Fractus CTE-Atom

A fork of the Hugging Face Fractus Continuous Thought Engine. The only change to the brain is the tokenizer: GPT-2 BPE is gone, the Atomizer is the id stream. This is a new model, trained from zero. It is not a resume of the x8 run.

Engine source: thefinalboss/fractus-cte. GitHub: AFKmoney/fractus-cte-atom. Atomizer source: AFKmoney/atom-ai, vendored as fractus/atomizer.py.

No x8 checkpoint is in this repo. Do not load one.

Philosophy

Three properties, and they are the product.

It thinks continuously. A tick advances a residual thought h through the block stack. Attention carry (S, z) and Kuramoto phase stay live across chunks. Output is a next-id distribution on that state. The Atomizer does not change this. It only changes what an id is.

It trains without a finish line. The checkpoint is a seed. This fork starts at token 0 because the head is new. After that, training only moves forward. Infinite means unbounded continuation, not a promise that a run never crashes.

It opens quickly. The parent paid about 128M parameters for a 50257-id head before a block ran. This head is 266 ids (266 × 1280 ≈ 0.34M tied). No merge table. No Hugging Face tokenizer runtime.

GPU, measured 2026-10-09

One RTX 5090, 1B shape, chunked attention, torch.compile, seq 128, B=2:

Trainable parameters: 985,074,354 (Siren copies frozen: 879,235,072)
TF: 423 Atom ids/s, mean step 0.606 s (was 119 ids/s before removing the 128 .item() syncs in the expert counter)
B=4: OOM on the per-token index_select of the expert factors

The GPU does about 200 ms of real work per step. The wall is about 2 s. The card is idle. The next lever is a capacity dispatch that does not copy weights per token. Do not start the 2.4B-id run at 119 ids/s.

Status, 2026-10-09

Fixes in the body, measured:

Per-token MoE routing. The chunk is gated by each position's own θ, not the last position's. Causal leak on position 0 is 0 after the switch. It was 0.028 after 400 steps with the old expand.
Learned phase encode. _encode_from_hidden uses phase_proj (Linear(d_model, 1), weight std c/√d_model, default c=1). The old mean of a LayerNorm'd h was ~0, so every token hit the same experts. At c=1, phase std before the modulo is ~1.1 rad. Alive experts: 4–5/8 and 28–31/128 fresh, settling to 4/8 and 9–10/128 after 100 steps. Not the old collapse (2 alive), not a random hash.
Speech path works. A small body trained on one repeated phrase with reset_thought every step, greedy PREFIX, no ban: prompt abcdef , output Fractus 12345. abcdef Fracef FraceuFra, unique=19/40. Without the reset the model memorizes the carry: 81% accuracy with the training carry, 3% after reset_thought. Generation starts from zero, so it collapsed.
The trainer cuts the corpus into B lanes. Row b always reads lane b, so its carry continues its own text. The old contiguous layout was wrong for B > 1. BOS reset is per row: a BOS in one lane does not wipe the others. start_token_next is the offset inside each lane; resume with the same BATCH.
fast4gpu_atom.py is the 1B trainer. Fresh start, vocab 266, full Kuramoto fix, refuses a 50257 head, refuses ids outside 0–265, refuses START_TOKEN=0 on resume.
Corpus is 1,059,743 Atom ids. Enough to measure throughput. Not enough to speak. Chinchilla target on ~120M active params is ~2.4B ids.
No GPU rate has been measured. The protocol is in docs/CLAUDE.md.

What was done

The parent body is intact and on the Atom path.

FractusTokenizer is the Atomizer. Vocab is 266. gpt2_compatible() returns Atom on purpose, so old call sites cannot silently build a 50257 head.
LazyStructuredSirenLinear is the MoE expert, not a comment. Two modules per expert, on the dense and sparse forwards. After grow_atom, those modules are copied from the stacked factors, so the body that computes is the body that grew.
Fractal linear attention is on the train forward: QKV, level offsets, ELU feature map, causal linear attention, softmax over level_logits, carry (S, z).
Kuramoto routing fix (gate temperature 2.5, omega ×4) runs at the start of scripts/train_atom_from_scratch.py.
The train loop is v4_forward_losses: chunked CE, load-balance, anti-repeat, optional scheduled sampling. --grow-at N adds a layer and rebuilds the optimizer.
Packet features (320-d) enter through atom_feat, zero-init, placed on the boundary id. A run that does not pass features is unchanged.
Embedding init is N(0, 0.02). Step-0 next-token CE measured 5.592, echo fraction 0.0. Target is ln(266) ≈ 5.583.
Speech path: greedy PREFIX does not ban the previous id. A prompt is an open prefix (encode_open): no EOS, no closing boundary on the tail. A closed encode made the model think the text was finished.
A memorized short phrase spoke. Prompt abcdef , output Fractus 12345. abcdef Fracef FraceuFra, unique=19/40. Teacher-forced accuracy on that phrase was 1 with reset_thought every step. This proves the path can emit a continuation it learned. It is not a 1B speech claim.
Starter corpus: data/atom_corpus.i16, 1,059,743 Atom ids, two French files. Not the phase-2 3.44B stream.
scripts/pod_atom_from_scratch.sh refuses to run unless ATOM_POD=1 is set on a machine that already has the GPU. It does not open a pod.
scripts/train_1b_gpu.py refuses a checkpoint whose vocab is not 266.

Atomization

ATOM does not build a vocabulary. The Atomizer cuts a raw UTF-8 byte stream into spans on structural boundaries: whitespace, punctuation, newline, a switch between letters and digits, a max length of 32 bytes, or the end of the stream. Each span is a packet: the bytes, the boundary that closed it, and a 320-d feature vector. Two spans with the same letters can still differ, because the features include a rolling context sketch. The packet is an event, not a permanent vocab row.

Fractus cannot eat a packet. It ticks one integer. So this fork turns each packet into ids the existing head can embed and predict:

The payload is emitted as raw bytes, ids 0–255. No merge. é is the UTF-8 bytes of é, not a French token.
After the payload, one boundary id (259–265) records why the span closed.
A training document is wrapped with BOS (257) and EOS (258). A generation prompt is not. encode_open leaves the tail unflushed and does not write EOS, so the prompt is a prefix of the longer text the model trained on.

Decode throws away every id ≥ 256 and UTF-8-decodes what remains. Round-trip on the bytes is exact. There is no merge table and no GPT-2 file.

The 320-d features are not ids. They enter through atom_feat, a linear map into d_model, zero at init, added on the boundary position. A run that does not pass features is unchanged.

CPU smoke, measured 2026-10-09 on this fork with all fixes in (fast4gpu_atom.py, B=1, seq 32, 106,754 params, SS_RATE=0.5):

Compare TF ids/s, not wall. The B=1 smoke was wall 1,180 / TF 1,878 with ids_ss/ids_tf = 0.60. The B=2 smoke was wall 2,244 / TF 2,298 with SS off. The wall doubled because SS did not run. The real batch effect is TF 1,878 → 2,298, +22%. Keep SS_RATE fixed and record the ratio, or wall numbers are not comparable.

These are CPU numbers on the small body. They are not a 1B rate. The ~1,000/s parent figure is BPE tokens on a 5090, not Atom ids.

The id stream

ids	meaning
0–255	one raw UTF-8 byte
256	PAD
257	BOS
258	EOS
259–265	boundary marker after a span

Boundary ids are 258 + Atomizer._BOUNDARY_CODES[name]: whitespace 259, punctuation 260, newline 261, class_transition 262, max_span 263, eos-flush 264, generated 265.

Closed encode (training documents): [BOS] + (payload bytes + boundary id) × packets + [EOS]. Open encode (generation prompts): [BOS] + committed packets + tail bytes. No EOS. No boundary on the unflushed tail.

Decode drops every id ≥ 256 and UTF-8-decodes the rest. Round-trip on the bytes is exact.

The alphabet is closed. It does not grow. Every UTF-8 string already fits in 0–255. What grows is the body: d_model, depth, experts, oscillators, rank. grow_atom refuses a vocab change.

Body

Not a transformer. Residual thought h, then per block: fractal linear attention, Kuramoto RK4, phase-routed MoE (128 experts, top-2, low-rank Siren). Tied embed and head. Confidence and salience heads. Persistent memory, cognitive modes, and a knowledge-base retriever exist and are constructed together in fractus/atom_session.py.

1B shape: d_model=1280, 16 blocks, 20 heads, 128 experts, top-2, expert_d_ff=2048, siren_rank=64, n_levels=2. Counted without allocating the weights: about 0.99B total, 119.6M active per token. The old 1.05B figure included the 50257 head. Do not quote it for this fork.

Chinchilla on active params: 20 × 119.6M ≈ 2.4B Atom ids, not BPE tokens. An id is a byte or a boundary. 2.4B ids is less text than 2.4B GPT-2 tokens. Top-4 would roughly double the active expert cost and the data target. 2 of 128 is the parent router, not a new choice. The old ~1,000/s figure is BPE tokens on the x8 run. It has not been remeasured in Atom ids.

Train

pip install torch numpy
python scripts/build_atom_corpus.py --src data/raw --out data/atom_corpus
python scripts/train_atom_from_scratch.py --scale smoke --steps 40
python scripts/train_atom_from_scratch.py --scale 1b --corpus data/atom_corpus.i16

scripts/fast4gpu_atom.py is the Atom 1B trainer. Fresh engine, full Kuramoto fix, or a strict resume of a 266-row checkpoint. It reads .i16 and .npy and refuses any id outside 0..265. It does not slice a parent head. scripts/fast4gpu_boost_v4.py is the parent loop and is not Atom-safe. A CPU smoke of the Atom trainer (106,624 params, B=1, seq 32, 20 steps) ran at 1,378 Atom ids/s wall. That is not a 1B rate.

START_TOKEN=0 is legal only on this new model.

What to measure

Teacher-forced CE falling is not speech. The parent run already showed that: CE around 5–8, unique@40 still about 3.3.

Tokenizer lock. decode(encode(text)) == text on French, English, code, accents, newlines. Every train id in 0..265. Boundary histogram must not be 100% max_span.
Init CE, frozen weights. Near ln(266) ≈ 5.58. Echo fraction near 0. A step-0 CE of tens means the logit scale is blown (the old N(0,1) embed did this: echo 1.0, CE ~58).
Teacher-forced CE. An optimisation trace. Not the gate.
Speech gate. Greedy PREFIX, no ban, no temperature, open prefix. Count unique ids over 40 generated steps, and unique bytes after dropping ids ≥ 256. Do not declare speech off a falling CE.
Prefix alignment. encode_open(prompt) must equal the prefix of encode(prompt + continuation) up to the prompt bytes. If it does not, generation is off the manifold the model trained on.
Load balance. last_lb_loss and per-expert hits. Top-2 of 128 with a dead gate is the parent failure mode.

What is not done

No 1B run. No pod was opened.
The starter corpus is 1.06M ids. That is about 0.04% of the 2.4B active-param target. A 1B on it will memorize the two files.
The speech proof is a memorized 25-id phrase, not free language.
unique40_probe now generates. A low unique count is still NO-GO.

Small-model checks already run

check	result
Init CE / echo	5.592 / 0.0
80-step smoke, no reset	CE 5.56 → ~2.6, thought norm stayed live
Carry across two ticks	moved, and did not return to the previous state
Memorized phrase, open prefix, no ban	`abcdef` → `Fractus 12345.`
Grow then Siren vs factors	identical
Pod script without `ATOM_POD=1`	exit 2

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