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seanwevans/README.md

Sean W. Evans

I build experimental systems at the boundary of mathematics, high-performance computing, programming languages, databases, and machine learning.

Most of my projects begin with a structural question:

Can a different representation make this problem simpler, faster, safer, or possible at all?

The result is usually a working system: a compiler, accelerator, simulation, database runtime, file format, protocol, or deliberately strange proof of concept.

My background is in production software and ML engineering. I am increasingly focused on research-oriented computing: algorithms, numerical systems, GPU/FPGA acceleration, compilers, and unconventional computational models.

Gists are located here


Featured Work

A Lean 4 formalization program for 3-D Navier–Stokes regularity

PrimeTensor-NS is a Lean 4 / mathlib development aimed at the regularity question for the incompressible Navier–Stokes equations on ℝ³: the unforced, smooth-data form of the Clay Millennium problem.

It does not claim to solve that problem. The goal is to formalize as far toward the open frontier as possible, and then state that frontier as an explicit proposition in Lean instead of hiding it in an informal gap.

The development is built on its own foundation. Dimensions begin at one with no zeroth constructor, and magnitudes are assembled multiplicatively from prime factor chains before being bridged into mathlib's analysis.

Current results include:

  • exact physical Schwartz energy identities for H³ paths
  • conditional continuation criteria at a terminal time T
  • a proof that every fixed preterminal high-frequency dissipation tail vanishes, so any obstruction has to come from failure of uniformity as t → T
  • an equivalence between uniform tail vanishing and bounded canonical cutoff scales near T
  • a coercive-weight formulation needing no monotonicity or sign assumptions on the radial weight
  • neutral endpoint alternatives: smooth continuation, or a specific, named form of terminal frequency escape

Scale and rigor:

  • ~3,300 Lean modules, ~1.1M lines
  • ~15,000 theorems and lemmas
  • no sorry and no project axioms
  • CI-enforced audit of source coverage, theorem contracts, and axiom reports
  • prose LaTeX renderings of selected modules alongside the Lean source

The repository is explicit about what is not proved. It records where its criteria overlap with known results in the literature, which standard estimates still need formalizing, and why generic Hölder/Sobolev arguments cannot close the problem without genuinely new PDE structure.

The larger experiment is how far a machine-checked development can be pushed into an open problem while keeping an exact, auditable line between what is proved and what is assumed.


Exact FPGA acceleration for homomorphic encryption

An FPGA accelerator for OpenFHE BGVRNS ciphertext multiplication and BV relinearization on a PYNQ-Z2.

The project moves dense modular arithmetic and key-switch computation into RTL while preserving coefficient-exact compatibility with OpenFHE.

  • Exact hardware implementation of ciphertext multiplication and BV relinearization
  • Pipelined Barrett modular arithmetic
  • AXI DMA transport and coefficient-major evaluation-key reuse
  • Measured on physical PYNQ-Z2 hardware
  • 6,291,456 residue comparisons against OpenFHE with zero mismatches
  • 245.61 relinearized ciphertexts/sec in the current persistent-session design
  • 98.84% of the calculated input transport ceiling at the measured batch size

The repository documents not just the final implementation, but the sequence of architectural changes that moved the design from 91 to 245 ciphertexts/sec.


A systems language built around straight-line SIMD computation

Lockstep is an experimental data-oriented programming language for deterministic, high-throughput compute pipelines.

Instead of treating a program as a sequence of arbitrary instructions, Lockstep models computation as a static graph of data transformations.

It includes:

  • custom grammar and compiler frontend
  • semantic type checking
  • static memory topology
  • Struct-of-Arrays layout
  • explicit branchless compute kernels
  • linear reduction types
  • LLVM IR generation
  • manual SIMD lowering
  • generated C host interfaces
  • pipeline simulation
  • compiler diagnostics
  • benchmark regression testing
  • Language Server Protocol support

The experiment asks what a systems language looks like when predictable data movement and vector execution are architectural constraints rather than compiler afterthoughts.


CUDA numerical simulation laboratory

A collection of GPU-accelerated physical and mathematical simulations implemented primarily in CUDA.

Experiments include:

  • Smoothed Particle Hydrodynamics
  • hypersonic flow
  • reaction-diffusion systems
  • 3-D fluid dynamics
  • viscous Burgers flow
  • shallow-water equations
  • 2-D fluid solvers

The repository is a laboratory for numerical methods, GPU execution models, visualization, and the relationship between mathematical formulation and computational structure.


GPT-2 implemented entirely inside PostgreSQL

A complete GPT-2 implementation in which PostgreSQL acts simultaneously as the model store, tensor runtime, computational graph, optimizer state store, and execution environment.

The system includes:

  • native C tensor operations
  • reverse-mode automatic differentiation
  • relational autograd tape
  • GPT-2 attention and feed-forward layers
  • AdamW optimization
  • BPE tokenization
  • checkpointing
  • training and inference
  • SQL-driven text generation

Every model operation is represented through database state and transactions.

The larger experiment is whether a relational database can serve as a general computational runtime rather than merely storing inputs and outputs for one.


An experimental lossless representation for spatiotemporal data

4Splat explores an extension of indexed-color images into higher-dimensional image and video data.

Instead of treating every video frame independently, the format represents samples over spatial and temporal coordinates and indexes them through a shared palette of higher-dimensional splats.

The project includes:

  • a binary .4spl format
  • reference encoder and decoder
  • explicit binary layout and versioning
  • spatiotemporal indexing
  • Gaussian splat representation
  • lossless reconstruction

The broader question is whether representations normally associated with images can be generalized into useful structures over space-time.


Other Experiments

The rest of this account is my working laboratory.

It includes:

Programming languages & compilers branchless languages, safety-constrained languages, no-syntax-error languages, declarative ML languages, regular-expression engines, DSLs, interpreters, and unusual execution models.

Databases & runtimes PostgreSQL-native Git, shells, operating-system interfaces, browsers, ML runtimes, schema compilers, and other experiments in treating the database as a computational substrate.

GPU & parallel computing CUDA simulation, GPU databases, cellular automata, reinforcement-learning environments, cryptographic accelerators, and performance experiments.

Distributed systems consensus experiments, actor-style VMs, distributed ML execution, failover systems, and network-topology tools.

Low-level systems x86-64 assembly utilities, eBPF experiments, custom servers, binary formats, compression, PRNGs, and syscall-level tooling.

Mathematical experiments fractals, dynamical systems, cryptography, simulation, alternate computational representations, and small mathematical investigations.

Interesting Things games, civic software, weird interfaces, protocol tools, visualization experiments, and ideas that were worth implementing even when they had no obvious product attached.


What I Like Working On

I am particularly interested in problems where the obvious implementation is too slow, too complicated, or based on the wrong abstraction.

That usually means some combination of:

  • algorithms
  • scientific computing
  • high-performance computing
  • GPU and FPGA acceleration
  • compiler construction
  • programming-language design
  • numerical methods
  • database internals
  • distributed systems
  • machine-learning infrastructure
  • mathematical modeling
  • formal verification and theorem proving
  • unusual representations of computation

The recurring goal is to find the representation that makes the hard part easy.

Pinned Loading

  1. PrimeTensor-NS PrimeTensor-NS Public

    Machine-verified research program toward a global H³ bound for 3D Navier–Stokes

    Lean 1

  2. pynq_butterfly pynq_butterfly Public

    FPGA accelerator for exact OpenFHE DCRTPoly polynomial multiplication in Z_q[X]/(X^4096+1), on a PYNQ-Z2 (XC7Z020)

    SystemVerilog 2

  3. fluid-sims fluid-sims Public

    Collection of high-performance, CUDA-accelerated fluid dynamics and physics simulators, including SPH, hypersonic flow, and reaction-diffusion systems.

    Cuda 63 3

  4. 4splat 4splat Public

    Binary format and reference implementation for 4Splat (.4spl). Palette-based, lossless 4D video codec that generalizes indexed-color images to spatiotemporal data with Gaussian splats

    C 13 1

  5. lockstep lockstep Public

    Data-oriented systems programming language for high-throughput, deterministic compute pipelines, enforcing a straight-line SIMD execution model and static memory topology for maximum CPU vectorizat…

    Python 12

  6. pg_shell pg_shell Public

    Stateless, auditable, and replayable command shell built entirely on PostgreSQL and htmx. It replaces persistent shell processes with database-backed terminal sessions, where every command, output,…

    Python 7