Whetstone-124M Continued Pretraining (4B)

A 123,694,080-parameter base language model created by continued pretraining of Whetstone-124M-Base. It is a plain next-token predictor, not instruction-tuned and not safety-tuned. The release checkpoint is step-00007632, after 4.0B continuation tokens (7,632 steps) following the baseline's 2.5B-token pretraining.

Release: Apache-2.0 weights; intended public repository harsimran2004/whetstone-124m-continued-4b. This folder was prepared locally before publication.

Quick start

from transformers import AutoModelForCausalLM, AutoTokenizer

tokenizer = AutoTokenizer.from_pretrained("harsimran2004/whetstone-124m-continued-4b")
model = AutoModelForCausalLM.from_pretrained("harsimran2004/whetstone-124m-continued-4b")
inputs = tokenizer("The history of the printing press began", return_tensors="pt")
output = model.generate(**inputs, max_new_tokens=50, do_sample=True, temperature=0.7, top_k=40)
print(tokenizer.decode(output[0], skip_special_tokens=True))

The weights are standard LlamaForCausalLM; trust_remote_code is not needed. Documents were separated by <eos> (id 32001); no <bos> was used in training. The tokenizer does not add a BOS token. For corpus-text behavior when special-token strings appear inside a document, load with split_special_tokens=True.

Model

Architecture decoder-only Transformer / LlamaForCausalLM: pre-norm RMSNorm, SwiGLU, RoPE, no biases, tied embeddings
Parameters 123,694,080
Layers / width / heads 14 / 768 / 12 (head dim 64; full multi-head attention)
MLP hidden size 2048
Context 2,048 tokens
RoPE theta 10,000
Vocabulary 32,007: 32,000 byte-level BPE + <bos> 32000, <eos> 32001, <pad> 32002, &lt;&vert;im_start&vert;&gt; 32003, &lt;&vert;im_end&vert;&gt; 32004, <think> 32005, </think> 32006
Weights float32 model.safetensors

Training data and recipe

The baseline was trained on 2.5B tokens. This checkpoint was warm-started from baseline step 4,750 and trained on 4.0B more tokens from 4.13B packed continuation tokens. The tokenizer and architecture were unchanged. New documents were deduplicated against the original corpus and within the new corpus.

Continuation source Token share Details
FineWeb-Edu 55% web/educational text
github-code-clean 20% permissive-subset: MIT, Apache-2.0, BSD, ISC, CC0, or Unlicense
OpenWebMath 15% mathematical web text
FinePDFs-edu 10% English, keyword-filtered technical PDF-derived text

Training used AdamW (betas 0.9, 0.95; weight decay 0.1; gradient clipping 1.0), bf16 mixed precision, a 524,288-token batch, and one spot A100. Learning rate warmed up for 200 steps to 3e-4, then decayed cosine to 3e-5. The run was interrupted by a full disk near step 5,090, resumed from step 5,088, and ended at step 7,632.

Data and licence limits: StarCoderData was not used. The per-file code licences cannot be audited from the final data because the permissive filter was applied at build time and final records do not retain per-file licence fields. PDF-derived text is ODC-By, but the underlying documents retain their own copyright.

Continued pretraining loss

Evaluation

Full held-out evaluation uses 11,278 rows for the original held-out set and 7,308 rows for the new-mix held-out set. Loss is nats/token (lower is better).

Measure Baseline Continued
Original held-out 1.6629 1.6198
New-mix held-out 1.8141 1.6917
FineWeb-Edu 1.963 1.846
Code 1.225 1.131
OpenWebMath 2.030 1.902
Technical PDFs 1.893 1.708

Zero-shot results use log-likelihood of answer endings: HellaSwag acc_norm, ARC-Easy acc, ARC-Challenge acc_norm, PIQA acc.

Model HellaSwag ARC-Easy ARC-Challenge PIQA Average
Whetstone-124M baseline 29.3 44.0 24.3 59.8 39.4
Whetstone-124M continued 30.6 49.0 24.5 60.0 41.0
GPT-2 124M 31.4 43.9 22.8 63.1 40.3

Standard errors are about 0.4 / 1.0 / 1.2 / 1.1 points respectively. The continued model is 9.5 points below SmolLM-135M on this four-task average. The commonsense gap to GPT-2 on HellaSwag and PIQA is mostly still present.

Baseline-to-continued benchmark scores

Decontamination

A post-evaluation scan found verbatim 13-word overlaps with test sets: 0.4% of HellaSwag and ARC-Easy items, 0.5% of PIQA, and 6.7% of ARC-Challenge (78 items). All 78 ARC-Challenge items came from one OpenWebMath page: the Hugging Face ai2_arc dataset preview. Removing flagged items changes no gain by more than 0.1 point. This detects verbatim overlap only, not paraphrases, translations, or answer keys elsewhere.

Limitations and intended use

Intended for research on small-model pretraining, training/evaluation experiments, and fine-tuning. Not intended for chat, factual question answering, or any use where wrong text could cause harm. It can produce fluent falsehoods and incorrect code.

This is one run and one seed. There is no code benchmark and no knowledge/QA test. Differences near the reported standard errors are uncertain. This model is English and web-centric; it received no instruction tuning or safety training.

Package evidence

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