Kendrick Tan kendricktan

This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.

You're Missing the Point of Promises

Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:

getTweetsFor("domenic", function (err, results) {
 // the rest of your code goes here.

Talks about Programming, Design, and Human Understanding

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A Tour of PyTorch Internals (Part I)

The fundamental unit in PyTorch is the Tensor. This post will serve as an overview for how we implement Tensors in PyTorch, such that the user can interact with it from the Python shell. In particular, we want to answer four main questions:

How does PyTorch extend the Python interpreter to define a Tensor type that can be manipulated from Python code?
How does PyTorch wrap the C libraries that actually define the Tensor's properties and methods?
How does PyTorch cwrap work to generate code for Tensor methods?
How does PyTorch's build system take all of these components to compile and generate a workable application?

Extending the Python Interpreter

PyTorch defines a new package torch. In this post we will consider the ._C module. This module is known as an "extension module" - a Python module written in C. Such modules allow us to define new built-in object types (e.g. the Tensor) and to call C/C++ functions.

	#!/usr/bin/env ruby
	require 'open-uri'
	require 'JSON'
	require 'digest/sha2'
	require 'pry'
	require 'bigdecimal'
	require 'bitcoin' # Because I need to cheat every now and then

	# Usage:
	# gem install pry json ffi ruby-bitcoin

	import re
	import hashlib
	import base58
	from pycoin.ecdsa import generator_secp256k1, public_pair_for_secret_exponent

	def bytetohex(byteStr):
	return ''.join( [ "%02X" % x for x in byteStr ] ).strip()

	litecoin = [b"\x30", b"\xb0"]
	bitcoin = [b"\x00", b"\x80"]

	# Required downloads:
	# NVIDIA-Linux-x86_64-367.27.run
	# cuda_8.0.27_linux.run
	# cudnn-8.0-linux-x64-v5.0-ga.tgz

	sudo apt-get install build-essential
	sudo apt-get install linux-image-extra-`uname -r`
	sudo ./NVIDIA-Linux-x86_64-367.27.run
	./cuda_8.0.27_linux.run --extract=`pwd`/extracts
	sudo ./extracts/cuda-linux64-rel-8.0.27-20733550.run

	#!/usr/bin/env python3
	# coding=utf-8
	import json

	from ansible.executor.task_queue_manager import TaskQueueManager
	from ansible.inventory import Inventory
	from ansible.inventory.group import Group
	from ansible.inventory.host import Host
	from ansible.parsing.dataloader import DataLoader
	from ansible.playbook.play import Play

	## bitwalletrecover.py - recover private keys from your darkcoin wallet
	## (this version was not tested with bitcoin/litecoin).
	## Requires python3, pycoin (https://pypi.python.org/pypi/pycoin),
	## and base58 (https://pypi.python.org/pypi/base58).
	##
	## Starting with Python 3.4, pip is included by default with the Python binary
	## installers. To install pip for older versions 3.x:
	##
	## sudo apt-get install python3-setuptools
	## sudo easy_install3 pip

	#!/bin/bash

	# install CUDA Toolkit v9.0
	# instructions from https://developer.nvidia.com/cuda-downloads (linux -> x86_64 -> Ubuntu -> 16.04 -> deb)
	CUDA_REPO_PKG="cuda-repo-ubuntu1604-9-0-local_9.0.176-1_amd64-deb"
	wget https://developer.nvidia.com/compute/cuda/9.0/Prod/local_installers/${CUDA_REPO_PKG}
	sudo dpkg -i ${CUDA_REPO_PKG}
	sudo apt-key adv --fetch-keys http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/7fa2af80.pub
	sudo apt-get update
	sudo apt-get -y install cuda-9-0

	// Copyright (c) 2018 HarryR
	// License: LGPL-3.0+

	pragma solidity ^0.5.0;

	/**
	* Implements MiMC-p/p over the altBN scalar field used by zkSNARKs
	*
	* See: https://eprint.iacr.org/2016/492.pdf
	*