Latest posts
- Notes on Lagrange Interpolating PolynomialsMar 01, 2026Eli Bendersky
Polynomial interpolation is a method of finding a polynomial function that fits a given set of data perfectly. More concretely, suppose we have a set of n+1 distinct points [1]: \[(x_0,y_0), (x_1, y_1), (x_2, y_2)\cdots(x_n, y_n)\] And we want to find the polynomial coefficients {a_0\cdots a_n} such that: \[p(x)=a_0 + a_1 x + a_2 x^2 + \cdots + a_n x^n\] Fits all our points; that is p(x_0)=y_0, p(
- Notes on Linear Algebra for PolynomialsFeb 26, 2026Eli Bendersky
We’ll be working with the set P_n(\mathbb{R}), real polynomials of degree \leq n. Such polynomials can be expressed using n+1 scalar coefficients a_i as follows: \[p(x)=a_0+a_1 x + a_2 x^2 + \cdots + a_n x^n\] Vector space The set P_n(\mathbb{R}), along with addition of polynomials and scalar multiplication form a vector space. As a proof, let’s review how the vector space axioms are satisfied. W
- Rewriting pycparser with the help of an LLMFeb 05, 2026Eli Bendersky
pycparser is my most widely used open source project (with ~20M daily downloads from PyPI [1]). It's a pure-Python parser for the C programming language, producing ASTs inspired by Python's own. Until very recently, it's been using PLY: Python Lex-Yacc for the core parsing. In this post, I'll describe how I collaborated with an LLM coding agent (Codex) to help me rewrite pycparser to use a hand-wr
- Compiling Scheme to WebAssemblyJan 17, 2026Eli Bendersky
One of my oldest open-source projects - Bob - has celebrated 15 a couple of months ago. Bob is a suite of implementations of the Scheme programming language in Python, including an interpreter, a compiler and a VM. Back then I was doing some hacking on CPython internals and was very curious about how CPython-like bytecode VMs work; Bob was an experiment to find out, by implementing one from scratc
- Summary of reading: October - December 2025Jan 01, 2026Eli Bendersky
"The Origins of Political Order: From Prehuman Times to the French Revolution" by Francis Fukuyama - while reading this book it occurred to me that domains of study like political sciense must be incredibly difficult and frustrating. Imagine trying to match a model onto a set of data; the model has thousands of parameters, but you only have dozens or a couple of hundred of data points. This is wha