H-Transformer-1D

Implementation of H-Transformer-1D, Transformer using hierarchical Attention for sequence learning with subquadratic costs. The encoder (non-autoregressive) flavor of this architecture currently holds the throne for Long Range Arena, a benchmark for efficient transformers.

131k tokens

Install

$ pip install h-transformer-1d

Usage

import torch
from h_transformer_1d import HTransformer1D

model = HTransformer1D(
    num_tokens = 256,          # number of tokens
    dim = 512,                 # dimension
    depth = 12,                # depth
    causal = False,            # autoregressive or not
    max_seq_len = 8192,        # maximum sequence length
    heads = 8,                 # heads
    dim_head = 64,             # dimension per head
    block_size = 128,          # block size
    reversible = True,         # use reversibility, to save on memory with increased depth
    shift_tokens = True        # whether to shift half the feature space by one along the sequence dimension, for faster convergence (experimental feature)
)

x = torch.randint(0, 256, (1, 8000))   # variable sequence length
mask = torch.ones((1, 8000)).bool()    # variable mask length

# network will automatically pad to power of 2, do hierarchical attention, etc

logits = model(x, mask = mask) # (1, 8000, 256)

Citations

@misc{zhu2021htransformer1d,
    title   = {H-Transformer-1D: Fast One-Dimensional Hierarchical Attention for Sequences}, 
    author  = {Zhenhai Zhu and Radu Soricut},
    year    = {2021},
    eprint  = {2107.11906},
    archivePrefix = {arXiv},
    primaryClass = {cs.LG}
}

@software{peng_bo_2021_5196578,
    author       = {PENG Bo},
    title        = {BlinkDL/RWKV-LM: 0.01},
    month        = {aug},
    year         = {2021},
    publisher    = {Zenodo},
    version      = {0.01},
    doi          = {10.5281/zenodo.5196578},
    url          = {https://doi.org/10.5281/zenodo.5196578}
}