mlliarm

Installing Python 3.7 from source on Ubuntu 18.04

# update system
sudo apt update && sudo apt upgrade -y

# install build tools and python prerequisites
sudo apt install build-essential libssl-dev zlib1g-dev libncurses5-dev libncursesw5-dev libreadline-dev libsqlite3-dev libgdbm-dev libdb5.3-dev libbz2-dev libexpat1-dev liblzma-dev tk-dev libffi-dev

# download and extract python

mlliarm

Gists

In reverse chronological order from gist creation:

• 2022-04-18: Multiple keyboard layouts on RaspberryOS 64 bit, Debian Bullseye.
• 2022-02-28: Youtube from the Linux CLI.
• 2022-02-26: How to use RSS to get updates from Twitter hashtags.
• 2022-02-25: Factoring 10...01.
• 2021-12-23: An oldtimer's APL Code (tradfn v., dfn v.).
• 2021-12-22: Testing SymPy.

mlliarm

// Link to the original: http://www.jsoftware.com/jwiki/Essays/Incunabulum
// Found at https://news.ycombinator.com/item?id=8533843

typedef char C;

typedef long I;

typedef struct a {
  I t,r,d[3],p[2];
}* A;

mlliarm

Below are the Big O performance of common functions of different Java Collections.


List                 | Add  | Remove | Get  | Contains | Next | Data Structure
---------------------|------|--------|------|----------|------|---------------
ArrayList            | O(1) |  O(n)  | O(1) |   O(n)   | O(1) | Array
LinkedList           | O(1) |  O(1)  | O(n) |   O(n)   | O(1) | Linked List
CopyOnWriteArrayList | O(n) |  O(n)  | O(1) |   O(n)   | O(1) | Array

mlliarm

-- Authors: Mike Spivey and Silvija Seres
-- Taken from: https://www.cs.ox.ac.uk/publications/books/fop/dist/fop/chapters/9/Logic.hs,
-- "The fun of programming book", https://www.cs.ox.ac.uk/publications/books/fop/,
-- Chapter 9, Combinators for logic programming
-- Haskell 98 compliant.

module Logic where
import List

-- Section 9.2

mlliarm

Testing SymPy

What

I've been a great fan of Mathematica since the first time I've used it back in 2000.

After a couple discussions of one of the creators of SymPy over Twitter, I decided to look deeper in this interesting project.

Tests

This is the Python version:

mlliarm

// Based on the article 'Combinators for logic programming' by Michael Spivey and Silvija Seres.
// Original author's blog post: http://ademar.name/blog/2011/06/combinators-for-logic-programm.html
// More info about this language: https://en.wikipedia.org/wiki/F_Sharp_(programming_language)

let rec inf_seq n =  seq { yield n; yield! inf_seq (n+1) }

let rec lzw f l1 l2 =
    LazyList.delayed ( fun () -> 
    match l1,l2 with
    |LazyList.Nil, _ -> l2

mlliarm

An oldtimer's APL code

What

Some pretty cool code from the 70s'-80s' that a Reddit user shared at this question.

Here's what u/snarkuzoid wrote:

5x5 Knight's Tour in APL

It puts an A in the middle, then randomly does a knight's tour,

mlliarm

Problem

A lot of GitHub projects need to have pretty math formulas in READMEs, wikis or other markdown pages. The desired approach would be to just write inline LaTeX-style formulas like this:

$e^{i \pi} = -1$

Unfortunately, GitHub does not support inline formulas. The issue is tracked here.

Investigation

mlliarm

Rational Approximation of pi

What

Sometime ago, a user of r/math posted this outreageous result and claimed that this fraction approximates pi.

I confirmed this result of his, using J and using PARI/GP.

But today, I was reading the lemma on tacit programming over aplwiki.com and saw this amazing result: