⚠️ Use batch_size=1. Some attention branches (NSA family) do not consume a padding mask, so batching padded sequences can silently corrupt results. Run inference one sequence at a time (batch_size=1).

Aether-7B-5Attn — Base

Aether family5Attn IT 7Attn Base 11Attn Checkpoints Demo Blog Collection

Aether-7B-5Attn

Blog

📚 Part of the Aether Foundation Model collection — base, instruction-tuned, and checkpoints in one place.

🧩 Intermediate checkpoints (110k · 115k · 162k) are released as a dataset: Aether-7B-5Attn-checkpoints.

🇰🇷 The first Korean foundation model to open its training data and training code

A 6.59B MoE language model that arranges its attention across 49 layers on a 7×7 Latin square. Weights · training data recipe · training code · complete training logs · full architecture source — all released.

Trained from scratch on 16 × NVIDIA B200 (2-node FSDP) over ~46 days, 144.2B tokens total. Apache-2.0


1. Why release everything

Most "open" LLMs today give you weights only. Weights alone let you neither understand a model, nor verify it, nor rebuild it. A model whose diet is secret is a black box, and you cannot build national or institutional AI sovereignty on a black box.

The Allen Institute's OLMo reset the bar for what "open" means — that only by releasing the training data, the training code, and the logs alongside the weights does a model become science. Aether follows that bar.

What we release

Item Aether
1 Weights (annealed base)
2 Full architecture source — 5 attention types, MoE, Latin-square placement aether_pkg/
3 Training data recipe — source repos, configs, token counts, mixing weights, tokenizer, EOS ✅ §5
4 Tokenization script — the exact file we ran tokenize_one.py
5 Training code — FSDP launcher, training loop, node scripts launcher_v2b_multi.py et al.
6 Every training hyperparameter ✅ §6
7 Complete training log — all 162,000 steps, 30 days logs/
8 Evaluation code eval/lmeval_run.py
9 Intermediate checkpoints (110k · 115k · 162k)
10 License Apache-2.0

The recipe in §5 alone is enough to reconstruct our training data byte-for-byte. Every source is a public repository, so identical tokenizer + EOS + mixing weights produce identical binaries. Please verify it. That is what it is for.

A first for Korean foundation models

Korea has built foundation models from scratch before. None of them released their training data. To our knowledge, Aether is the first.

This is what sovereign AI actually means. Any country, any company, any lab should be able to rebuild its own foundation model from scratch using nothing but this repository. Downloading someone else's weights is not sovereignty.


Open-source fully-open LLMs — 6-country comparison

Open-source LLM comparison

Across six sovereign fully-open LLMs, disclosure is comparable; Aether is the only single AI startup, with the most attention types (5) in a Latin-square layout.

2. Design — why should every layer use the same attention?

2.1 Nothing says one attention must serve all layers

Since GPT, nearly every transformer uses the same attention at every layer. A 49-layer model runs the same operation 49 times.

But layers do different jobs. Early layers pick up local morphology and grammar; middle layers handle syntactic structure; late layers work across the whole document. If the job is different, why must the operation be identical?

This is a question about a design assumption, not about performance. "Every layer, same attention" is not a proven conclusion — it is a convention that was never seriously questioned. Aether relaxes it.

2.2 Each attention carries a different inductive bias

Type What it is good at What it costs
full Sees every token pair exactly. No information lost Quadratic in length
sliding Sees locality very cheaply (linear in length) Blind beyond the window
differential Subtracts two attention maps to cancel common-mode noise Splits the head dimension in half
nsa Gates compressed, selected and sliding branches to reach far cheaply Structurally complex
hybrid Combines nsa's reach with differential's noise suppression The most expensive

None of them dominates the others. Each is good at something different and pays a different price. Which means picking one and repeating it 49 times also repeats its weakness 49 times.

2.3 The Latin square is a control, not decoration

"Mixing should help" is an easy intuition, but mixing carelessly makes the result impossible to attribute. If full happens to cluster in the late layers, the model did well "because its late layers are full" — not "because it is heterogeneous."

That is why the 49 layers form a 7 × 7 Latin square. A Latin square is a combinatorial arrangement that guarantees each type appears exactly once in each position, structurally preventing any type from concentrating at any depth.

The Latin square is therefore a control mechanism: it lets the question "what does heterogeneous placement do?" be asked without placement bias.

To our knowledge, no released model places heterogeneous attention in a Latin square.


3. Attention composition — a 7×7 Latin square over 49 layers

Seven attention labels are placed across 49 layers along the Latin square, exactly 7 layers each (7 × 7 = 49).

Label Layers Description
full 7 Standard causal attention (SDPA)
differential 7 Splits Q·K in half, builds two attention maps, subtracts them λ-weighted to cancel common noise
sliding 7 Sliding window (window = 512) — masking over the full path
nsa 7 Compressed / selected / sliding branches combined by a learned gate
hybrid 7 nsa + differential combined
compress 7 NSA block-mean path — runs the full path in this checkpoint
linear 7 SDPA + a learned gate
Total 49

Where the name 5Attn comes from. The seven labels reduce to five distinct mechanisms: compress runs the full path, and linear is SDPA plus a gate. The model is named for the number of mechanisms (5), not the number of labels (7).

The placement rule and every implementation are in aether_pkg/. See LATIN_SQUARE_7x7 for the layer↔label mapping.

3.1 Measured cost profile per mechanism

Each of the five mechanisms was measured as a single standalone layer: prefill latency and peak memory. An attention's compute and memory cost is a property of the architecture, independent of trained weight values, so this table is reproducible by anyone.

Type 2K (ms / GB) 8K (ms / GB) 32K (ms / GB)
full 0.4 / 0.0 1.5 / 0.2 13.6 / 0.7
differential 0.5 / 0.1 3.7 / 0.3 46.5 / 1.1
sliding 0.6 / 0.1 1.9 / 0.2 7.6 / 0.8
nsa 1.0 / 0.1 3.6 / 0.3 26.8 / 3.5
hybrid 1.5 / 0.1 7.7 / 0.3 74.7 / 3.5

The "different prices" of §2.2 show up as numbers.

  • At 32K, sliding (7.6 ms) is 1.8× faster than full (13.6 ms) — exactly as a locality-only design should behave. The gap widens with context (at 2K, full is actually faster).
  • hybrid runs both nsa and differential, so its cost converges to their sum (26.8 + 46.5 ≈ 74.7).
  • The full model handles a 32K context in 3.46 GB.

To our knowledge, no measured per-type cost profile for heterogeneous attention has been published. The table itself is material for follow-up work.

This table describes cost only. It makes no claim about output quality. Comparing quality requires a controlled experiment in which attention composition is the only variable, and that must be run separately.


3.2 Structure in depth — the 7×7 Latin square

7x7 Latin-Square Attention Placement

The 49 layers form a 7 × 7 Latin square. Each layer's attention type is:

attention_type(layer) = ATTN_TYPES[(row + col) mod 7]
  where row = layer // 7,  col = layer % 7

Latin-square property

  • Each type appears exactly once in every row and exactly once in every column (7 types × 7 layers = 49) — this is the definition of a Latin square.
  • As a result, no attention type concentrates at any depth (early/middle/late). The cyclic shift spreads every type evenly across depth.
  • Why 7: 7 is prime, so the cyclic shift (row+col) mod 7 yields a proper Latin square (each row and column is a permutation of the 7 types), and 7² = 49 layers fits exactly.

Why this placement — a control

"Mixing should help" is easy to assume, but careless mixing makes the result impossible to attribute: if full happens to cluster in late layers, the model did well "because its late layers are full", not "because it is heterogeneous". The Latin square removes that bias structurally, so the question "what does heterogeneous placement do?" can be asked without depth bias. It is a control mechanism for reproducible science, not decoration.

7 labels → 5 mechanisms

Seven labels are placed (nsa, differential, full, linear, sliding, compress, hybrid), but there are five distinct mechanisms: compress runs the full path and linear is SDPA + a gate (hatched in the figure). The name 5Attn follows the number of mechanisms (5), not labels (7).

To our knowledge, no released model places heterogeneous attention in a Latin square.

4. Specifications

Item Value
Total parameters 6.59B
Active parameters ~2.98B (per token)
Layers 49 (7×7 Latin square)
Experts 25, top-7 routing, 1 shared expert
Expert intermediate 640
hidden / intermediate 2048 / 6144
heads / KV heads / head_dim 16 / 4 / 128
Vocabulary 151,936 (Qwen-compatible tokenizer)
Training context 4096
dtype bfloat16
Size 13.2 GB
Class AETHERV27wayForCausalLM (trust_remote_code=True)

5. Training data — the complete recipe

The information below alone is enough to reconstruct our training data byte-for-byte.

5.1 Sources

File Repository Config Tokens License
eng_fineweb_edu.bin HuggingFaceFW/fineweb-edu sample-100BT 15.000B ODC-By
syn_cosmopedia.bin HuggingFaceTB/smollm-corpus cosmopedia-v2 8.000B ODC-By
math_finemath.bin HuggingFaceTB/finemath finemath-3plus 6.002B ODC-By
code_opc.bin OpenCoder-LLM/opc-fineweb-code-corpus default 5.001B MIT
math_owm.bin open-web-math/open-web-math default 4.004B see source repo
kor_webtext.bin HAERAE-HUB/KOREAN-WEBTEXT default 2.492B see source repo
kor_synth.bin HAERAE-HUB/KOREAN-SyntheticText-1.5B default 1.650B see source repo
phase15_mix_90b.bin Earlier blend of the sources above 90B

Preprocessing: AutoTokenizer.from_pretrained("Qwen/Qwen3-14B"), EOS 151645 inserted at document boundaries, written as a flat uint32 array. The reproduction script tokenize_one.py is included.

python tokenize_one.py HuggingFaceFW/fineweb-edu sample-100BT text 15 out/eng_fineweb_edu.bin

5.2 Mixing weights

DATA_POOL = [                          # (file, sampling weight)
    ("phase15_mix_90b.bin",   1.0),
    ("eng_fineweb_edu.bin",   2.0),
    ("syn_cosmopedia.bin",    2.0),
    ("math_finemath.bin",     3.5),
    ("math_owm.bin",          3.5),
    ("code_opc.bin",          2.5),
    ("kor_webtext.bin",       2.0),
    ("kor_synth.bin",         2.0),
]

Effective share (weights sum to 18.5):

Domain Share
Math (finemath + open-web-math) 37.8%
Korean (webtext + synth) 21.6%
English web & synthetic (fineweb-edu + cosmopedia) 21.6%
Code (opc) 13.5%
phase15 blend 5.4%

6. Training

Item Value
Hardware NVIDIA B200 × 16 (2-node FSDP)
Total training window 2026-05-30 → 2026-07-16, ~46 days
Final stage 2026-06-15 → 07-16, 30 days 11 hours, 16 × B200, ~11,700 B200-hours
Throughput (final stage) ~32,000 tok/s
Total steps 162,000
Total tokens 144.2B
Optimizer AdamW, β=(0.9, 0.95), eps=1e-8
LR cosine, peak 5e-5 → min 5e-6
Weight decay 0.1 (transformer layers) / 0.0 (embeddings, norms)
Embedding LR multiplier 0.1
Layer-wise decay 0.97
Grad clip 1.0
Sequence 4096
Post annealing (this checkpoint is the annealed one)

The training code (launcher_v2b_multi.py, launcher_v2b_multi.py, run_s1.sh, run_s2.sh) and the complete training log are included.


7. Evaluation

lm-evaluation-harness 0.4.11, 0-shot, n=600, batch_size=1.

7.1 English

Task acc acc_norm
SciQ 73.7 63.0
PIQA 66.3 65.8
BoolQ 54.3
ARC-Easy 52.5 48.7
WinoGrande 51.8
HellaSwag 37.2 41.0
OpenBookQA 20.0 32.6
ARC-Challenge 22.2 25.8

7.2 Korean (KoBEST)

Task Score
HellaSwag (acc_norm) 44.6 ±2.2
COPA 57.2 ±2.0
SentiNeg 55.7 ±2.5
WiC 48.8 ±2.0
BoolQ 47.8 ±2.0

7.3 Language modeling

Input Perplexity
A natural Korean sentence 5.4
The same sentence, word order scrambled 41.3
Random tokens 2233.4

Korean grammatical and semantic structure was learned normally.


8. Usage

import torch
from transformers import AutoTokenizer, AutoModelForCausalLM

MODEL = "FINAL-Bench/Aether-7B-5Attn"
tok = AutoTokenizer.from_pretrained(MODEL)
model = AutoModelForCausalLM.from_pretrained(
    MODEL, trust_remote_code=True, torch_dtype=torch.bfloat16, device_map="cuda"
)

ids = tok("인공지능이란", return_tensors="pt").to("cuda")
out = model.generate(**ids, max_new_tokens=128,
                     do_sample=True, temperature=0.8, top_p=0.9,
                     repetition_penalty=1.1)
print(tok.decode(out[0], skip_special_tokens=True))

Notes for use

  • This is a base model. It is not instruction-tuned. An instruct version is in preparation.
  • Use do_sample=True. As is typical for base models, greedy decoding falls into repetition.
  • Use batch_size=1 or unpadded inputs. Because of the custom attention implementations, outputs may differ under left-padded batching.
  • Serve with HF transformers. vLLM is not yet supported — this is a custom architecture.
  • No safety alignment. This is a research base model with no RLHF or safety tuning. Do not deploy it as-is.

9. Release scope

Item Status
Weights (annealed base) ✅ this repo
Full architecture source aether_pkg/
Training data recipe (sources, configs, token counts, mixing weights, tokenizer, EOS) ✅ §5
Tokenization script tokenize_one.py
Training code launcher_v2b_multi.py, launcher_v2b_multi.py, run_s1.sh, run_s2.sh
All training hyperparameters ✅ §6
Complete training log logs/
Evaluation code eval/lmeval_run.py
Intermediate checkpoints ✅ step 110k / 115k / 162k
Paper in preparation

License: Apache-2.0 (weights and code). Training data follows the license of each source repository (§5.1).


10. Citation

@misc{aether7b5attn2026,
  title  = {Aether-7B-5Attn: A Heterogeneous-Attention Mixture-of-Experts Language Model},
  author = {VIDRAFT},
  year   = {2026},
  url    = {https://huggingface.co/FINAL-Bench/Aether-7B-5Attn}
}

11. Contact

VIDRAFT Inc. · arxivgpt@gmail.com

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