Ali Ukani ali

Mathematics: What do grad students in math do all day?

A lot of math grad school is reading books and papers and trying to understand what's going on. The difficulty is that reading math is not like reading a mystery thriller, and it's not even like reading a history book or a New York Times article.

The main issue is that, by the time you get to the frontiers of math, the words to describe the concepts don't really exist yet. Communicating these ideas is a bit like trying to explain a vacuum cleaner to someone who has never seen one, except you're only allowed to use words that are four letters long or shorter.

What can you say?

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written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.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.

Locate the section for your github remote in the .git/config file. It looks like this:

[remote "origin"]
	fetch = +refs/heads/*:refs/remotes/origin/*
	url = [email protected]:joyent/node.git

Now add the line fetch = +refs/pull/*/head:refs/remotes/origin/pr/* to this section. Obviously, change the github url to match your project's URL. It ends up looking like this:

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

Some exercises from the Falsy Values workshops.

The good parts:

HTTP server and client in same script
Express cookies example
Express routing example
Express error handling
Express middlewares example
Simple HTTP proxy

	#!/usr/bin/env sh

	##
	# This is script with usefull tips taken from:
	# https://github.com/mathiasbynens/dotfiles/blob/master/.osx
	#
	# install it:
	# curl -sL https://raw.github.com/gist/2108403/hack.sh \| sh
	#

	From: Chris DeSalvo <[email protected]>
	Subject: Why we can't process Emoji anymore
	Date: Thu, 12 Jan 2012 18:49:20 -0800
	Message-Id: <[email protected]>

	--Apple-Mail=_6DEAA046-886A-4A03-8508-6FD077D18F8B
	Content-Transfer-Encoding: quoted-printable
	Content-Type: text/plain;
	charset=utf-8

	##########################################################
	# How to NEVER use Lambdas. An inneficient and yet educa-#
	# tonal guide to the proper misuse of the lambda constru-#
	# ct in Python 2.x. [DO NOT USE ANY OF THIS EVER] #
	# by: e000 (13/6/11) #
	##########################################################

	## Part 1. Basic LAMBDA Introduction ##
	# Well, it's worth diving straight into what lambdas are.
	# Lambdas are pretty much anonymous "one line" functions