What this setting does
Partition the pool by WebOrganizer topic and give each of the 24 categories a quota equal to its share of pool tokens; rank by fastText percentile within topic. S_DIV = ∪_c Top_{p_c·Bs}(D_c, r_fastText).
The coverage extreme of the quality/diversity trade-off. Topic quotas left this arm with a 4,889,635,504-token rewritten component instead of 5B (a 110,364,496-token shortfall concentrated in Adult, History, Literature and Religion), so its corpus is 9.89B tokens and it trains 14,147 steps rather than 14,305.
Every one of the six settings trains on a 10B-token mixture built the same way: a shared 5B-token
anchor of top-ranked DCLM fastText documents, identical across all six settings and never
rewritten, plus 5B tokens contributed by this setting's selection strategy. Only that second
half differs between settings, so downstream differences isolate source selection alone.
Quick start
The repo root is a copy of seed 42 at the end of epoch 3, so from_pretrained works with no
subfolder argument:
from transformers import AutoModelForCausalLM, AutoTokenizer
model = AutoModelForCausalLM.from_pretrained("blab-jhu/KYS-1.5B-Diversity-Oriented")
tok = AutoTokenizer.from_pretrained("blab-jhu/KYS-1.5B-Diversity-Oriented")
Any other checkpoint is addressed by subfolder:
model = AutoModelForCausalLM.from_pretrained("blab-jhu/KYS-1.5B-Diversity-Oriented", subfolder="seed43/epoch1")
Layout
. <- copy of seed42/epoch3 (seed 42, end of epoch 3)
seed42/epoch1 epoch2 epoch3
seed43/epoch1 epoch2 epoch3
seed44/epoch1 epoch2 epoch3
Each directory is a complete HF checkpoint: config.json, generation_config.json,
model.safetensors (bf16, 3,008,627,352 B), tokenizer.json, tokenizer_config.json,
special_tokens_map.json.
Optimizer state is not included. Nanotron wrote an 18.05 GB AdamW state next to every
checkpoint (fp32 master weights + both moments, 974.80 GB across the 54 released checkpoints);
it is omitted from the release. These checkpoints are for inference and evaluation, not for
resuming training.
Step → epoch mapping
One optimizer step consumes 4 (micro) × 64 (accum) × 4 (DP) × 2048 = 2,097,152 tokens.
Table with columns: Directory, Nanotron step, Tokens consumed| Directory | Nanotron step | Tokens consumed |
|---|
epoch1 | 4770 | 10,003,415,040 |
epoch2 | 9540 | 20,006,830,080 |
epoch3 | 14147 | 29,679,738,880 |
This setting ends at step 14147, not 14305. Its topic quotas produced a 9.89B-token corpus rather than 10B, so three epochs are 14,147 steps.
Training configuration
Identical across all 18 runs (6 settings × 3 seeds).
Table | |
|---|
| Architecture | Llama 2, 28 layers, hidden 2048, FFN 5632 (SwiGLU), 16 heads (MHA) |
| Position / norm | RoPE θ = 10⁴, RMSNorm ε = 1e-5, tied embeddings |
| Vocabulary | 32,000 (Llama 2 tokenizer) |
| Parameters | 1,504,299,008 (1.504B; 1.439B non-embedding) |
| Optimizer | AdamW, β = (0.9, 0.95), ε = 1e-8, weight decay 0.1, grad clip 1.0 |
| LR schedule | peak 5e-4, 500-step linear warmup, WSD with linear decay to 0 over the final 10% |
| Batching | seqlen 2048, global batch 1024 sequences = 2.10M tokens/step |
| Precision | bf16 parameters, fp32 gradients and optimizer state |
Seeds 42/43/44 control initialization only — there is no dropout and the data order is fixed.
All six settings at a given seed start from bit-identical weights, released once as
KYS-Configs/nanotron/init/.
How these were produced
- A 100M-document pool was reservoir-sampled from DCLM-RefinedWeb and annotated with three
quality scorers and a 24-way WebOrganizer topic classifier →
KYS-DCLM-Refinedweb-100M-Scored.
- This setting's strategy selected source documents from the pool, which were rewritten with Qwen2.5-7B-Instruct via vLLM (greedy decoding) →
KYS-1.5B-Pretraining-Corpora.
- The corpus was tokenized and trained with Nanotron;
configs are in
KYS-Configs.
- Checkpoints were converted from Nanotron to HF format with the same converter used for the
paper's own evaluations. The conversion was verified by re-running LightEval on a converted
checkpoint and reproducing the paper's stored numbers exactly (
rw_piqa acc_norm 0.710555,
acc_norm 0.486158, delta 0.000e+00).
Evaluation
LightEval, 0-shot, acc_norm with continuation-token-length-normalized log-likelihood, on
ARC-Easy, HellaSwag, PIQA, SIQA, OpenBookQA, CommonsenseQA and MMLU (57 subsets). Task
definitions, launchers and all 276 raw result JSONs are in
KYS-Configs/eval/.
The rest of the release
Citation
@misc{kys2026,
title = {Know Your Sources: Data Selection Matters when Rewriting for Data-Constrained Pretraining},
author = {TODO},
year = {2026},
note = {TODO: fill in venue / arXiv id / URL}
}