Xiwen Zhang

Xiwen Zhang 张曦文

I work on machine learning and the systems that run it: protein structure prediction, fast image generation, and language models that reason well or run on small devices. These days I mostly teach computer science, one-on-one.

About

I studied Electronic Science and Technology at Shanghai Jiao Tong University, then received my M.S. in ECE from Purdue University, where I worked with Prof. Felix Xiaozhu Lin on video analytics for IoT cameras. I then joined the CS Ph.D. program at Georgia Tech, advised by Prof. Alexey Tumanov, and am currently on leave.

Since then I have worked in industry research, first as a research scientist at an AI drug discovery startup, and later at a GPU company on research collaborations with research institutes.

Research

Full list on Google Scholar
Predicted protein structure overlaid on the experimental structure
OmegaFold's prediction (purple) over the experimental structure (green) for CAMEO target 7EBQ:A.

Proteins

Predicting a protein's 3D shape from its amino-acid sequence, and what mutations do to it. OmegaFold makes high-resolution predictions from a single sequence, without the multiple sequence alignments that AlphaFold2 depends on. FastFold makes AlphaFold training and inference faster on GPU clusters. In a study of influenza neuraminidase, lab measurements of more than 6,000 mutations agreed well with fitness inferred by a protein language model.

High-Resolution de novo Structure Prediction from Primary Sequence (OmegaFold) Ruidong Wu, Fan Ding, Rui Wang, Rui Shen, Xiwen Zhang, Shitong Luo, Chenpeng Su, Zuofan Wu, Qi Xie, Bonnie Berger, Jianzhu Ma, Jian Peng bioRxiv 2022Paper
FastFold: Optimizing AlphaFold Training and Inference on GPU Clusters Shenggan Cheng, Xuanlei Zhao, Guangyang Lu, Jiarui Fang, Tian Zheng, Ruidong Wu, Xiwen Zhang, Jian Peng, Yang You PPoPP 2024arXivGitHub
Mutational Fitness Landscape of Human Influenza H3N2 Neuraminidase Ruipeng Lei, Andrea Hernandez Garcia, Timothy J.C. Tan, Qi Wen Teo, Yiquan Wang, Xiwen Zhang, Shitong Luo, Satish K. Nair, Jian Peng, Nicholas C. Wu Cell Reports 2023Paper
Diagram: reflow straightens trajectories so one-step generation succeeds
Reflow straightens the paths from noise to image, so a one-step model can learn them.

Fast image generation

Diffusion models turn noise into an image over many small steps. InstaFlow uses rectified flow to straighten that path, which makes it possible to distill Stable Diffusion into a generator that needs only one step.

InstaFlow: One Step Is Enough for High-Quality Diffusion-Based Text-to-Image Generation Xingchao Liu, Xiwen Zhang, Jianzhu Ma, Jian Peng, Qiang Liu ICLR 2024arXivGitHub
Plot of responses per query, by query difficulty
With Prop2Diff, DART-Math collects more responses for harder questions (hardest on the left).

Language models

Training models to reason better, in math and across text and images, and measuring how small language models actually run on phones and other edge devices.

Diving into Self-Evolving Training for Multimodal Reasoning Wei Liu, Junlong Li, Xiwen Zhang, Fan Zhou, Yu Cheng, Junxian He ICML 2025arXivGitHub
Demystifying Small Language Models for Edge Deployment Zhenyan Lu, Xiang Li, Dongqi Cai, Rongjie Yi, Fangming Liu, Wei Liu, Jian Luan, Xiwen Zhang, Nicholas D. Lane, Mengwei Xu ACL 2025PaperGitHub
DART-Math: Difficulty-Aware Rejection Tuning for Mathematical Problem-Solving Yuxuan Tong, Xiwen Zhang, Rui Wang, Ruidong Wu, Junxian He NeurIPS 2024arXivGitHub

Also: PhoneLM: An Efficient and Capable Small Language Model Family through Principled Pre-training (arXiv 2024) and On the Perception Bottleneck of VLMs for Chart Understanding (arXiv 2025).

Diagram of how Elf schedules counting on a camera within an energy budget
Elf plans how a camera counts objects over time within an energy budget.

Earlier work

Video analytics on energy-constrained IoT cameras, deep learning for identifying wireless interference, and visual analytics for hyperspectral images.

Approximate Query Service on Autonomous IoT Cameras Mengwei Xu, Xiwen Zhang, Yunxin Liu, Gang Huang, Xuanzhe Liu, Felix Xiaozhu Lin MobiSys 2020PDFarXiv
Deep Learning for Interference Identification: Band, Training SNR, and Sample Selection Xiwen Zhang, Tolunay Seyfi, Shengtai Ju, Sharan Ramjee, Aly El Gamal, Yonina C. Eldar IEEE SPAWC 2019PDFarXiv
FeatureExplorer: Interactive Feature Selection and Exploration of Regression Models for Hyperspectral Images Jieqiong Zhao, Morteza Karimzadeh, Ali Masjedi, Taojun Wang, Xiwen Zhang, Melba M. Crawford, David S. Ebert IEEE VIS 2019PDFarXiv

Also: Deep Learning for Frame Error Prediction using a DARPA Spectrum Collaboration Challenge (SC2) Dataset (IEEE Networking Letters 2021) and Efficient Training of Deep Classifiers for Wireless Source Identification using Test SNR Estimates (IEEE Wireless Communications Letters 2020).

Teaching

Alongside research, I have taught more than 3,000 hours of one-on-one lessons in university computer science, math and statistics. That covers 150+ courses at 40+ universities, for students in Australia, the UK, Hong Kong, Singapore and North America.

I start from where a student is stuck, explain down to the mechanism, and move on only once they can explain it back.

给同学和家长

教过哪些课、怎么上课、怎么联系我,都写在中文辅导主页上。

打开中文辅导主页

Education

Georgia Institute of Technology Ph.D. program in Computer Science, on leave Atlanta, GA
Purdue University M.S. in Electrical and Computer Engineering West Lafayette, IN
Shanghai Jiao Tong University B.S. in Electronic Science and Technology Shanghai