Research Engineer, Character.ai

• We are looking for candidates with an abiding interest in how large models work, and the technical skills to advance our understanding of them
• Especially, we desire candidates with an unusual clarity of thought, and a capacity to think from first principles
• A bachelor's degree in a quantitative field (Physics, Mathematics, Computer Science); PhD preferred
• 2+ years experience in industry, training, evaluating, and meaningfully modifying models
• Working experience with at least one of PyTorch, Jax, or TensorFlow (not just high level APIs like keras.train)
• An excellent understanding of probability theory, linear algebra, and stochastic processes
• A healthy dose of skepticism about experimental results and interpretations, and a deep cynicism about published AI/ML research

Desirable

• We work closely with our data, pre-training, and post-training teams
• Run thousands of ablation and scaling experiments to understand underlying mechanisms in models
• Select model and architecture hyperparameters achieving best-possible tradeoffs in inference latency and model quality
• Determine the incremental value of additional human input in post-training