Projects

Research

Cross-Entropy Games and Frost Training

Preprint, 2026

Arthur Renard, Franck Gabriel, Valentin Hartmann, Clément Hongler

Xent Labs · Université Lyon 1

Frost Training improves Monte Carlo policy optimization for Cross-Entropy Games by exploiting the gradient of the reward in embedding space. The signal behind the GCG jailbreaking technique is repurposed to boost training: applied to GRPO for maximum-likelihood infilling, it reaches higher best-of-k scores faster.

LLMsGRPOReinforcement Learning
Cross-Entropy Games and Frost Training

Cognitive Training for Language Models

Preprint, 2026

Clément Hongler, Franck Gabriel, Valentin Hartmann, Arthur Renard, Andrew Emil

Xent Labs

A framework for automatically growing a curriculum of tasks that builds general capabilities in language models through relevant skill discovery. Using Cross-Entropy Games, the paper shows that greedy curriculum learning admits essentially a single meta-objective (up to a few hyper-parameters), yielding a principled process called cognitive training.

LLMsCurriculum LearningOptimization
Cognitive Training for Language Models

Boolformer

AI for Math Workshop, ICML 2025

Stéphane d'Ascoli*, Arthur Renard*, Emmanuel Abbé, Clément Hongler, Vassilis Papadopoulos, Josh Susskind, Samy Bengio (* equal contribution)

EPFL · Apple

A Transformer trained end-to-end for symbolic regression of Boolean functions. Predicts compact formulas from truth tables, remains robust to noisy or partial observations, and is competitive with state-of-the-art genetic algorithms on gene regulatory network inference at orders-of-magnitude lower cost.

TransformersSymbolic RegressionInterpretable ML
Boolformer

Phase Transition Finder

GECCO Companion 2024

Vassilis Papadopoulos, Guilhem Doat, Arthur Renard, Clément Hongler

EPFL

An algorithm that efficiently locates parameters at the border between phases in high-dimensional dynamical systems. Applied to Lenia, it doubles the frequency of interesting emergent behaviours while remaining tractable for large-scale searches.

Complex SystemsArtificial LifePyTorch
Phase Transition Finder

Personal

Für Elise
note(`e5 d#5 e5 d#5 e5
      b4 d5 c5 a4`)
  .s("piano")

Type a song name, get an editable instrumental loop in Strudel. Compiled from open transcriptions, no LLM involved.

StrudelMIDITypeScript

A practical write-up on fine-tuning FLUX.1-dev with LoRA for personalised image generation.

FLUX.1LoRAFlow Matching

Other work

  • Designed and shipped the official website and mobile app for Europe's largest student festival (15,000+ attendees), with live schedules, maps, and artist information.

    Next.js · TypeScript · Strapi