B.Sc
Mathematics & Computer Science
Chhatrapati Shahu Ji Maharaj University (CSJM), Kanpur
GSoC '26 @ QC-Devs
Hi, I'm Aayush.
Scientific Python & C · quantum chemistry tooling
I'm a maths and CS student at CSJM University, Kanpur. I mostly work on the code that computes integrals for quantum chemistry. This summer I hooked the libcint library into GBasis and moved its slow loops into C.
353×faster integral loops
1,146tests in my GSoC PR
9+PRs merged in WoC 5.0
psst: move your mouse over the blue, or click to drop a new atom
Education
Cognitive Modelling Winter School
Run by Prof. Marieke van Vugt. My first real look at computational models of the mind.
Projects
Mostly open-source work on GBasis, plus one computer vision side project.
integral loop speedup vs. old Python path
Python1×
C loops353×
Same integrals, two engines. Press race.
libcint ↔ GBasis bindings
Replaced the old ctypes layer with a small C extension on the NumPy C-API, and moved the integral loops into C. Builds with scikit-build-core + CMake on Linux, macOS and Windows.
CPythonNumPy C-APICMake
# Obara–Saika recurrence
def vrr(a, m):
# [a+1| from [a| and [a-1|
return (PA*vrr(a, m)
+ WP*vrr(a, m+1)
+ ...)
Two-electron integral engine
Electron repulsion integrals for GBasis with the Obara–Saika and Head-Gordon–Pople recurrences.
Bowsensei
An archery coach that looks at an archer's form and gives feedback. Got recognised by a Google engineer.
In [1]:
import gbasis
S = overlap_integral(basis)
T = kinetic_energy(basis)
Out[1]: (n_bf, n_bf) arrays
Integrals tutorial notebook
Walks through overlap, kinetic and repulsion integrals with the new bindings, so new contributors don't have to start from the C code.
Work Experience
Google Summer of Code Contributor
QC-Devs · Better Linking Between Libcint and GBasis
- Moved the GBasis build to scikit-build-core and CMake.
- Wrote the NumPy C-API bridge (
libcint_wrap.c), generating the loop functions with token-pasting macros. - Rewrote the integral loops in C: 150–353× faster than the Python baseline, covered by 1,146 tests.
- Got library loading working on Linux, macOS and Windows; fixed dylib naming, ERI index order and the CINTOpt hookup.
- Presented to the group every two weeks, plus a final presentation and a lightning talk. Mentors: Michelle Richer, Marco Martínez, Prof. Paul Ayers.
Aayush was able to take our prototype Python/ctypes code and re-write it, comprehensively, into a proper Python C-extension module that sped up the code by (at least, in all cases) an order of magnitude.
"...ambitious, often going beyond what was asked, and showed good initiative when attempting things we weren't even sure would work (i.e. compiling on Windows)."
Open Source Contributor
Winter of Code 5.0 · GBasis
- Built the two-electron integral engine; 9+ PRs merged.
Open Source Contributor
Social Winter of Code
- Fixes and features for Smart Resume Reviewer and an AgriTech project.
Talks & Writing
Explaining the work matters as much as doing it.
GSoC 2026 Contributor Lightning Talk
My lightning talk on bringing libcint into GBasis: why the old ctypes path was slow, how the C extension works, and what it took to ship it on every OS. Recorded in three parts.
GSoC 2026 Final Report: Integrating libcint into GBasis
The full story of the project: pip-installable cross-platform builds, the C extension, and where the speedups came from.
Read the report →BowSensei: An AI-Powered Archery Coach
How three Gemini agents (intake, coach and planner) turn a photo or video of my shot into drills and a 7-day training plan.
Read on DEV →Skills
Languages
PythonC
Scientific computing
NumPyNumPy C-APIJupyterpytest
Build & tooling
CMakescikit-build-corecibuildwheelGit
Areas
Quantum chemistryPerformanceVertex AIAI agents