Alexander J Root

PhD Student Department of Computer Science Stanford University Email: ajroot [at] cs [dot] stanford [dot] edu Curriculum Vitae Google Scholar Github

I am a Stanford CS PhD student advised by Fredrik Kjolstad. I also work closely with Andrew Adams, Kayvon Fatahalian, and Jonathan Ragan-Kelley.

My research interests broadly include domain-specific languages, compilers, and architectures for high-performance numerical computing, with an emphasis on visual computing applications. I am particularly interested in performance and productivity: I aim to make it significantly easier to write high-performance code. I currently work on compilers for sparse array programming and high-performance spatial queries (e.g. ray tracing and collision detection).

I graduated with my bachelor’s (‘21) and master’s (‘22) from MIT, working under Jonathan Ragan-Kelley and Andrew Adams on vector instruction selection, fixed-point computing systems, and bounds inference. I also interned with Andrew, Shoaib Kamil, and Maaz Bin Safeer Ahmad at Adobe Research in the summers of ‘21 and ‘22, on the same topics. Part of my undergraduate work on fixed-point compute systems was advised by Frédo Durand.

Much of my pre-PhD research was applied to the Halide compiler, and I remain somewhat active in the language’s development.

I am generously supported by the NSF GFRP and a Stanford School of Engineering fellowship.

Publications

OOPSLA 2024		Compilation of Shape Operators on Sparse Arrays
		Proceedings of the ACM on Programming Languages, Volume 8, Issue OOPSLA
		Alexander J Root, Bobby Yan, Peiming Liu, Christophe Gyurgyik, Aart J.C. Bik, and Fredrik Kjolstad
		Paper Code
OOPSLA 2024		Compiler Support for Sparse Tensor Convolutions
		Proceedings of the ACM on Programming Languages, Volume 8, Issue OOPSLA
		Peiming Liu, Alexander J Root, Anlun Xu, Yinying Li, Fredrik Kjolstad, and Aart J.C. Bik
		Paper Code
ASPLOS 2023		Fast Instruction Selection for Fast Digital Signal Processing
		International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS)
		Alexander J Root, Maaz Bin Safeer Ahmad, Dillon Sharlet, Andrew Adams, Shoaib Kamil, and Jonathan Ragan-Kelley
		Paper Code
ASPLOS 2022		Vector Instruction Selection for Digital Signal Processors Using Program Synthesis
		International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS)
		Maaz Bin Safeer Ahmad, Alexander J Root, Andrew Adams, Shoaib Kamil, and Alvin Cheung
		Paper Code

Teaching

CS 343S: Domain-Specific Language Design Studio Teaching Fellow (TF), Spring 2024, Stanford University

CS 343D: Domain-Specific Programming Models and Compilers Course Assistant (CA), Winter 2023 and 2024, Stanford University

6.818: Dynamic Computer Language Engineering Teaching Assistant (TA), Fall 2021, MIT

6.006: Introduction to Algorithms Teaching Assistant (TA), Spring 2019 and 2020, MIT

MEET Computer Science Instructor, January 2019, MIT MEET (Global Teaching Labs)