hellerbarde

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

MohamedAlaa

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

rgs

Falsehoods programmers believe about prices

1. You can store a price in a floating point variable.
2. All currencies are subdivided in 1/100th units (like US dollar/cents, euro/eurocents etc.).
3. All currencies are subdivided in decimal units (like dinar/fils)
4. All currencies currently in circulation are subdivided in decimal units. (to exclude shillings, pennies) (counter-example: MGA)
5. All currencies are subdivided. (counter-examples: KRW, COP, JPY... Or subdivisions can be deprecated.)
6. Prices can't have more precision than the smaller sub-unit of the currency. (e.g. gas prices)
7. For any currency you can have a price of 1. (ZWL)
8. Every country has its own currency. (EUR is the best example, but also Franc CFA, etc.)

jiffyclub

function condalist -d 'List conda environments.'
  for dir in (ls $HOME/miniconda3/envs)
    echo $dir
  end
end

function condactivate -d 'Activate a conda environment' -a cenv
  if test -z $cenv
    echo 'Usage: condactivate <env name>'
    return 1

codebrainz

Copyright 2015 Matthew Brush

Permission is hereby granted, free of charge, to any person obtaining a 
copy of this software and associated documentation files (the 
"Software"), to deal in the Software without restriction, including 
without limitation the rights to use, copy, modify, merge, publish, 
distribute, sublicense, and/or sell copies of the Software, and to 
permit persons to whom the Software is furnished to do so, subject to 
the following conditions:

erikbern

# Note – this is not a bash script (some of the steps require reboot)
# I named it .sh just so Github does correct syntax highlighting.
#
# This is also available as an AMI in us-east-1 (virginia): ami-cf5028a5
#
# The CUDA part is mostly based on this excellent blog post:
# http://tleyden.github.io/blog/2014/10/25/cuda-6-dot-5-on-aws-gpu-instance-running-ubuntu-14-dot-04/

# Install various packages
sudo apt-get update

Restuta

/*  Sometimes it's pretty easy to run ito troubles with React ES6 components.
    Consider the following code: */

class EventStub extends Component {
  componentDidMount() {
    window.addEventListener('resize', this.onResize.bind(this)); //notice .bind
  }
  
  componentWillUnmount() {
    window.removeEventListener('resize', this.onResize.bind(this));

sigma

{ pkgs ? import <nixpkgs> {} }:

with pkgs;
let

  su_exec = pkgs.stdenv.mkDerivation {
    name = "su-exec-0.2";
    src = fetchurl {
      url = https://github.com/ncopa/su-exec/archive/v0.2.tar.gz;
      sha256 = "09ayhm4w7ahvwk6wpjimvgv8lx89qx31znkywqmypkp6rpccnjpc";

cerisara

import sys

def getText(l):
    l=l.replace('\\citep','')
    l=l.replace('\\cite','')
    return l

with open(sys.argv[1],'rb') as f : ls = f.readlines()

empty=False

travisjeffery

Here's the simplest example showing how to do functional options in Golang.

They're a great way to enable users to set options and ease adding new options later.

package main

import (
	"flag"
	"fmt"