An ag(e)ing hacker - posts tagged as "tutorial"

Languages and complexity, Part I: why I love Anki — 2024-01-02 19:47 Updated: 2024-08-21 12:01

August 2024 update: lack of endorsement This article used to endorse the services of a certain Russian language teacher and mention her by name, with permission. That person has now expressed the intention of making her course recordings “expire” trough some time limit which will make them unusable after a set date; the stated intent is motivating procrastinating students who hesitate too long before starting their study in earnest. Independently from the technical nature of their implementation and from whether the restrictions are possible to circumvent, anti-features are unacceptable and insulting. The teacher in question, now referred to here as [...] Read more

A practical GNU epsilon tutorial — 2013-08-23 12:54 Updated: 2023-09-29 17:57

A practical GNU epsilon tutorial Audience Lexical conventions Rationale and introduction My PhD thesis Implementation, and the relation beteen epsilon0 and epsilon1 The bootstrap problem Setup Writing more comfortably, from ‘guile+whatever’ and Emacs Basics of epsilon1 The stuff values are made of: fixnums, pointers, buffers Error situations in epsilon1 Slightly higher-level data structures: vectors, strings, boxes, tuples, records Equality and boxedness tags Lists, and simple programming examples Digression: a look at epsilon0 Practical programming in epsilon1 Sums A programming example: structural equality with boxedness tags A look at reflective data structures ‘e1:define’ is just a macro! S-expressions What’s the point [...] Read more

Happy pi approximation day 2013 — 2013-07-21 12:34 Updated: 2014-07-21 21:14

The fraction 22/7 has been known since antiquity as a simple rational approximation of pi. The fraction decimal expansion is 3.(142857); since pi is about 3.141592653589793, the approximation has three correct digits. Of course nowadays we can compute much better approximations with computers, and billions of digits are known: <http://en.wikipedia.org/wiki/Approximationsofπ> is a nice review also explaining some efficient computation methods. For example if you want to obtain a lot of pi digits in a short time you may like the series by Ramanujan, yielding very good approximations even with a small number of terms; but that’s not the point now. [...] Read more