mnist-ai-up (Deep learning intro)

This project teaches you how to use machine learning to recognize handwriteen digits. Consider this the Hello World of AI.

I decided to use javascript and microservices to deploy this project, because it makes easy to run examples, without the need of deploying servers or learn a new programming language.

This network recognizes digits using a multilayer perceptron. I strongly recommend you to watch the videos bellow to understand the mathematical concepts behind this algorithm:

But what is a Neural Network? | Deep learning, chapter 1

Gradient descent, how neural networks learn | Deep learning, chapter 2

What is backpropagation and what is it actually doing? | Deep learning, chapter 3

Backpropagation calculus | Appendix to deep learning chapter 3

Details

I'm using Javascript and AWS lambda. The interface is based on this tutorial.

It uses Neataptic to train the network and AWS lambda to serve the API endpoint.

I decided to use Neataptic instea of Keras, because it opens the possibility to use Neuroevolution to evolve networks instead of human designed neural nets. I recommed this article to understand more about Neuroevolution:

Neuroevolution

Neuroevolution is increasingly getting better.

2017: The Year of Neuroevolution

A Visual Guide to Evolution Strategies

Simple NN evolution

Welcoming the Era of Deep Neuroevolution

Demo

Live demo

Setup

$ npm install

Train new model

$ node mnist-train.js

Deploy

Install Up

$ up

Notes

The build hook in up.json simply runs make, which ensures that the ./node-v8.4.0-linux-x64 binary is downloaded and present, Make is used so that this process only happens once.

{
  "hooks": {
    "build": "make"
  }
}

The proxy.command script is run inside Lambda to start your server. You can think of this as npm start, however you'd likely want npm start to be node app.js for local development. Defining proxy.command is strictly for running in production.

{
  "proxy": {
    "command": "./node-v8.7.0-linux-x64/bin/node app.js"
  }
}

Also note that ./node-v8.7.0-linux-x64 is placed in .gitignore so it's not checked into GIT. Up will ignore these by default, so we negate it with !node-v8.7.0-linux-x64 in .upignore.