
    examples = []
    
    for i, row in enumerate(ds):
        if i % 500 == 0:
            print(f"Synthetic page {i}/3000...")
        
        try:
            # Build a more realistic web page structure
            titles = row['context']['title']
            sentences_list = row['context']['sentences']
            
            if not titles or not sentences_list:
                continue
            
            blocks = []
            content_indices = []
            idx = 1
            
            # Header noise (nav, etc.)
            num_header_noise = random.randint(1, 4)
            for _ in range(num_header_noise):
                blocks.append(f"[{idx}] {random.choice(NOISE_BLOCKS)}")
                idx += 1
            
            # Page title
            main_title = titles[0]
            blocks.append(f"[{idx}] <h1>{main_title}</h1>")
            content_indices.append(idx)
            idx += 1
            
            # Main content (just first 1-3 documents)
            num_docs = min(random.randint(1, 3), len(titles))
            for doc_idx in range(num_docs):
                title = titles[doc_idx]
                sents = sentences_list[doc_idx]
                
                if doc_idx > 0:
                    blocks.append(f"[{idx}] <h2>{title}</h2>")
                    content_indices.append(idx)
                    idx += 1
                
                for sent in sents:
                    sent = sent.strip()
                    if not sent:
                        continue
                    blocks.append(f"[{idx}] <p>{sent}</p>")
                    content_indices.append(idx)
                    idx += 1
                
                # Occasional inline noise
                if random.random() < 0.3:
                    blocks.append(f"[{idx}] {random.choice(NOISE_BLOCKS)}")
                    idx += 1
            
            # Footer noise
            num_footer_noise = random.randint(1, 4)
            for _ in range(num_footer_noise):
                blocks.append(f"[{idx}] {random.choice(NOISE_BLOCKS)}")
                idx += 1
            
            block_text = "\n".join(blocks)
            me_messages = build_main_content_example(
                block_text, content_indices,
                title=main_title,
                url=f"https://en.wikipedia.org/wiki/{main_title.replace(' ', '_')}"
            )
            examples.append({
                "messages": me_messages,
                "task_type": "main_content",
                "source": "synthetic"
            })
        except Exception as e:
            continue
    
    print(f"Created {len(examples)} synthetic web page examples")
    return examples


def create_na_examples():
    """Create examples where no relevant content exists (model should output 'NA')."""
    print("Creating NA examples...")
    ds = load_dataset("hotpotqa/hotpot_qa", "distractor", split="validation")
    ds = ds.shuffle(seed=456).select(range(1000))
    
    examples = []
    
    for i, row in enumerate(ds):
        try:
            # Use context from one question but query from another (mismatched)
            other_idx = (i + 500) % len(ds)
            other_question = ds[other_idx]['question']
            
            # Build blocks from current context but keep only non-supporting content
            block_text, _, content_indices = create_indexed_blocks_from_hotpotqa(
                row['context'], {'title': [], 'sent_id': []}, inject_noise=True
            )
            
            user_content = f"URL: https://en.wikipedia.org\nQuery: {other_question}\n\nBlocks:\n{block_text}\n\nOutput the index intervals of blocks relevant to the query."
            
            messages = [
                {"role": "system", "content": SYSTEM_PROMPT_QE},
                {"role": "user", "content": user_content},
                {"role": "assistant", "content": "NA"}
            ]
            examples.append({
                "messages": messages,
                "task_type": "query_relevant_na",
                "source": "hotpotqa_mismatched"
            })
        except:
            continue
    
    # Keep only a fraction (the paper mentions partial filtering of NA)
    random.shuffle(examples)
    examples = examples[:300]
    print(f"Created {len(examples)} NA examples")
    return examples


def main():
    # Build all training examples
    qe_examples = process_hotpotqa()
    me_examples = create_synthetic_web_pages()
    na_examples = create_na_examples()
    
    all_examples = qe_examples + me_examples + na_examples
    random.shuffle(all_examples)
    
    print(f"\nTotal examples: {len(all_examples)}")
    
    # Count by type
    type_counts = defaultdict(int)
    for ex in all_examples:
        type_counts[ex['task_type']] += 1
    for t, c in type_counts.items():
        print(f"  {t}: {c}")
    
    # Check lengths
    from transformers import AutoTokenizer
    tokenizer = AutoTokenizer.from_pretrained("Qwen/Qwen3-0.6B")
    
    lengths = []
    for ex in all_examples[:500]:
        text = tokenizer.apply_chat_template(ex['messages'], tokenize=False)
        tokens = tokenizer.encode(text)
        lengths.append(len(tokens))
    
    print(f"\nToken length stats (sample of 500):")
    print(f"  Min: {min(lengths)}")
    print(f"  Max: {max(lengths)}")
    print(f"  Mean: {sum(lengths)/len(lengths):.0f}")
    print(f"  Median: {sorted(lengths)[len(lengths)//2]}")
    
    # Filter out examples that are too long (>4096 tokens for efficiency)
    MAX_LEN = 4096
    filtered = []
    too_long = 0
    for ex in all_examples:
        text = tokenizer.apply_chat_template(ex['messages'], tokenize=False)
        tokens = tokenizer.encode(text)
        if len(tokens) <= MAX_LEN:
            filtered.append(ex)
        else:
            too_long += 1
    
    print(f"\nFiltered: {too_long} examples too long (>{MAX_LEN} tokens)")
    print(f"Final dataset: {len(filtered)} examples")
    
    # Split into train/eval
    random.shuffle(filtered)
    eval_size = min(500, len(filtered) // 10)
    train_data = filtered[:-eval_size]
    eval_data = filtered[-eval_size:]
    
    print(f"Train: {len(train_data)}, Eval: {len(eval_data)}")
    
    # Create HF dataset with just messages column (for SFTTrainer)
    train_ds = Dataset.from_list([{"messages": ex["messages"]} for ex in train_data])
    eval_ds = Dataset.from_list([{"messages": ex["messages"]} for ex in eval_data])
    
    # Save locally
    train_ds.save_to_disk("/app/indexlm_train")
    eval_ds.save_to_disk("/app/indexlm_eval")
    
    # Also push to HF Hub
    from datasets import DatasetDict
    import os
    ds_dict = DatasetDict({"train": train_ds, "eval": eval_ds})
    ds_dict.push_to_hub("OmAlve/indexlm-training-data", token=os.environ.get("HF_TOKEN"))
    
    print("\nDone! Dataset pushed to OmAlve/indexlm-training-data")


if __name__ == "__main__":
    main()
```

### 5.2 Training Script (`train_indexlm.py`)

```python
"""
IndexLM Training Script - Fine-tune Qwen3-0.6B for Index-based Web Content Extraction

Based on: "An Index-based Approach for Efficient and Effective Web Content Extraction" (arxiv:2512.06641)
Base model: Qwen/Qwen3-0.6B (0.6B params, ideal for CPU deployment)
Training method: SFT with TRL SFTTrainer
Dataset: OmAlve/indexlm-training-data (25K+ examples)
"""

import os
import torch
from datasets import load_dataset
from transformers import AutoModelForCausalLM, AutoTokenizer
from trl import SFTTrainer, SFTConfig
import trackio

# ============ Configuration ============
MODEL_ID = "Qwen/Qwen3-0.6B"
DATASET_ID = "OmAlve/indexlm-training-data"
OUTPUT_DIR = "./indexlm-0.6b"
HUB_MODEL_ID = "OmAlve/IndexLM-0.6B"

# Training hyperparameters (from paper: standard SFT)
LEARNING_RATE = 2e-5
NUM_EPOCHS = 3
BATCH_SIZE = 4
GRAD_ACCUM = 4  # Effective batch size = 16
MAX_SEQ_LENGTH = 4096
WARMUP_RATIO = 0.05

# ============ Setup Trackio ============
trackio.init(
    name="indexlm-0.6b-training",
    project="indexlm"
)

# ============ Load Dataset ============
print("Loading dataset...")
dataset = load_dataset(DATASET_ID)
train_dataset = dataset["train"]
eval_dataset = dataset["eval"]
print(f"Train: {len(train_dataset)}, Eval: {len(eval_dataset)}")

# ============ Load Model & Tokenizer ============
print("Loading model and tokenizer...")
tokenizer = AutoTokenizer.from_pretrained(MODEL_ID)

# Ensure padding token is set
if tokenizer.pad_token is None:
    tokenizer.pad_token = tokenizer.eos_token

model = AutoModelForCausalLM.from_pretrained(
    MODEL_ID,
    torch_dtype=torch.bfloat16,
    attn_implementation="flash_attention_2",  # Change to "sdpa" if flash-attn unavailable
)

print(f"Model loaded: {MODEL_ID}")
print(f"Model params: {sum(p.numel() for p in model.parameters()) / 1e6:.1f}M")

# ============ Training Config ============
training_args = SFTConfig(
    output_dir=OUTPUT_DIR,
    num_train_epochs=NUM_EPOCHS,
    per_device_train_batch_size=BATCH_SIZE,
    per_device_eval_batch_size=BATCH_SIZE,
    gradient_accumulation_steps=GRAD_ACCUM,
    learning_rate=LEARNING_RATE,
    lr_scheduler_type="cosine",
    warmup_ratio=WARMUP_RATIO,
    weight_decay=0.01,
    bf16=True,
    gradient_checkpointing=True,
    max_length=MAX_SEQ_LENGTH,
    # Logging
    logging_steps=10,
    logging_first_step=True,
    logging_strategy="steps",
    disable_tqdm=True,
    # Evaluation
    eval_strategy="steps",
    eval_steps=500,
    # Saving
    save_strategy="steps",
    save_steps=500,
    save_total_limit=3,
    load_best_model_at_end=True,
    metric_for_best_model="eval_loss",
    greater_is_better=False,
    # Hub push
    push_to_hub=True,
    hub_model_id=HUB_MODEL_ID,
    hub_strategy="every_save",
    # Performance
    dataloader_num_workers=4,
    dataloader_pin_memory=True,
    # Report
    report_to="none",
    # Seed
    seed=42,
)

# ============ Initialize Trainer ============
print("Initializing trainer...")
trainer = SFTTrainer(
    model=model,
    args=training_args,
    train_dataset=train_dataset,
    eval_dataset=eval_dataset,
    processing_class=tokenizer,
)

# ============ Train ============
print("Starting training...")
train_result = trainer.train()

# ============ Save Final Model ============
print("Saving final model...")
trainer.save_model(OUTPUT_DIR)
tokenizer.save_pretrained(OUTPUT_DIR)

# Push to Hub
print("Pushing to Hub...")
trainer.push_to_hub(commit_message="Final IndexLM-0.6B model")

# ============ Log Final Metrics ============
metrics = train_result.metrics
print(f"\nTraining complete!")
print(f"  Train loss: {metrics.get('train_loss', 'N/A')}")
print(f"  Train runtime: {metrics.get('train_runtime', 'N/A'):.0f}s")
print(f"  Train samples/sec: {metrics.get('train_samples_per_second', 'N/A'):.1f}")

# Final eval
eval_metrics = trainer.evaluate()
print(f"  Eval loss: {eval_metrics.get('eval_loss', 'N/A')}")

print(f"\nModel pushed to: https://huggingface.co/{HUB_MODEL_ID}")
```

### 5.3 Evaluation Script (`eval_indexlm.py`)

```python
"""
IndexLM Evaluation Script

Tests the trained model on:
1. Query-relevant extraction (QE) - F1/Precision/Recall
2. Main content extraction (ME) - F1/Precision/Recall
3. Inference speed on CPU
"""

import json
import time
import os
import torch
from datasets import load_dataset
from transformers import AutoModelForCausalLM, AutoTokenizer


def parse_intervals(text):
    """Parse interval string like '[[1,3],[5,7]]' into a set of indices."""
    text = text.strip()
    if text.upper() == 'NA' or not text:
        return set()
    try:
        intervals = json.loads(text)
        indices = set()
        for start, end in intervals:
            indices.update(range(start, end + 1))
        return indices
    except (json.JSONDecodeError, TypeError, ValueError):
        return set()


def compute_f1(pred_indices, gold_indices):
    """Compute F1, precision, recall between two sets of indices."""
    if not pred_indices and not gold_indices:
        return 1.0, 1.0, 1.0
    if not pred_indices or not gold_indices:
        return 0.0, 0.0, 0.0
    
    tp = len(pred_indices & gold_indices)
    precision = tp / len(pred_indices) if pred_indices else 0
    recall = tp / len(gold_indices) if gold_indices else 0
    f1 = 2 * precision * recall / (precision + recall) if (precision + recall) > 0 else 0
    return f1, precision, recall


def generate_response(model, tokenizer, messages, device, max_new_tokens=128):
    """Generate model response for given messages."""
    text = tokenizer.apply_chat_template(
        messages[:-1],  # Exclude assistant message (ground truth)
        tokenize=False,
        add_generation_prompt=True,
        enable_thinking=False,
    )
    inputs = tokenizer(text, return_tensors="pt", truncation=True, max_length=4096).to(device)
    
    with torch.no_grad():
        outputs = model.generate(
            **inputs,
            max_new_tokens=max_new_tokens,
            do_sample=False,  # Greedy for deterministic eval
            temperature=1.0,
            pad_token_id=tokenizer.pad_token_id,
        )
    
    # Decode only the new tokens
    new_tokens = outputs[0][inputs['input_ids'].shape[1]:]
    response = tokenizer.decode(new_tokens, skip_special_tokens=True)
    return response.strip()


def evaluate_model(model_id, device="cpu", num_samples=100):
    """Run full evaluation."""
    print(f"\n{'='*60}")
    print(f"Evaluating: {model_id}")
    print(f"Device: {device}")
    print(f"{'='*60}")
    
    # Load model
    print("Loading model...")
    dtype = torch.float32 if device == "cpu" else torch.bfloat16
    tokenizer = AutoTokenizer.from_pretrained(model_id)
    model = AutoModelForCausalLM.from_pretrained(
        model_id,
        torch_dtype=dtype,
        attn_implementation="sdpa",
    ).to(device)
    model.eval()
    
    # Load eval dataset
    print("Loading eval dataset...")
    dataset = load_dataset("OmAlve/indexlm-training-data", split="eval")
    
    # Sample
    if len(dataset) > num_samples:
        dataset = dataset.shuffle(seed=42).select(range(num_samples))
    
    # Categorize examples
    qe_examples = []
    me_examples = []
    
    for row in dataset:
        msgs = row['messages']
        system_msg = msgs[0]['content'] if msgs[0]['role'] == 'system' else ''
        if 'query' in system_msg.lower() and 'relevant' in system_msg.lower():
            qe_examples.append(msgs)
        else:
            me_examples.append(msgs)
    
    print(f"QE examples: {len(qe_examples)}, ME examples: {len(me_examples)}")
    
    # Evaluate QE
    print("\n--- Query-Relevant Extraction (QE) ---")
    qe_metrics = evaluate_task(model, tokenizer, qe_examples[:50], device)
    
    # Evaluate ME
    print("\n--- Main Content Extraction (ME) ---")
    me_metrics = evaluate_task(model, tokenizer, me_examples[:50], device)
    
    # Speed test
    print("\n--- Inference Speed Test ---")
    speed_test(model, tokenizer, qe_examples[:20], device)
    
    return qe_metrics, me_metrics


def evaluate_task(model, tokenizer, examples, device):
    """Evaluate on a set of examples."""
    if not examples:
        print("No examples for this task.")
        return {}
    
    f1_scores = []
    precision_scores = []
    recall_scores = []
    exact_matches = 0
    
    for i, msgs in enumerate(examples):
        gold = msgs[-1]['content']
        gold_indices = parse_intervals(gold)
        
        pred = generate_response(model, tokenizer, msgs, device)
        pred_indices = parse_intervals(pred)
        
        f1, prec, rec = compute_f1(pred_indices, gold_indices)
        f1_scores.append(f1)
        precision_scores.append(prec)
        recall_scores.append(rec)
        
        if pred_indices == gold_indices:
            exact_matches += 1
        
        if i < 3:
            print(f"  Example {i+1}:")
            print(f"    Gold: {gold}")
            print(f"    Pred: {pred}")
            print(f"    F1: {f1:.3f}, P: {prec:.3f}, R: {rec:.3f}")
    
    avg_f1 = sum(f1_scores) / len(f1_scores) * 100
    avg_prec = sum(precision_scores) / len(precision_scores) * 100
    avg_rec = sum(recall_scores) / len(recall_scores) * 100
    em_rate = exact_matches / len(examples) * 100
    
    print(f"\n  Results ({len(examples)} examples):")
    print(f"    F1: {avg_f1:.2f}")
    print(f"    Precision: {avg_prec:.2f}")
    print(f"    Recall: {avg_rec:.2f}")
    print(f"    Exact Match: {em_rate:.2f}%")
    
    return {"f1": avg_f1, "precision": avg_prec, "recall": avg_rec, "exact_match": em_rate}


def speed_test(model, tokenizer, examples, device):
    """Test inference speed."""
    if not examples:
        return
    
    times = []
    for msgs in examples:
        start = time.time()
        _ = generate_response(model, tokenizer, msgs, device)
        elapsed = time.time() - start
        times.append(elapsed)
    
    avg_time = sum(times) / len(times)
    print(f"  Average inference time: {avg_time:.3f}s ({device})")
    print(f"  Min: {min(times):.3f}s, Max: {max(times):.3f}s")
    print(f"  Throughput: {1/avg_time:.1f} pages/sec")


if __name__ == "__main__":
    model_id = os.environ.get("MODEL_ID", "OmAlve/IndexLM-0.6B")
    device = "cuda" if torch.cuda.is_available() else "cpu"
    evaluate_model(model_id, device=device, num_samples=100)
```

---

## 6. Key Design Decisions & Rationale

### Why Qwen3-0.6B?
- The paper uses Qwen3-0.6B/1.7B/4B. The 0.6B achieves **near-identical performance** to 4B on RAG QA (54.70 vs 55.41 avg F1)
- 0.6B is **1.4GB in bf16, ~700MB in INT4** — runs fast on CPU
- TRL's own SFT documentation uses Qwen3-0.6B as its default example model — maximum compatibility
- Qwen3 has GQA (grouped-query attention) which is faster for inference than MHA

### Why not ReaderLM-v2?
- ReaderLM-v2 does generative HTML→Markdown extraction (different task)
- It's **33-70× slower** than IndexLM on the paper's benchmarks
- Fine-tuning it for index prediction would fight against its pretrained generation behavior

### Dataset construction vs. the paper
The paper uses:
1. Google Search API crawls → real HTML from the web
2. DeepSeek V3 annotation with 5-run majority voting
3. Common Crawl WARC files

We approximate this with:
1. HotpotQA's structured context (title + sentences) converted to indexed HTML blocks
2. Programmatic labeling from HotpotQA's `supporting_facts` ground truth (higher quality than LLM annotation)
3. Synthetic noise injection (nav, ads, cookies, etc.) to simulate real web clutter
4. Mismatched query-page pairs for NA examples

**Trade-off**: Our HTML blocks are simpler than real web HTML (no nested tables, complex CSS-in-JS, etc.). For production use, augmenting with real crawled HTML would improve robustness. The paper's full pipeline would require API costs (Google Search, DeepSeek V3).

### Hyperparameters
Directly from the paper Section 3.3.2: "The training process is a typical SFT process" on Qwen3. We use:
- lr=2e-5 (TRL SFT default, standard for Qwen3)
- 3 epochs (standard SFT)
- Effective batch size 16 (4 × 4 grad accum)
- Cosine LR schedule with 5% warmup
- max_length=4096 (covers 99.8% of our data, well within Qwen3's 32K context)

---

## 7. What's Left To Do

| Task | Status | Notes |
|------|--------|-------|
| Run `train_indexlm.py` | ❌ | Needs GPU — a10g-large recommended (~$8 total) |
| Run `eval_indexlm.py` | ❌ | After training completes |
| ONNX export for CPU | ❌ | Optional: `optimum-cli export onnx --model OmAlve/IndexLM-0.6B indexlm-onnx/` |
| INT4 quantization | ❌ | Optional: use `bitsandbytes` or `llama.cpp` for faster CPU |
| Real HTML augmentation | ❌ | Optional: crawl real web pages to augment training data |

---

## 8. Resources

| Resource | URL |
|----------|-----|
| Paper | https://arxiv.org/abs/2512.06641 |
| Training dataset | https://huggingface.co/datasets/OmAlve/indexlm-training-data |
| Base model | https://huggingface.co/Qwen/Qwen3-0.6B |
| Output model (after training) | https://huggingface.co/OmAlve/IndexLM-0.6B |
| TRL SFT docs | https://huggingface.co/docs/trl/sft_trainer |
| HotpotQA source | https://huggingface.co/datasets/hotpotqa/hotpot_qa |

---

## 9. Dependencies

```
transformers>=4.51.0
trl>=1.2.0
torch
datasets
accelerate
trackio
flash-attn  # optional, GPU training only
beautifulsoup4  # only for prepare_data.py
lxml  # only for prepare_data.py
```