for Fun and Profit
Why
-
Strong Community
Incredibly Fast
Expressive and Terse Type System
Easy to transition from R
But first…
Let’s walk through a machine installation.
Windows Machine Installation
http://julialang.org/downloads/
Ubuntu Installation
’s
Creators and Community
The Fab Four
• A grad student with a great idea
• An wisened industry heavy hitter
• A mathematics professor
• A physical sciences researcher
Jeff Bezanson
• Recent PhD, MIT
• Thesis: “Abstractions in Technical
Computing”
• Translation: “Julia, My New Lang”
Stefan Karpinski
• Language Co-Creator
• Industry Heavy-Hitter
• Work Experience
• Akamai
• Citrix Online
• Etsy
Alan Edelman
• Professor of Applied Mathematics, MIT
• Jeff’s thesis advisor
• Specializes in “Random Matrix Theory”
• Julia’s Linear Algebra libraries bear his mark
Viral Shah
• PhD Computer Science
• Co-inventor of Julia
• Researcher in Biological / Physical Sciences
It’s all open source!
(and very active)
(and interactive)
Next Topic: Language Speed
• We’ll evaluate the claim that “Julia is Fast”
• Particularly in comparison to R
Speed Case Study – Conditional Probability
• You are a Commodity Trader
• Let’s say you know that a certain fruit will be profitable
• Given that fruit is profitable, what is the probability some other fruit
will be profitable?
• Example:
• “I know Apples will be profitable tomorrow. Historically, Bananas are
profitable 90% of the days that Apples are profitable. Therefore, I will also
trade Bananas.”
Input Data
Fruits
Historical Days
Input Data
Fruits
Days
March 5th, 2012
Desired Output
Fruits
Fruits
P(Guava|Bananas) = 0.325
Julia Implementation (No BLAS)
Julia Implementation (BLAS)
R Implementation
Benchmarked Comparison
Published Benchmarks:
http://julialang.org/
http://julialang.org/benchmarks/
Next Topic: Type System
Type System Features Comparison
Julia
C++
Java
C#
Python
Dynamic Typing
X
X
Static Typing
X
X
X
X
Abstract Types
X
X
X
X
Parametric Types
X
X
X
X
X
X
Covariance /
Contravariance
Multiple
Inheritance
Union Types
X
X
Totals
6
X
X
X
X
X
X
X
X
Haskell
X
X
Tuples
Interfaces / Traits
/ Contracts
X
R
X
X
X
X
X
X
7
5
6
X
4
2
6
How to evaluate a Type System?
• Terseness
• Case Study: Generic Binary Trees
• Languages Compared: Julia vs. C#
• Expressiveness
• Case Study: SKI Combinator Calculus
• Languages Compared: Haskell vs. Julia vs. C#
Type System Case Study: Terseness
• Problem Space: OOP
• Generic Binary Trees
• Julia vs. C#
• Criteria: Which can be done in less lines of code?
C# Implementation
Total: 32 lines of code
Julia Implementation
Total: 10 lines of code
Type System Case Study 2: Expressiveness
• Problem Space: Logic / Computer Science
• The SKI Combinators are an alternative basis for computation, like the lambda calculus
• Julia vs. Haskell
• Criteria: Can it even be done?
• If you’re interested:
Julia Implementation
Haskell Implementation
I’m an R guy.
Will I be comfortable with Julia?
Which one is R?

Thank you!
kyle.pena@nlplogix.com
https://github.com/kyle-pena-nlp
Time Permitting
https://www.juliabox.org/
Language Basics
• Control Flow
• Functions
• Types
• Parametric Types (Generics)
Control Flow – If/ElseIf
Control Flow – For Loop
Control Flow – While Loop
Control Flow – Try/Catch
Composite Types
Parametric aka Generic Types
C# Equivalent: