Lumen-v2-130M-Base πŸ’‘

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License: Apache 2.0 Parameters Tokens Context

Lumen-v2-130M-Base is a high-efficiency Causal Language Model pretrained completely from scratch on a curated 6 Billion token multi-source educational corpus using Google TPU v5e-8.

The model features an 11-layer architecture with tied input/output embeddings, 4 full-rank Value Embedding (ResFormer) memory tables, causal depthwise convolution mixing (Canon K=3), and a single-digit tokenized vocabulary.


πŸ“Š Benchmark Results

All evaluations are zero-shot, evaluated with standard length-normalized likelihood (acc_norm) or raw accuracy over the full official test sets. Prompts are evaluated with the prefix <|bos|> token matching the pretraining distribution.

Core Benchmarks

Benchmark Metric Score Samples ($n$)
ArithMark-3 acc 69.30% 1,000
PIQA acc_norm 63.33% 1,838
ARC-Easy acc_norm 47.81% 2,376
ARC-Challenge acc_norm 26.37% 1,172
HellaSwag acc_norm 35.21% 10,042
LAMBADA (OpenAI) acc 33.88% 5,153
BLiMP (Grammar) acc 78.90% 67,000
WikiText-2 bits-per-byte (bpb) 0.9739 β€”

Extended Task Breakdown

Task Evaluation Metric Score
SciQ acc_norm 77.10%
COPA acc 70.00%
BoolQ acc 56.09%
SWAG acc_norm 51.57%
WinoGrande acc 50.91%
TruthfulQA MC2 acc 42.27%
OpenBookQA acc_norm 32.40%
RACE acc 30.05%
CommonsenseQA acc 19.90%
MMLU acc 23.09%
WikiText-2 word_perplexity 36.96

🍌 BananaMind Base Bench 1.1

Zero-shot evaluation on the BananaMind Base Bench 1.1 β€” a 350-example text-completion benchmark for base causal language models. Evaluation uses mean conditional log-probability scoring with no BOS token (official benchmark standard).

Metric Score
Overall Elo 1022
Raw Accuracy 54.86% (192/350)
Weighted Accuracy 50.86%

Category Breakdown

Category Elo Accuracy
Language Completion 1376 96.00% (48/50)
Commonsense 1072 70.00% (35/50)
World Knowledge 1074 70.00% (35/50)
Context Tracking 869 36.00% (18/50)
Quantitative 747 16.00% (8/50)
Logical Reasoning 1021 44.00% (22/50)
Code Completion 1131 52.00% (26/50)

πŸ“Œ Pretraining Data & Decontamination

The model was pretrained on 5,999,951,872 tokens across a balanced educational blend:

Source Share Tokens Description
HuggingFaceTB/smollm-corpus (fineweb-edu-dedup) 72.0% 4.32 B High-quality educational web corpus filtered by classifier score.
HuggingFaceTB/smollm-corpus (cosmopedia-v2) 10.0% 600 M Synthetic textbooks, lectures, and articles across broad taxonomies.
HuggingFaceTB/finemath (finemath-4plus) 7.0% 420 M Mathematical web pages, derivations, and proofs.
Procedural Arithmetic 5.0% 300 M Algorithmic story problem generator with diverse entities and numbers.
roneneldan/TinyStories 3.0% 180 M Synthetic narratives with constrained vocabulary for syntactic coherence.
microsoft/orca-math-word-problems-200k 3.0% 180 M Grade-school math word problems with step-by-step solutions.

Decontamination Protocol

Full-corpus 13-gram exact-match filtering. All six mix sources were scanned with an Aho-Corasick automaton of 5,288,966 normalized 13-word phrases built from the test and validation splits of every benchmark reported in this card plus GSM8K (HellaSwag, ARC-Easy/Challenge, PIQA, LAMBADA, WikiText-2, SciQ, COPA, BoolQ, SWAG, WinoGrande, TruthfulQA, OpenBookQA, RACE, CommonsenseQA, MMLU, GSM8K, ArithMark-3). 7,590 rows (0.096% of the corpus) were removed across all sources; a post-cut re-scan found zero residual 13-gram overlaps. The released weights were retrained from scratch on the cleaned mix (identical architecture, tokenizer, data order and schedule; the ArithMark-3 generator itself has 0 exact / 0 digit-skeleton / 0 n-gram collisions with the benchmark by construction, and the held-out ArithWord split scores 86.95% vs 69.30% on the benchmark β€” generalization, not template recall).


πŸ—οΈ Architecture & Specifications

Parameter Value
Architecture Causal Decoder-Only Transformer (GQA + Tied Weights)
Inference Parameters 127,977,104 (~128M)
Layers 11
Hidden Size (d) 768
Feed-forward Dimension 3072 (ReLUΒ² activation)
Attention Heads 6 Query / 2 KV (GQA 3:1), Head Dim 128
Positional Encoding RoPE (theta = 100,000)
Normalization Parameter-free RMSNorm (pre-norm), with per-head QK-norm
Context Window 2048 tokens
Vocabulary Size 32,768 (single-digit byte-level BPE)
Weight Tying Enabled (wte.weight == lm_head.weight)
Value Embeddings 4 full-rank ResFormer tables on deepest layers
Local Mixing Causal depthwise 1D convolution (K=3)
Auxiliary Loss Multi-Token Prediction (MTP t+2, weight 0.3, train-only)
Hardware Google TPU v5e-8 (128 GB HBM2e)
Training Speed 360,000 tokens/sec (4.5 hours wall-clock time)

πŸ’» Quickstart (Transformers)

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "kefir090/Lumen-v2-130M-Base"

tokenizer = AutoTokenizer.from_pretrained(model_id, trust_remote_code=True)

# bfloat16 needs compute capability >= 8.0 (Ampere or newer: RTX 30xx+, A100/H100).
# T4/P100 report is_bf16_supported()==True but produce wrong results -- check cc instead.
if torch.cuda.is_available():
    major, _ = torch.cuda.get_device_capability()
    dtype = torch.bfloat16 if major >= 8 else torch.float32
else:
    dtype = torch.float32

model = AutoModelForCausalLM.from_pretrained(
    model_id,
    dtype=dtype,
    device_map="auto",
    trust_remote_code=True,
)

prompt = "The solar system consists of"
inputs = tokenizer(prompt, return_tensors="pt").to(model.device)

with torch.no_grad():
    outputs = model.generate(
        **inputs,
        max_new_tokens=80,
        do_sample=True,
        temperature=0.7,
        top_p=0.85,
        repetition_penalty=1.15,
    )

print(tokenizer.decode(outputs[0], skip_special_tokens=True))

Transformers version: tested with transformers>=4.57, including the latest 5.x line. Older releases may fail to load the custom architecture correctly.

Note: This is a pretrained base foundation model. It performs autoregressive text completion and is not instruction-tuned.


πŸ“œ License

This model and its weights are released under the Apache 2.0 License.

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