Dual Numbers and Automatic Differentiation

This literate essay develops an implementation of a type called Differential. A Differential is a generalization of a type called a ["dual number"](https://en.wikipedia.org/wiki/Dual_number), and the glowing, pulsing core of the SICMUtils implementation of forward-mode automatic differentiation. »

Functional Numerical Methods

This page contains a literate-programming exported version a definite-integral package I built into SICMUtils [https://github.com/littleredcomputer/sicmutils], a Clojure(script) based computer algebra system based on Gerald Sussman's scmutils [https://groups.csail.mit.edu/mac/users/gjs/6946/refman.txt]. (Beware the buzzwords...) I expect that this post »

Power Series, Power Serious

This post spawned from work I've been doing on the SICMUtils [https://github.com/littleredcomputer/sicmutils] library; I've just released 0.13.0 [https://github.com/littleredcomputer/sicmutils/releases/tag/v0.13.0] and I hope you'll give it a try. SICMUtils is the engine behind the wonderful "Structure and »

How to Publish CLJSJS Jars to Clojars

I've been doing a lot of work in Clojurescript [https://github.com/littleredcomputer/sicmutils] lately, and the time finally came to pull in my first vanilla Javascript dependency [https://github.com/infusion/Complex.js/]. The default way to do this seems to be the CLJSJS project [http://cljsjs.github.io/ »

Optics and the Principle of Least Time

(This is a writeup of Exercise 1.3 [https://tgvaughan.github.io/sicm/chapter001.html#Exe_1-3] from Sussman and Wisdom's "Structure and Interpretation of Classical Mechanics". See the solutions repository [https://github.com/sritchie/sicm] for more.) * Law of Reflection * Geometry * Calculus * Law of Refraction * Calculus * Geometry The problem »

Half Angles from Euler's Formula

I've been reading the lovely Visual Complex Analysis [https://amzn.to/2UdJtv8] by Tristan Needham [https://www.usfca.edu/faculty/tristan-needham], and the visual-style proofs he's been throwing down have been wonderful and refreshing. I'll write more about this book and its goals later, but I was inspired this AM »

Niwot's Challenge 2018 Race Report

I feel like I'm never going to publish this damned thing... so here it is, in bullet point form. Maybe I'll tidy it up some day. Niwot's Challenge, a very fun race out in South Platte. Jason invited me to this damned thing last week... Text from Jason: "Free Sat? »

Niwot's Challenge 2019 Race Report

Well, I can honestly say, now, close to a year after the event, that I don't remember this event in the furious detail that characterizes my usual race reports. How lucky! We're not supposed to talk about the Niwot's Challenge [https://humanpotentialrunning.com/niwots-challenge/] at all. I ran this race »

Basis Changes for Linear Transformations

A 1-act sketch via Apple Pencil, for your viewing pleasure. Happy to link to further references or sketch this out in more detail — let me know in the comments if this is illuminating. Check it out below, or click here for a direct image link [https://samritchie.io/content/images/ »

Book: The Second Mountain

I had a hard time with this book; it showed up in the TED book club mailing months ago, and I went into my reading primed to love the message, which is concise and persuasive... but maybe so persuasive on its own that the book feels like 300 pages of »

Taylor Series and Imaginary Numbers

I wanted to share some of the intuition I've been developing around complex numbers [https://en.wikipedia.org/wiki/Complex_number]; some of the resources that have been helpful, for understanding why anyone would come up with an idea like $i$, the square root of -1, and then build an »

Entropy: Combinations and Permutations

In my ongoing quest to lay a more solid foundation for this new, strange life as a machine learning "researcher", I've been going through various foundational concepts and ideas and trying to build up rock solid intuitions that I can lean on for years. (Why the hell didn't I do »

Book: On Having No Head

What a strange, fantastic little book! I recently read Douglas Harding's "On Having No Head [https://amzn.to/2S27MKC]" after hearing Sam Harris mention the book in one of "Waking Up [https://share.wakingup.com/c6d08d5fe8f4]" meditations, and then many times on subsequent podcasts. The book is a long look »

Windshield and Windows Attached

The RV10 has windows! And a windshield! I've got everything attached and mostly cleaned up. Here's what it looks like now: I used three tubes of Lord 7545 A/E adhesive from Aerosport Products [http://www.aerosportproducts.com/product/lord-adhesive/], one for each pair of side windows and a full »

Spring Clips and Stage Time

I'm out here working on the plane today - I haven't made it out much, lately, but I'm in the garage spending the time. This project will end up taking roughly five years, three years longer than I thought it might when I started. I've gone through so many oscillations »