## How packing works
Consider four tokenized documents:
[1]
[2]
[10, 11, 12, 13, 14, 15, 16, 17]
[20]
With:
```
StreamingDataset(
table,
shuffle=False,
columns=["tokens"],
num_splits=2,
pack_sequences=5,
eos_id=9,
pad_id=0,
blocks_per_epoch=6,
)
```
the documents are assigned to two fixed logical splits. Each split
maintains an independent token buffer, appends eos_id after every
document, and emits blocks of five tokens.
Because blocks_per_epoch=6, each split emits exactly three blocks:
Cycl/e 1:
Split 0: [1, 9, 2, 9, 0] # 9 is eos, 0 is padding
Split 1: [10, 11, 12, 13, 14]
Cycle 2:
Split 0: [0, 0, 0, 0, 0]
Split 1: [15, 16, 17, 9, 20]
Cycle 3:
Split 0: [0, 0, 0, 0, 0]
Split 1: [9, 0, 0, 0, 0]
If a split runs out of tokens early, it emits padded blocks through the
fixed budget. This prevents one rank from finishing before another.
Logical splits are independent of rank and worker ownership. A
checkpoint records each split’s consumed-document count, emitted-block
count, remaining tokens, and document boundaries. Merging
those per-split states allows the same packed stream to resume after the
topology changes.
doc_ids identifies document segments, including continuations across
block boundaries. It is not a padding mask: padding retains the
preceding document ID, so callers must mask padding using a
reserved pad_id.
blocks_per_epoch="auto" is also available. It estimates the budget from
a deterministic bounded sample and warns that the result is approximate.
WIP pre-training tests:
```
┌────────────────────────────────────┬────────────────────────┬─────────────────────────────────────┐
│ │ GPT-2 124M │ GPT-2 medium 354M │
├────────────────────────────────────┼────────────────────────┼─────────────────────────────────────┤
│ Corpus │ 2.4M docs / 12GB table │ 9.67M docs / 45GB table │
│ Tokens (Chinchilla) │ 2.43B │ 7.0B │
├────────────────────────────────────┼────────────────────────┼─────────────────────────────────────┤
│ Data prep (ingest→curate→tokenize) │ ~12 min │ ~51 min │
├────────────────────────────────────┼────────────────────────┼─────────────────────────────────────┤
│ Training wall time │ ~50 min │ 3h 06m │
├────────────────────────────────────┼────────────────────────┼─────────────────────────────────────┤
│ Throughput / MFU │ 1.60M tok/s / 35% │ 684k tok/s / 42.0%, │
├────────────────────────────────────┼────────────────────────┼─────────────────────────────────────┤
│ Final val loss │ 3.230 │ 2.840 │
└────────────────────────────────────┴────────────────────────┴─────────────────────────────────────┘
```
---------
Co-authored-by: OpenAI Codex <codex@openai.com>
The Multimodal AI Lakehouse
How to Install ✦ Detailed Documentation ✦ Tutorials and Recipes ✦ Contributors
The ultimate multimodal data platform for AI/ML applications.
LanceDB is designed for fast, scalable, and production-ready vector search. It is built on top of the Lance columnar format. You can store, index, and search over petabytes of multimodal data and vectors with ease. LanceDB is a central location where developers can build, train and analyze their AI workloads.
Demo: Multimodal Search by Keyword, Vector or with SQL
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Key Features:
- Fast Vector Search: Search billions of vectors in milliseconds with state-of-the-art indexing.
- Comprehensive Search: Support for vector similarity search, full-text search and SQL.
- Multimodal Support: Store, query and filter vectors, metadata and multimodal data (text, images, videos, point clouds, and more).
- Advanced Features: Zero-copy, automatic versioning, manage versions of your data without needing extra infrastructure. GPU support in building vector index.
Products:
- Open Source & Local: 100% open source, runs locally or in your cloud. No vendor lock-in.
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Ecosystem:
- Columnar Storage: Built on the Lance columnar format for efficient storage and analytics.
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- Rich Ecosystem: Integrations with LangChain 🦜️🔗, LlamaIndex 🦙, Apache-Arrow, Pandas, Polars, DuckDB and more on the way.
How to Install:
Follow the Quickstart doc to set up LanceDB locally.
API & SDK: We also support Python, Typescript and Rust SDKs
| Interface | Documentation |
|---|---|
| Python SDK | https://lancedb.github.io/lancedb/python/python/ |
| Typescript SDK | https://lancedb.github.io/lancedb/js/globals/ |
| Rust SDK | https://docs.rs/lancedb/latest/lancedb/index.html |
| REST API | https://docs.lancedb.com/api-reference/rest |
Join Us and Contribute
We welcome contributions from everyone! Whether you're a developer, researcher, or just someone who wants to help out.
If you have any suggestions or feature requests, please feel free to open an issue on GitHub or discuss it on our Discord server.
Check out the GitHub Issues if you would like to work on the features that are planned for the future. If you have any suggestions or feature requests, please feel free to open an issue on GitHub.
