Introduction to

Presented by Diego Marinho de Oliveira

Short Version

Lead Data ScientistDate: 2016-08-25

Julia Language for Data Science, Machine Learning, Statistics, Mathematics

SummaryIntroduction

Interactive/Development Environments

Syntax

Libraries Highlights

Code Examples

Integration

Community

Important Events/Projects

IntroductionJulia is a high-level, high-performance dynamic programming language for technical computing

Adequate for Data Science, Research, Web application, scientific computer, among others

Multi-paradigm: multiple dispatch ("object-oriented"), procedural, functional, meta, multistaged

High-Performance JITCompiler

First appeared in 2012

Stable release 0.4.6 June 2016

Julia paper: http://arxiv.org/pdf/1411.1607v3.pdf

Introduction: Benchmarks

Source: http://julialang.org/benchmarks/

Introduction: How to Install JuliaInstall Julia version 0.4.6 (last stable version)

Windowshttps://s3.amazonaws.com/julialang/bin/winnt/x64/0.4/julia-0.4.6-win64.exe

Mac OS X

https://s3.amazonaws.com/julialang/bin/osx/x64/0.4/julia-0.4.6-osx10.7+.dmg

Ubuntusudo add-apt-repository ppa:staticfloat/juliareleasessudo add-apt-repository ppa:staticfloat/julia-depssudo apt-get updatesudo apt-get install julia

For more details check http://julialang.org/downloads/platform.html

Interaction/Development Environments

Julia Studio / Forio

Julia REPL

Kaggle Kernels

IJulia

JuliaBoxAtom

julia-vim

Syntax: Getting StartedJulia run code

Call Julia scriptjulia script.jl arg1 arg2…

Create a Julia command on the shelljulia -e 'for x in ARGS; println(X); end' foo bar

Create a Julia command using UTF-8 charactersecho 'println("Greetings! 你好 ! 안녕하세요 ?")' > ~/.juliarc.jl

Syntax: Variables

Example Variables

A variablex = 10

Float variabley = x + 2.0

UTF-8 variable 𝛔 = 1

Built-in Types

Int8, Int16, Int32, Int64, Int12, UInt32, UInt64, UInt128 103Bool false, trueAbstractString “Data!”Char ‘Z’Float16, Float32, Float64Complex 1 + 2imRational 5//6

Some math functions

round(Int, 76.0)

floor, ceil, trunc, eps, ...div, rem, mod, gcd, lcm, ...abs, sqrt, cbrt, exp, log, log2, ...sin, cos, tan, cot, sec, hypot, ...beta, gamma, eta, zeta, ...

Syntax: StringsTypes

AbstractStringUTF8StringASCIIStringChar

Simple Usage Examples

Using a chara = ‘A’

Simple stringb = ”for Data Science”

Interporlationprintln(”Julia is $b”)

Regular Expressionmatch(r”(\W\w+){,2}”, b)

Unicode usageprintln(“\u2200 x \u2203 y”)

Triple Quotejson = ”””{ “Id”: 10232}”””

Concat“Lets” * “ code”

Repeat sentencerepeat(“Julia”, 10)

Syntax: Functions, Control Flow Functions

Basic function definitionfunction f(x,y) x + yend

Terse function definitionf(x,y) = x+y

Optional and keywords argsx: optional; a: keywordf(x, y=1; a=3) = 1

Control Flow

Compound expressionsZ = begin f(x,y) x+ 1 x + yend

Repeated eval loopswhile x < 1for x=1:10

Short-circuit evaluation&&, ||

Conditional evaluationsIf x < 10 x += 1elseif 10 <= x < 12 x+= 2else x += 3end

Exception Handlingtry - catch

Tasks (coroutines)yieldto

Syntax: Types, Parallel and PackagesTypes

Abstract typeabstract Integer <: Real

Create a composite typetype Point

x::Float64y::Float64

end

Parallel

Execute parallel commandnheads = @parallel (+) for i=1:200000000 Int(rand(Bool))endPackages

Show statusPkg.status()

Install a new packagePkg.add(“<Package Name>”)

Remove PackagePkg.rm(“Package”)

Install from GitHubPkg.clone(“Package”)

Update packagesPkg.update()

Library Highlights● DataFrames.jl (data analysis)● Gadfly.jl (data visualization)● Vega.jl (data visualization)● HypothesisTests.jl (statistics)● XGBoost.jl (machine learning)● GLM.jl (machine learning)● Mocha.jl (machine learning/deep learning)● Low Rank Models.jl (machine learning)● JuMP.jl (optimization)

Code ExamplesSimple Example Preprocess and Plot Data

Import Packagesusing RDatasets,DataFrame, Gadfly

Load some datamtcars = dataset("datasets", "mtcars")

Filter Models by Horse Powermtcars = mtcars[mtcars[:HP] .> 100, :Model] Plotplot(mtcars, x=:Model, y=:HP, Geom.bar)

IntegrationsPython: PyCall

Use math from Pythonusing PyCall@pyimport mathmath.sin(math.pi / 4) - sin(pi / 4)

Use Python@pyimport matplotlib.pyplot as pltx = linspace(0,2*pi,1000); y = sin(3*x + 4*cos(2*x));plt.plot(x, y, color="red", linewidth=2.0, linestyle="--")plt.show()

IntegrationsR: RCall

Community

Lang

SStats Opt Parallel DB

Quantum

Astro

GPU FinanceSparse Math

...among others

Important Events/Projects