I released a softmax-free attention model at GPT-2 Medium scale (~354M params, 11.5B tokens): structural sparsity + tile-skipping kernels for long-context VRAM savings. Open weights + custom Triton kernels [R]
Summary
Released RRT-355M, a softmax-free attention model at GPT-2 Medium scale with 354M parameters trained from scratch on 11.5B tokens, using structural sparsity and tile-skipping kernels for long-context efficiency, achieving comparable performance to GPT-2 Medium on a 22-task benchmark.
View Cached Full Text
Cached at: 06/22/26, 01:35 AM
Tripstoph/RRT-Foundation · Hugging Face
Source: https://huggingface.co/Tripstoph/RRT-Foundation
https://huggingface.co/Tripstoph/RRT-Foundation#rrt-355m–softmax-free-attention-at-gpt-2-medium-scaleRRT-355M — softmax-free attention at GPT-2 Medium scale
Headline result:a GPT-2 Medium–shaped checkpoint (~354 Mparameters) trainedfrom scratch without softmax, evaluated on astandardized 22-task in-context learning benchmark, withopen kernelswhere sparse inference isbit-identical to denseon this checkpoint.
This Hugging Face repo shipsweights, config, and substrate constantsonly.Inference requires the RRT engineon GitHub (RRT-LLM-FOUNDATION, AGPL-3.0). StocktransformersGPT-2 will produce incorrect outputs.
Training iscomplete. No additional checkpoints are planned from this repository.
https://huggingface.co/Tripstoph/RRT-Foundation#capability-evaluation-22-task-coreCapability evaluation (22-task CORE)
ModelCORENotesGPT-2 124M0.1211floor reference, same harnessGPT-2 medium0.1770dense softmax foil, matched scaleRRT-355M****0.1558softmax-free, this checkpointPythia 410M0.1895modern baseline, same harness
CORE= mean centered accuracy across 22 in-context learning tasks (DCLM protocol, Karpathy nanochateval\_bundle). RRT-355M is0.021 belowthe GPT-2 medium foil and0.035 abovethe GPT-2 124M floor — a measurable tradeoff, not a capability collapse.
**Task asymmetry (RRT − GPT-2 medium, centered score):**gains on multiple-choice reasoning (arc\_easy+0.12,agi\_eval\_lsat\_ar+0.09,openbook\_qa+0.07); largest regressions on continuation tasks (lambada\_openai−0.16,coqa−0.13,squad−0.07).
**Not evaluated:**MMLU, GSM8K, HumanEval, chat/instruction benchmarks, or fine-tuned downstream tasks. Details:eval/eval\_summary\.jsonon this repo; full write-up onGitHubdocs/EVALUATION\.md.
https://huggingface.co/Tripstoph/RRT-Foundation#mechanism-and-trainingMechanism and training
MetricValueNotesStructural edge sparsity99.66 %fidelity gate; training measurementTraining dataFineWeb-Edu11.534 B tokens, 4× H100, 22k itersBest val loss (ckpt)2.8001iteration 21 000Weight file~1011 MB bf16model\.safetensors
Three metrics — do not conflate:(1) structural sparsity during training, (2) coarse-tile skip at inference (34–55%, long context), (3) CORE behavioral score above.
Each attention edge applies frictionln\(max\(i−j, 1\)\)and gateμ = η / \(1 \+ η^n\)^\(1/n\)withn = 1\.25. INT8 pre-pass skips tiles with no active edges;bit-identicalto dense on this checkpoint. v2 kernel:21/22 CORE tasks identicalto v1 (Δ CORE −0.0016).
https://huggingface.co/Tripstoph/RRT-Foundation#systems-notes-secondarySystems notes (secondary)
MetricValueCaveatINT8 tile skip @ T=2048 / 819234% / 55%layer-12 micro-bench, H100Kernel vs SDPA @ T=204811.5×not end-to-end generationPeak attention VRAM @ T=163845.5 GBGPT-2 XLreference forward, RTX 3070
https://huggingface.co/Tripstoph/RRT-Foundation#files-in-this-repoFiles in this repo
FilePurposemodel\.safetensorsbf16 weightsconfig\.jsonarchitecture metadatarrt\_substrate\_constants\.jsoninference requiresn\_backbone,C\_maxonlyeval/CORE summary JSON, comparison CSV, parity notesfigures/key charts from benchmark reporttokenizer\_pointer\.txt``openai\-community/gpt2BPE
https://huggingface.co/Tripstoph/RRT-Foundation#reproduceReproduce
git clone https://github.com/tripstoph/RRT-LLM-FOUNDATION.git
cd RRT-LLM-FOUNDATION
pip install -e .
python eval/run_core_eval.py --model rrt:_state/ckpt.pt --snapshot-dir engine --seed 1337
# Quick smoke (~minutes): python eval/smoke_core.py --model rrt:_state/ckpt.pt --snapshot-dir engine
Expected full CORE:0.1558. Claims ↔ evidence:GitHubdocs/CLAIMS\.md.
https://huggingface.co/Tripstoph/RRT-Foundation#scopeScope
RRT-355M validates the attention mechanism in isolation. Broader pipeline work is explored separately underRelational Autopoietic Substrate (RAS); no timeline or additional model releases are committed from this repository.
https://huggingface.co/Tripstoph/RRT-Foundation#limitationsLimitations
- Custom Triton engine (Hopper sm_90); not
AutoModelForCausalLM - CORE below dense GPT-2 medium at matched scale
- Single checkpoint; no scale-up from this repo
- Speed/memory figures are kernel benchmarks with stated context
https://huggingface.co/Tripstoph/RRT-Foundation#citationCitation
@misc{rrt-355m-2026,
author = {Tripstoph},
title = {RRT-355M: Softmax-free attention at GPT-2 Medium scale},
year = {2026},
publisher = {HuggingFace},
howpublished = {\url{https://huggingface.co/Tripstoph/RRT-Foundation}},
note = {Proof-of-mechanism weights; engine at GitHub under AGPL-3.0.},
}
Last updated: 2026-06-21
Similar Articles
@tilderesearch: https://x.com/tilderesearch/status/2061771450168889432
Wall Attention generalizes diagonal forget gates to softmax attention, enabling state-of-the-art length extrapolation from 4k to 160k+ context zero-shot and outperforming RoPE and FoX in pretraining. It is released as a drop-in replacement with open-source Triton kernels.
@ModelScope2022: 1M-token context with only ~3B parameters active per token. Meituan’s LongCat-Flash-Lite-Sparse brings sparse attention…
Meituan released LongCat-Flash-Lite-Sparse, a sparse-attention model supporting 1M-token context with only ~3B active parameters per token, achieving strong SWE-Bench scores under an MIT license.
I built a new attention mechanism (wave field) — runs 128K context where standard attention OOMs, 80+ tok/s on laptop CPU
A solo researcher introduces Wave Field attention, replacing standard O(N²) dot-product attention with FFT wave convolution, achieving O(N log N) training and O(1) inference per token. Claimed 80+ tok/s on CPU with 128K context and better zero-shot performance than GPT-2 124M.
MiniMax Sparse Attention
MiniMax Sparse Attention introduces a blockwise sparse attention mechanism that achieves significant speedups for ultra-long-context LLMs, reducing per-token attention compute by 28.4x at 1M context with wall-clock speedups of 14.2x for prefill and 7.6x for decoding on H800 GPUs. The method is accompanied by an open-source inference kernel and a publicly released multimodal model.
Built and released BetterGPT-150M – A compact 150M parameter completion model (+ live HF Space demo)
Built and released BetterGPT-150M, a compact 150M parameter causal language model that outperforms GPT-2 Small with low resource footprint. Includes live Hugging Face Space demo for text completion.

