jsomers

Using websockets to easily build GUIs for Python programs

I recently built a small agent-based model using Python and wanted to visualize the model in action. But as much as Python is an ideal tool for scientific computation (numpy, scipy, matplotlib), it's not as good for dynamic visualization (pygame?).

You know what's a very mature and flexible tool for drawing graphics? The DOM! For simple graphics you can use HTML and CSS; for more complicated stuff you can use Canvas, SVG, or WebGL. There are countless frameworks, libraries, and tutorials to help you draw exactly what you need. In my case, this was the animation I wanted:

(Each row represents a "worker" in my model, and each rectangle represents a "task.")

fay59

Here's a list of mildly interesting things about the C language that I learned mostly by consuming Clang's ASTs. Although surprises are getting sparser, I might continue to update this document over time.

There are many more mildly interesting features of C++, but the language is literally known for being weird, whereas C is usually considered smaller and simpler, so this is (almost) only about C.

1. Combined type and variable/field declaration, inside a struct scope [https://godbolt.org/g/Rh94Go]

struct foo {
   struct bar {
 int x;

netgusto

module.exports = class Graph {

    constructor(V, E, directed = false) {
        this.vertices = V;
        this.edges = {};

        E.map(e => {
            const a = e[0]; const b = e[1]; const w = e[2] === undefined ? 1 : e[2];

            this.addEdge(a, b, w);

dadhi

using System;
using System.Collections.Generic;
using static System.Console;

namespace Union
{
    class Program
    {
        public static void Main()
        {

nadavrot

High-Performance Matrix Multiplication

This is a short post that explains how to write a high-performance matrix multiplication program on modern processors. In this tutorial I will use a single core of the Skylake-client CPU with AVX2, but the principles in this post also apply to other processors with different instruction sets (such as AVX512).

Intro

Matrix multiplication is a mathematical operation that defines the product of

exupero

I use my terminal as an IDE, largely thanks to Tmux. I spin up sessions for the API, the client front-end, and any other codebases I happen to be working in, as well as a session for tracking to do's and ideas.

I launch a session using a script I call zmux. If given a session name, zmux attaches to the session. If given a directory, zmux launches a new session and looks for a .tmuxrc file in the directory that it can source to set up the session, allowing me to easily spin up a workspace and daemon processes for a project. This is especially useful for projects I haven't touched in years.

I created a Tmux binding to switch between sessions on partial session name matches:

unbind t; bind t command-prompt -p "session" "run-shell \"find-tmux-session %%\""

fasiha

Well, that was unexpected. In the following, I’m trying to follow Jon Evans’ advice from “The Terrible Technical Interview”.

---

To: recruitment@EmployerABC.com
From: Ahmed Fasih
Subject: Re: Programming Test Invitation

Hi there! Thanks for offering to let me take a HackerRank test for ABC, I appreciate the vote of confidence.

enricofoltran

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"

bhb

Building a blockchain, assisted by Clojure spec

In an effort to gain at least a superficial understanding of the technical implementation of cryptocurrencies, I recently worked my way through "Learn Blockchains by Building One" using Clojure.

This was a good chance to experiment with using spec in new ways. At work, we primarily use spec to validate our global re-frame state and to validate data at system boundaries. For this project, I experimented with using instrumentation much more pervasively than I had done elsewhere.

This is not a guide to spec (there are already many excellent resources for this). Rather, it's an experience report exploring what went well, what is still missing, and quite a few unanswered questions for future research. If you have solutions for any of the problems I've presented, please let me know!

You don't need to know or care about blockchains to understand the code be

BusFactor1Inc

;;
;; scheme coin - a common lisp blockchain
;;
;; Burton Samograd
;; 2017

(load "~/quicklisp/setup.lisp")

(defconstant *coin-name* "Scheme Coin")