Stability AI India AI Research Engineer Interview: Rounds, Questions and Preparation

What the job involves

AI Research Engineers at deep tech companies like Stability AI India work on designing, training, and fine-tuning generative models, often focusing on diffusion models, large language models, or multimodal systems. They run experiments, implement research papers, and collaborate with product teams to turn prototypes into scalable AI features. The role blends deep learning theory with strong engineering practices, including distributed training and model optimization.

Role and technical knowledge

1. 1

   Explain the training objective of a diffusion model and how it differs from a GAN.

   Cover the denoising score matching or variational lower bound, and contrast with adversarial training. Mention stability and mode coverage.

2. 2

   How does self-attention work in a transformer, and why is it effective for generative tasks?

   Describe queries, keys, values, and scaled dot-product attention. Highlight parallelization and long-range dependency capture.

3. 3

   What is the role of the KL divergence in variational autoencoders?

   Explain the evidence lower bound and how KL regularizes the latent space. Mention the trade-off with reconstruction loss.

4. 4

   How would you fine-tune a large pretrained diffusion model on a small custom dataset?

   Discuss LoRA, DreamBooth, or textual inversion. Mention freezing most weights and training adapters to avoid overfitting.

Practical scenarios and problem solving

1. 5

   Your model generates high-quality images but training loss plateaus early. How do you debug?

   Check learning rate, data augmentation, model capacity, and gradient norms. Suggest monitoring validation metrics and trying warmup or different schedulers.

2. 6

   You need to train a 1B parameter model on 4 GPUs. Outline your distributed training strategy.

   Mention data parallelism with DDP, gradient accumulation, mixed precision, and possibly ZeRO stage 2. Discuss communication overhead.

3. 7

   How would you evaluate the quality of generated images beyond FID?

   Propose precision and recall, CLIP score, human evaluation, and diversity metrics. Note FID's limitations with small samples.

4. 8

   A research paper claims a new attention variant improves long-context generation. How do you validate it?

   Suggest reproducing on a standard benchmark, running ablations, and checking compute budget. Emphasize statistical significance and error bars.

Behavioural and research culture

1. 9

   Tell me about a time you had to learn a new ML concept quickly for a project.

   Use STAR format. Highlight resourcefulness, reading papers, and applying the concept to a concrete outcome.

2. 10

   Describe a situation where your experiment failed. What did you do?

   Show ownership, analysis of failure, and iterative improvement. Mention what you changed and what you learned.

3. 11

   How do you stay updated with the latest AI research, and which recent paper excited you?

   Mention specific conferences, arXiv, or blogs. Discuss one paper's method and potential impact, showing genuine curiosity.

4. 12

   Why do you want to work on generative AI at a deep tech company rather than a general software role?

   Connect personal interest in generative models to the company's mission. Show awareness of challenges like safety and scalability.

HR and motivation

1. 13

   Where do you see yourself in three years as an AI Research Engineer?

   Align growth with deeper research expertise and contributing to impactful projects. Avoid vague answers like 'manager'.

2. 14

   How do you handle tight deadlines when running multiple experiments?

   Discuss prioritization, automation of routine tasks, and clear communication. Mention using experiment tracking tools.

3. 15

   Are you comfortable working in a hybrid or remote setup with a global research team?

   Show adaptability and experience with asynchronous communication. Mention tools like Slack, Notion, or Git.

4. 16

   What are your salary expectations for this role?

   Research typical fresher AI research salaries in India. Give a range and express flexibility based on overall compensation.