Now Solving: Global Optimal AI

We focus on Scalable Optimization, Learning, and Intelligent Decision-making (SOLID).


SOLID Lab is based in the Department of Chemical and Biological Engineering at The University of British Columbia .


Explore Our Research Meet Our People

Latest Highlight

Jiayang received the Wall Research Award.  | June 2025

Prof. Yankai Cao gave a talk at the MIT PSE Seminar.  | May 2025

Congratulations to Jingyi on her PhD graduation!  | April 2025

Jason Zhao received the Four Year Doctoral Fellowship.  | March 2025

Yixiu Wang has published a paper in Nature communication as a co-first author. The paper has been cited for more than 500 times.  | April 2022

→ More lab news

Recruiting

We are seeking future postdoctoral researchers, graduate students, visiting students, and undergraduate students. → Join Us


Research

SOLID Lab focuses on the design and implementation of large-scale local and global optimization algorithms to solve problems that arise in diverse decision-making paradigms such as machine learning, stochastic optimization,and optimal control. Our algorithms combine mathematical techniques and emerging high-performance computing hardware to achieve computational scalability. We make these developments accessible to academic and industrial users by implementing algorithms on easy-to-use and extensible software libraries.

The problems that we are addressing are of unprecedented complexity and defy the state-of-the-art. For example, in our recent work, we developed a novel global optimization algorithm capable of solving k-center clustering problems (an unsupervised learning task) with up to 1 billion samples, while state-of-the-art approaches in the literature can only address several thousand samples.

We are currently using our tools to address engineering and scientific questions that arise in diverse application domains, including optimal decision trees, optimal clustering, deep-learning-based control, optimal power system planning, AI for bioprocess operation, and optimal design of zero energy buildings.

Selected Publications → See Full Publications

Differentiable Decision Tree via ``ReLU+Argmin'' Reformulation. Advances in Neural Information Processing Systems (NeurIPS), Spotlight Paper, 2025.
A scalable deterministic global optimization algorithm for training optimal decision tree. Advances in Neural Information Processing Systems (NeurIPS) 35, 8347-8359, 2022.
Global optimal k-medoids clustering of one million samples. Advances in Neural Information Processing Systems (NeurIPS) 35, 982-994, 2022.
Global optimization of k-center clustering. International Conference on Machine Learning (ICML), Spotlight Paper, 19956-19966, 2022.
A Scalable deterministic global optimization algorithm for clustering problems. International Conference on Machine Learning (ICML),Spotlight Paper, 4391-4401, 2021.

SOLID Lab

We focus on Scalable Optimization, Learning, and Intelligent Decision-making (SOLID). SOLID Lab is based in the Department of Chemical and Biological Engineering at The University of British Columbia.

Contact US

Yankai Cao
Associate Professor
Tel: 1 604 822 1346
Email: yankai.cao@ubc.ca
Office: CHBE 237
2360 East Mall
Vancouver, BC, Canada