Zurich Julia Users Group

Meetup 2 @Stamford Consultants – Meeting Room 2nd Floor26th June 2014

Agenda

• 18:00 – Arrival and warm-up• Pizzas / drinks

• 18:45 Pre-Session• Introduction / JuliaCon• A short overview of the performance of Julia compared to MATLAB and R

(Dominik)

• 19:30 Session 1 on general aspects - comparison with R, Python etc., and Julia's relation w.r.t. Data Science (Malcolm)• 20:30 Session 2 one on more specific topics such as Big Data, NoSQL

and parallelization (Malcolm)

JuliaCon – June 26 and27 in Chicago

http://juliacon.org/

The first-ever Julia conference will take place June 26 and 27 (Thursday and Friday) at the University of Chicago Gleacher Center in Chicago, Illinois. Expect two days of cutting-edge technical talks, a chance to rub shoulders with Julia's creators, and a weekend in a city known for its beautiful lakefront and world-class architecture.

Julia ResourcesThe Julia LanguageJulia (programming language) - Wikipedia, the free encyclopediaJulia Documentation — Julia Language 0.2.0 documentationThe Julia Manual — Julia Language 0.2.0 documentationThe Julia Standard Library — Julia Language 0.2.1 documentationAvailable Packages — Julia Language 0.2.0 documentationNoteworthy Differences from other Languages — Julia Language 0.2.1 documentationJulia DownloadsThe Julia BlogJulia PublicationsUsing Julia in the classroomJuliaCon 2014: June 26-27, Chicago, IL.juliabloggers.com - A Julia Language Blog AggregatorLearn julia in Y Minutesjulia-dev - Google Groupsjulia-users - Google Groups(99+) julia-stats – Google Groups(16) julia-opt – Google GroupsLesezeichen verwalten

Julia - PerformanceCompared to MATLAB, R , (and bit to Python)

Julia Compared to MATLAB, R (and Python)• Functions compared• Recursive Fibonacci• Parse Integer• Array Constructors• Smallest number divisiable by all numbers of a factorial• Numeric vector sort• Slow pi series• Slow pi series, vectorized• Random matrix statistics• Large random number generation and matrix multiplication

Win 7 Pro, 32 bit > 1 = slower than Julia< 1 = faster than JuliaTimings in seconds

Win 8.1,64 bit

Compared to PythonFun With Just-In-Time Compiling: Julia, Python, R and pqRhttp://www.juliabloggers.com/fun-with-just-in-time-compiling-julia-python-r-and-pqr/

function smallestdivisall(n::Int64) for i = 1:factorial(n) for j = 1:n if i % j !=0 break elseif j == n return i end end endend

def smallestdivisall(n): for i in xrange(1, math.factorial(n)+1): for j in xrange(1, n+1): if i % j != 0: break elif j == n: return i

Julia Python

This problem is calculating the smallest number that is divisible by all of the numbers in a factorial. For example, for the numbers in 5!, 60 is the smallest number that is divisible by 2, 3, 4 and 5.

Julia is about 3-6 x faster than Python

but…

… it is important to know of which

Python version we are talking about!

Julia Benchmark (Table)C performance = 1.0, smaller is better

Julia Benchmark (Chart)

@timeit – A quick Look at Macros# using the macro@timeit fib(25) "fib" "Recursive fibonacci"

# the macromacro timeit(ex,name,desc,group...) quote t = zeros(ntrials) for i=0:ntrials e = @elapsed $(esc(ex)) if i > 0 # warm up on first iteration t[i] = e end end @output_timings t $name $desc $group endend

macro output_timings(t,name,desc,group) quote (… hided code …) elseif print_output @printf "%s,%f\n" $name minimum($t) end gc() endend

1. The expression gets evaluated and the elapsed time is measured an stored in e

2. Skip the first measure because it is always sloweras Julia has to initialise the JIT first

1

2

Fast Numeric Computation with Julia

• Devectorize espressions – the opposite to MATLAB• Merge computations into a single loop• Write cache-friendly code• Avoid creating arrays in loops• Use BLAS• Use a 64 bit machine• Julia is faster on Linux and OSX than on Windows

Invitation: NLP++ Community

• NLP++• A programming language for Natural Language Processing• Based on C++• Much easier to learn and understand than C++

• VisualText: An NLP++ IDE• NLP++ Community (http://dev.nlpcloud.net/)• Growing the number of NLP++ developers• Sharing tips & tricks• Improve our analyzers

• If enough interest exists: New MeetUp Group for NLP++ in Zurich!

Start with Julia

Julia Binaries and IDEs

• Download and install the binaries• http://julialang.org/downloads/• Current stable version (May 2014): v0.2.1

• Choose an IDE (both are available for Linux/OSX/WIN)

• JuliaStudio by forio (the one I am using)

• http://forio.com/products/julia-studio/download /• Based on Qt

• LightTable• http://www.lighttable.com/• Based on the Clojure (JVM)• A very interesting approach, it’s worth to give it a try

Julia Docs

The Julia Manual: http://docs.julialang.org/en/release-0.2/manual/

The Julia Standard Library:http://docs.julialang.org/en/release-0.2/stdlib/

Available Packages:http://docs.julialang.org/en/release-0.2/packages/packagelist/

Julia Community

Google Groups• julia-users• julia-dev• julia-stats• julia-opt

Very friendly and no question is too basic .

We use GitHub to track our source code and for trackingand discussing issues and commits. There is also a list of packages for Julia, many of which are also hosted on and developed using GitHub.

Let’s Start with Julia

• Vectors, Matrices, Arrays• Simple Calculations• Functions• Devectorization• Types

http://learnxinyminutes.com/docs/julia/

Where does Julia come from?

The Creators of Julia

Jeff BezansonStefan Karpinski

Viral ShahAlan Edelman

MIT students and researchers

«Why we created Julia»

Interactive

Compiled

Keep hackers happyEasy to learn

Easy to install

Linux / OSX / WIN

Gluing programs together like in a shell

Linear Algebra like in MATLAB

String processing like Perl

Statistics like R

Mathematical notation like MATLAB

Macros like Lisp

Dynamism like Ruby

Speed of COpen Source

Liberal licence (MIT)

Some noteworthy features