Hello!

I'm an NSF Postdoc in the math department at UC Berkeley, working broadly in numerical analysis, (randomized) numerical linear algebra, and scientific computing. My mentor is James Demmel.

Before moving to Berkeley, I completed a Ph.D. in mathematics at UC San Diego, where my advisor was Ioana Dumitriu. I was also a Measurement Science and Engineering Fellow in the Applied and Computational Math Division of NIST, working primarily with Barry Schneider. In 2018 I completed a B.A. in mathematics at Washington University in St. Louis.

My preferred pronouns are he/him. 🏳️‍🌈

Publications

Preprints:

James Demmel, Inderjit Dhillon, Sai Surya Duvvuri, Julien Langou, Osni Marques, and R.S. DBDSVDMR3: An MRRR-Based Bidiagonal SVD Solver Built from DSTEGR (2026) [arXiv].
Ioana Dumitriu, Olga Holtz, Abraham Hsu, Nicholas Liskij, Yoav Moran, R.S., Oded Schwartz, and Shuncheng Yuan. Fast and Stable Arbitrary Precision Approximate Matrix Multiplication (2026) [arXiv].
James Demmel, Hengrui Luo, R.S., and Yifu Wang. Minimizing the Arithmetic and Communication Complexity of Jacobi's Method for Eigenvalues and Singular Values: Part Two - Parallel Algorithms (2026) [arXiv].

Journal Papers:

James Demmel, Ioana Dumitriu, and R.S. Structured Divide-and-Conquer for the Definite Generalized Eigenvalue Problem. To appear in SIAM Journal on Matrix Analysis and Applications [arXiv].
James Demmel, Hengrui Luo, R.S., and Yifu Wang. Minimizing the Arithmetic and Communication Complexity of Jacobi's Method for Eigenvalues and Singular Values: Part One - Serial Algorithms. To appear in IMA Journal of Numerical Analysis [arXiv].
James Demmel, Ioana Dumitriu, and R.S. Fast and Inverse-Free Algorithms for Deflating Subspaces. Linear Algebra and its Applications (2026) [journal] [arXiv].
R.S. and Heman Gharibnejad. Numerical Methods for the Time-Dependent Schrödinger Equation: Beyond Short-Time Propagators. Atoms - Special issue in memory of Barry I. Schneider (2025) [journal].
James Demmel, Ioana Dumitriu, and R.S. Generalized Pseudospectral Shattering and Inverse-Free Matrix Pencil Diagonalization. Foundations of Computational Mathematics (2024) [journal] [arXiv] [code].
R.S., Heman Gharibnejad, and Barry I. Schneider. ITVOLT: An Iterative Solver for the Time-Dependent Schrödinger Equation. Computer Physics Communications Vol. 291 (2023) [journal] [arXiv] [code].

Other:

Linear Systems and Eigenvalue Problems: Open Questions from a Simons Workshop. With 35 co-authors (2026) [arXiv].
PhD Thesis: Pseudospectral Divide-and-Conquer for the Generalized Eigenvalue Problem. Supervised by Ioana Dumitriu (2024) [pdf].
Undergraduate Honors Thesis: Hecke Algebra Characters Evaluated at Kazhdan-Lusztig Basis Elements Give the Betti Numbers of Hessenberg Varieties. Supervised by John Shareshian (2018). Manuscript available upon request [abstract].

Page updated

Google Sites

Report abuse