Daily research notes18 min read

Accurate Judges, Useful Teachers

Generative reward models · Rollout consistency · Reading Mamba

Two close readings separate static judging accuracy, online learning outcomes, and implementation mismatch; seven briefs cover compute, data, and models from the overlap window. The classic is Mamba: choosing what to write and computing it in parallel.

Scaling lawsMuonPost-trainingRNN / linear attention
Daily classic · 2024Mamba
Close readingRead §§2–4 and Appendices B.2–B.4; not reproduced

Static accuracy and online reward quality are different objectives

Scaling Laws for Generative Reward Models
Angel Raychev · Nathan Lile · Rafael Rafailov
First posted October 22, 01:37 EDT · v1; overlap-window catch-up

Following reward overoptimization (Gao et al., 2022), correctly judging story preferences on a fixed distribution need not guide an evolving policy. The paper compares SFT Answer-Only and GRPO Thinking judge pipelines in creative writing.[1]

Fixed Gold-oriented response pair; + uses the Gold label and − its flip
Δθ=log⁡πθ(y+∣x)πref(y+∣x)−log⁡πθ(y−∣x)πref(y−∣x),ℓ+=−log⁡σ(βΔθ),ℓ−=−log⁡σ(−βΔθ)\Delta_\theta=\log\frac{\pi_\theta(y^+\mid x)}{\pi_{\rm ref}(y^+\mid x)}-\log\frac{\pi_\theta(y^-\mid x)}{\pi_{\rm ref}(y^-\mid x)},\quad \ell_+=-\log\sigma(\beta\Delta_\theta),\quad\ell_-=-\log\sigma(-\beta\Delta_\theta)
Appendix B.3 identity: which pairs are mislabeled, their gradient directions, and magnitudes matter
∇θℓ−−∇θℓ+=β∇θΔθ\nabla_\theta\ell_- -\nabla_\theta\ell_+=\beta\nabla_\theta\Delta_\theta

Online sampling and filtering invalid or conflicting judge votes also change the retained-pair distribution. The identity is an explanation; the paper does not measure a per-pair gradient decomposition.[1]

SettingObservation
Qwen3 judges 0.6B–14B; policies 0.6B–8BThinking has higher static accuracy
Fixed learned 32B Gold evaluatorAnswer-Only has higher peak/top-five Elo in 7 of 8 matched settings
Another learned judge, 80 pairsAnswer-Only wins 42; inconclusive overall
The ranking reversal is conditional on these training and evaluation pipelines.[1]
Descriptive scaling fit: P and R are billions of parameters; M indicates Thinking
Y=b0+bPlog⁡P+bRlog⁡R+bMM+bMPMlog⁡P+bMRMlog⁡R+ϵY=b_0+b_P\log P+b_R\log R+b_M M+b_{MP}M\log P+b_{MR}M\log R+\epsilon
Close readingRead Day-0 RL support and adjacent implementation details; not reproduced

Low-precision RL: three checks before treating implementations as one policy

vLLM Delivers Day-0 Support for MiniMax-M3.1-Flash
Inferact and the vLLM Team
Technical blog published/updated October 23

The training section combines an NVFP4 checkpoint with veRL, FSDP2, and LoRA, freezing base experts and syncing adapters. Before training it checks weight transfer, expert-routing replay, and same-token logprobs: equal weights can still yield different execution.[2]

Explanatory notation for token-level IS; the source specifies a ratio cap of 2
wt=ptrainer(at∣ht)prollout(at∣ht),wˉt=min⁡{2,wt}w_t=\frac{p_{\rm trainer}(a_t\mid h_t)}{p_{\rm rollout}(a_t\mid h_t)},\qquad \bar w_t=\min\{2,w_t\}

Each batch receives one optimizer step, using rollout logprobs as old logprobs and skipping a recomputation forward pass. This condition does not directly transfer to multiple reuse epochs or more stale training.[2]

Setup / metricStart → end
DAPO-Math-17K; 16×GB300200 GRPO steps
AIME-2024 accuracy36.3% → 67.5%
Train/rollout KL0.040 → 0.024
Original blog report; no separate ablation of these consistency measures is provided here.[2]
BriefRead abstract and pretraining overview; not all evaluations audited

Muon, μP, and data scheduling in a 320B MoE recipe

320B total / 15B active parameters; pretraining combines Stable SplitNorm, Muon, and μP, increasing the coding mixture later. The report emphasizes a margin between safe and optimal learning rates; it does not isolate Muon’s causal contribution.[3]

BriefBased on the original abstract

Joint scaling of continuous semantics and discrete generation

Cola2: Co-Adaptive Hierarchical Language Modeling with Continuous Semantic Compression and Balanced Discrete Generation
Hongcan Guo · Yian Zhao · Feng Wang · Shen Nie · Guoqiang Wei · Yan Zeng · Hengshuang Zhao
October 22, 10:04 EDT · v1

Dynamic semantic segmentation lets token prediction update the encoder while stop-gradient decouples the flow prior. Experiments at about 210B tokens examine design and scaling; an unconverged model with 346.03B source tokens averages 60.10 over eight tasks. Cross-model token differences do not establish a compute-matched advantage.[4]

BriefBased on the original abstract

Data sources: control priors without robot trajectories

Learning Robot Behavior Priors from Non-Robotic Synthetic Data
Mateusz Odrowaz-Sypniewski et al.
October 22, 09:43 EDT · v1

Three procedural control abstractions train a Transformer with nontrivial zero-shot action prediction on unseen robot tasks. A compute-matched real-data baseline is stronger only on its training datasets. This compares data sources and transfer, not a universal robot scaling law.[5]

BriefBased on the original abstract

Data quality and trainable parameters at fixed token budgets

AQL-Lite: Enabling Efficient Knowledge Acquisition for Arabic LLMs via Data-Centric Continual Pretraining
Houssam Eddine Boukhalfa · Mourad Bouache · Mourad Dahmane
October 21, 15:04 EDT · v1

At a matched 1B tokens, curated data improves the four-task mean by 3.51 points over raw web. At 5B tokens, partial-parameter training recovers 94% of full-CPT gain in 52% of wall time; means are 73.19 vs 73.58. Recovery is the incremental gain over base, not retention of 94% of all capabilities.[6]

BriefBased on the original abstract

VANE: next-frame prediction in a fixed semantic space

With a frozen semantic tokenizer, a causal encoder predicts the next full-frame embedding and an auxiliary decoder preserves detail. The paper reports model/data scaling and a 7.1-point gain over V-JEPA 2.1 in EPIC-KITCHENS-100 anticipation mean-class recall@5; strict budget matching is not specified in the abstract.[7]

BriefBased on the original abstract

Scene coverage and data scaling for closed-loop navigation

94 reconstructed scenes, 94K demonstrations, and 46.5M observation-state-action samples. Scaling ACT training from 5 to 70 scenes raises seen/unseen median success from 30.6% to 41.2% and 16.8% to 29.4%. Offline prediction error is not interchangeable with closed-loop success.[8]

BriefAbstract and version dates verified; substantive version differences unverified

Author watch: collaborative compute in software worlds

World of SWECraft: Agent Collaboration at Scale via Simulated Software Worlds
Shannon Zejiang Shen et al. · Luke Zettlemoyer
First posted October 16; v2 October 21, 13:59 EDT

Multi-agent collaboration is evaluated through hidden downstream efficiency in dependent Python packages: three worlds, eight models, and over 10,000 agent-hours, with reported gains up to 31%. Included for Luke author tracking; these conclusions are not claimed as additions in v2.[9]

Daily classic · Historical workRead §2, §§3.1–3.5, Theorem 1, and §4.1 task setups; kernel benchmarks not reproduced

Choose what to retain before compressing history

Mamba: Linear-Time Sequence Modeling with Selective State Spaces
Albert Gu · Tri Dao
First posted 2023-12-01; COLM 2024; read v2, 2024-05-31
COLM 2024 Outstanding Paper Award ↗

S4 (2022) compresses history with a fixed linear system; linear attention (2020) accumulates a finite state. Which language tokens deserve memory depends on content. Mamba (2024) makes writing, reading, and forgetting input-dependent.[10]

Single-channel notation: N-dimensional state and fixed diagonal A; the layer runs across D channels
ht=Aˉtht−1+Bˉtxt,yt=Ctht,Bt=sB(xt), Ct=sC(xt), Δt=softplus⁡(b+sΔ(xt))h_t=\bar A_t h_{t-1}+\bar B_t x_t,\quad y_t=C_t h_t,\qquad B_t=s_B(x_t),\ C_t=s_C(x_t),\ \Delta_t=\operatorname{softplus}(b+s_\Delta(x_t))
Zero-order-hold discretization; singular cases admit a continuous extension
Aˉt=eΔtA,Bˉt=(ΔtA)−1(eΔtA−I)ΔtBt\bar A_t=e^{\Delta_t A},\qquad\bar B_t=(\Delta_t A)^{-1}(e^{\Delta_t A}-I)\Delta_t B_t
Scalar special case of Theorem 1: exp(−softplus(z))=1−sigmoid(z)
N=1,A=−1,B=1,Δt=log⁡(1+ezt)⟹ht=(1−gt)ht−1+gtxt,gt=σ(zt)N=1,\quad A=-1,\quad B=1,\quad\Delta_t=\log(1+e^{z_t})\quad\Longrightarrow\quad h_t=(1-g_t)h_{t-1}+g_tx_t,\quad g_t=\sigma(z_t)

A small gate retains state and ignores the current input; a large gate resets toward it. This scalar interpretation is not a convergence theorem for the full network. Input-dependent coefficients break fixed convolution but preserve associativity of affine composition.[10]

Equivalent algebraic explanation of scan; associativity follows from affine composition
Ft(h)=at⊙h+bt,(a2,b2)∘(a1,b1)=(a2⊙a1, a2⊙b1+b2)F_t(h)=a_t\odot h+b_t,\qquad (a_2,b_2)\circ(a_1,b_1)=(a_2\odot a_1,\ a_2\odot b_1+b_2)

A parallel prefix scan is therefore possible. The implementation fuses discretization and recurrence in SRAM and recomputes states in backward, avoiding the full B×L×D×N state tensor in HBM. Selection and hardware-aware execution jointly support linear sequence complexity.[10]

READ THE ORIGINALS

Original sources

  1. GenRM: methodology, online experiments, and Appendix B limitations
  2. Original vLLM blog: Day-0 RL support
  3. IQuest-Q1: pretraining overview
  4. Cola2 original abstract
  5. Robot-prior original abstract
  6. AQL-Lite original abstract
  7. VANE original abstract
  8. AirPlayground original abstract
  9. SWECraft abstract and version record; differences unverified
  10. Historical Mamba: §§2–3 and §4.1
  11. COLM 2024 official award list
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2026-10-21 08:09 — 2026-10-24 08:09 · America/New_York

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