Skip to main content
Pre-release

This release is a pre-release and may not be stable for production use.

Haliax

Build Status Documentation Status License PyPI

Though you don’t seem to be much for listening, it’s best to be careful. If you managed to catch hold of even just a piece of my name, you’d have all manner of power over me.
— Patrick Rothfuss, The Name of the Wind

Haliax is a JAX library for building neural networks with named tensors, in the tradition of Alexander Rush's Tensor Considered Harmful. Named tensors improve the legibility and compositionality of tensor programs by using named axes instead of positional indices as typically used in NumPy, PyTorch, etc.

Despite the focus on legibility, Haliax is also fast, typically about as fast as "pure" JAX code. Haliax is also built to be scalable: it can support Fully-Sharded Data Parallelism (FSDP) and Tensor Parallelism with just a few lines of code. Haliax powers Levanter, our companion library for training large language models and other foundation models, with scale proven up to 70B parameters and up to TPU v4-2048.

Example: Attention

Here's a minimal attention module implementation in Haliax. For a more detailed introduction, please see the Haliax tutorial. (We use the excellent Equinox library for its module system and tree transformations.)

import equinox as eqx
import jax
import jax.numpy as jnp
import haliax as hax
import haliax.nn as hnn

Pos = hax.Axis("position", 1024)  # sequence length
KPos = Pos.alias("key_position")
Head = hax.Axis("head", 8)  # number of attention heads
Key = hax.Axis("key", 64)  # key size
Embed = hax.Axis("embed", 512)  # embedding size

# alternatively:
#Pos, KPos, Head, Key, Embed = hax.make_axes(pos=1024, key_pos=1024, head=8, key=64, embed=512)


def attention_scores(Key, KPos, query, key, mask):
    # how similar is each query to each key
    scores = hax.dot(query, key, axis=Key) / jnp.sqrt(Key.size)

    if mask is not None:
        scores -= 1E9 * (1.0 - mask)

    # convert to probabilities
    scores = haliax.nn.softmax(scores, KPos)
    return scores


def attention(Key, KPos, query, key, value, mask):
    scores = attention_scores(Key, KPos, query, key, mask)
    answers = hax.dot(scores, value, axis=KPos)

    return answers


# Causal Mask means that if pos >= key_pos, then pos can attend to key_pos
causal_mask = hax.arange(Pos).broadcast_axis(KPos) >= hax.arange(KPos)


class Attention(eqx.Module):
    proj_q: hnn.Linear  # [Embed] -> [Head, Key]
    proj_k: hnn.Linear  # [Embed] -> [Head, Key]
    proj_v: hnn.Linear  # [Embed] -> [Head, Key]
    proj_answer: hnn.Linear  # output projection from [Head, Key] -> [Embed]

    @staticmethod
    def init(Embed, Head, Key, *, key):
        k_q, k_k, k_v, k_ans = jax.random.split(key, 4)
        proj_q = hnn.Linear.init(In=Embed, Out=(Head, Key), key=k_q)
        proj_k = hnn.Linear.init(In=Embed, Out=(Head, Key), key=k_k)
        proj_v = hnn.Linear.init(In=Embed, Out=(Head, Key), key=k_v)
        proj_answer = hnn.Linear.init(In=(Head, Key), Out=Embed, key=k_ans)
        return Attention(proj_q, proj_k, proj_v, proj_answer)

    def __call__(self, x, mask=None):
        q = self.proj_q(x)
        # Rename "position" to "key_position" for self attention
        k = self.proj_k(x).rename({"position": "key_position"})
        v = self.proj_v(x).rename({"position": "key_position"})

        answers = attention(Key, KPos, q, k, v, causal_mask)

        x = self.proj_answer(answers)
        return x

Haliax was created by Stanford's Center for Research on Foundation Models (CRFM)'s research engineering team. You can find us in the #levanter channel on the unofficial Jax LLM Discord.

Documentation

Tutorials

These are some tutorials to get you started with Haliax. They are available as Colab notebooks:

API Reference

Haliax's API documentation is available at haliax.readthedocs.io.

Contributing

We welcome contributions! Please see CONTRIBUTING.md for more information. We also have a list of good first issues to help you get started. (If those don't appeal, don't hesitate to reach out to us on Discord!)

License

Haliax is licensed under the Apache License, Version 2.0. See LICENSE for the full license text.

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

marin_haliax-0.2.68.dev30690675396.tar.gz (779.4 kB view details)

Uploaded Source

Built Distribution

If you're not sure about the file name format, learn more about wheel file names.

marin_haliax-0.2.68.dev30690675396-py3-none-any.whl (157.7 kB view details)

Uploaded Python 3

File details

Details for the file marin_haliax-0.2.68.dev30690675396.tar.gz.

File metadata

File hashes

Hashes for marin_haliax-0.2.68.dev30690675396.tar.gz
Algorithm Hash digest
SHA256 711534f5e877ece1ae0f698c979e376e802ee3ec407eed9f63c7e4c09eed3a55
MD5 2a9fd28a366cd1d5f456e44241f49045
BLAKE2b-256 3b1558acfc9e846385cdcbd60a9e5be5adcda5ec22936f53121bb0bd73d67fdd

See more details on using hashes here.

Provenance

The following attestation bundles were made for marin_haliax-0.2.68.dev30690675396.tar.gz:

Publisher: marin-release-libs-wheels.yaml on marin-community/marin

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

File details

Details for the file marin_haliax-0.2.68.dev30690675396-py3-none-any.whl.

File metadata

File hashes

Hashes for marin_haliax-0.2.68.dev30690675396-py3-none-any.whl
Algorithm Hash digest
SHA256 c24878d66a3912067e4003456f2e355ed12f6e18f74f88bfe53e7dc450b3bd59
MD5 c63dc751c36c5c81c3d7d6f3aacc09b5
BLAKE2b-256 c4a725f970aa430a38651e71fe8c340958cb46e05b0fb689ba00a7054b81cca7

See more details on using hashes here.

Provenance

The following attestation bundles were made for marin_haliax-0.2.68.dev30690675396-py3-none-any.whl:

Publisher: marin-release-libs-wheels.yaml on marin-community/marin

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Release history Release notifications | RSS feed

This release

Supported by

AWS Cloud computing and Security Sponsor Datadog Monitoring Depot Continuous Integration Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page