joninvski

Two hours of ((((()))))

Today's topics:

• Part 1 - Boring basics
• Part 2 - Understanding the Parenthesis
• Part 3 - Playing with structures
• Part 4 - Functional transformation to sequences
• Part 5 - Software Transactional Memory
• Part 5.1 - Core.async
• Extra Part 6 - Data as code

mdouze

###########################################
# serialization of indexes to byte arrays
###########################################

def serialize_index(index):
    """ convert an index to a numpy uint8 array  """
    writer = faiss.VectorIOWriter()
    faiss.write_index(index, writer)
    return faiss.vector_to_array(writer.data)

jpgcc

What the heck is a Product Manager?

Track: Careers

Description

Product Manager: one of the least well-defined roles in the computer industry, although quite popular nowadays. No two companies have the same description for this job title, and it can even vary widely within one company. Are they the CEO of the product (bleargh!)? Are they project managers wearing sneakers and hipster glasses? What do they do all day? Is this a business, marketing or technology role? Is this someone with a degree in engineering, or an MBA? What can make a software engineer want to become a product manager?

sashaafm

% Example on how to get all Erlang formats from source code to disassembled bytecode
% Erlang Source --> Erlang AST --> Erlang Expanded AST --> Core Erlang --> BEAM Bytecode

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% First the original module
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-module(add).
-export([add/2]).

varyonic

# See https://codeship.com/documentation/docker/browser-testing/
FROM myapp:base

# We need wget to set up the PPA and xvfb to have a virtual screen and unzip to install the Chromedriver
RUN apt-get install -y wget xvfb unzip

# Set up the Chrome PPA
RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
RUN echo "deb http://dl.google.com/linux/chrome/deb/ stable main" >> /etc/apt/sources.list.d/google.list

protrolium

ffmpeg

Converting Audio into Different Formats / Sample Rates

Minimal example: transcode from MP3 to WMA:
ffmpeg -i input.mp3 output.wma

You can get the list of supported formats with:
ffmpeg -formats

You can get the list of installed codecs with:

sudara

# this monit config goes in /etc/monit/conf.d

check process puma_master
  with pidfile  /data/myapp/current/tmp/puma.pid
  start program = "/etc/monit/scripts/puma start"
  stop program = "/etc/monit/scripts/puma stop" 
  group myapp

check process puma_worker_0
  with pidfile /data/myapp/current/tmp/puma_worker_0.pid

piscisaureus

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 = git@github.com: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:

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

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD