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Getting Lazy with Dataflow Graphs in Elixir

Intro

What do Tensorflow, Apache Airflow, Rule Engines, and Excel have in common?

Under the hood they all use DAGs to model data-flow dependencies of the program. Using graphs to model programs is great because you can modify the program at runtime. Lets talk about doing this in Elixir for great good.

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Each of these commands will run an ad hoc http static server in your current (or specified) directory, available at http://localhost:8000. Use this power wisely.

Discussion on reddit.

Python 2.x

$ python -m SimpleHTTPServer 8000

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// Numerical matrix examples

let x: Matrix = [[10, 9, 8], [3, 2, 1]]
let y: Matrix = [[1, 2, 3], [4, 5, 6]]
let z: Matrix = [[1, 2], [3, 4], [5, 6]]

x + y              // [[11, 11, 11], [7, 7, 7]]
x * y              // [[10, 18, 24], [12, 10, 6]]
2 * x              // [[20, 18, 16], [6, 4, 2]]
y ** z             // [[22, 28], [49, 64]]

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Import CustomElements from .html files

This is the technical implementation of the idea and concept described in my article “Why don’t we use HTML to author web components?”

Instead of using template literals, constructors and other specifics to define CustomElements, this is a proposal to just use standard HTML to define CustomElements.

The goal is to import CustomElements like this:

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(ns particles.core)

(def display (.getElementById js/document "display"))
(def context (.getContext display "2d"))
(def damping 0.999)
(def max-particles 250)
(def line-width 2)

(def app-state (atom {:width (.-innerWidth js/window)
                      :height (.-innerHeight js/window)}))

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A minimum setting to use browser REPL of ClojureScript

Assumed that you have set leiningen up and can use it.

1. Prepare files

Copy project.clj, repl-test.cljs and brepl-test.html from this gist or git clone this gist and move or copy repl-test.cljs under src directory.

$ git clone https://gist.github.com/6183122.git
$ cd 6183122/

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#!/usr/bin/env bash
local_json=$1
remote_ip=$2
remote_json=$3
remote_json_on_local=$(jupyter --runtime-dir)/remote.json

scp $remote_ip:$remote_json $remote_json_on_local
for socket_name in hb_port control_port stdin_port iopub_port shell_port; do
  local_port=$(sed 's/,/\n/g' $local_json | grep $socket_name | grep -o "[0-9]\+")
  remote_port=$(grep $socket_name $remote_json_on_local | grep -o "[0-9]\+")

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/*
We're going to start by adding a canvas to the page and getting a context for it.
*/
var canvas = document.createElement("canvas");
canvas.width = canvas.height = 320;
document.body.appendChild(canvas);
var gl = canvas.getContext("experimental-webgl");

/*
WebGL doesn't know how to draw anything onscreen out of the box. We have to

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            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                    Version 2, December 2004

 Copyright (C) 2011 YOUR_NAME_HERE <YOUR_URL_HERE>

 Everyone is permitted to copy and distribute verbatim or modified
 copies of this license document, and changing it is allowed as long
 as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE

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How to capture WebGL/Canvas by writing out PNGs to a sandboxed filesystem

Summary: Write .PNGs to the sandboxed file system in Chrome. Then sneak in and move them out.

1) Set up a sandboxed file system

// Request 40 GB (should be enough for ~5 minutes of 1080p)
var bytes = 1024*1024*1024*40;