NL+SE Workshop talk at FSE 2016

1. Finding Similar Projects in GitHub using
Word2Vec and WMD
MD MASUDUR RAHMAN
DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF VIRGINIA
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2. Introduction
Given project details (description
and source code), the aim is to find
functionally similar projects
Finding functionally similar project
is important
Application/project recommendation
Code re-use, rapid prototyping
Discovering code plagiarism
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Code re-use Plagiarism checking
Application/project
Recommendation
How developer search for similar
projects?

3. General Purpose Search(Google)
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Query: android browser
Try to find application relevant to the query
Not intended to search for source code

4. GitHub Search: android browser
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Mostly keyword based search on textual
contents
Project name, description, etc.
Open and analyze jar, class, apk, etc.
Might rank irrelevant projects at the top
Less textual content
Use source code content
 Augment content by Method, Class, and API name

5. Model Workflow
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GitHub
Projects
Data Preprocessing
(per feature)
(Tokenization, Normalization,
Stemming, Stopwords
Removal, TF-IDF score based
word filtering)
Feature Extraction
(Description, Readme, Method
& Class Name, API Package
Name, API Class name)
Document Generation
(combined all features)
Search
Interface
Candidate
Project
Documents
Query Project
Documents
Document Similarity
Computation
(Word2Vec, WMD)
Search Result
(Ranked list of similar projects)
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6. Model Workflow
6
GitHub
Projects
Data Preprocessing
(per feature)
(Tokenization, Normalization,
Stemming, Stopwords
Removal, TF-IDF score based
word filtering)
Feature Extraction
(Description, Readme, Method
& Class Name, API Package
Name, API Class name)
Document Generation
(combined all features)
Search
Interface
Candidate
Project
Documents
Query Project
Documents
Document Similarity
Computation
(Word2Vec, WMD)
Search Result
(Ranked list of similar projects)
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7. How to measure document similarity?
Document 1: image gallery app for Lollipop
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Keyword based Cosine similarity
Bag of Word (BOW)
Document 2: android photo viewer
No common keyword!
Cosine similarity = 0
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8. How to measure document similarity?
Document 1: image gallery app for Lollipop
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Document 2: android photo viewer
Word Embedding
𝑤1
𝑤3𝑤2
𝑤4
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9. Word Embedding
“You shall know a word by the company it keeps” –J. R. Firth 1957
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Open source upgrade path for Odoo/OpenERP
Plugin to check for obvious upgrade points on the path to 3.0
Codes related to upgrade project
Demo app to demonstrate how to upgrade from Angular 1 to Angular 2
 Learn word vector for upgrade by its surrounding words
 Word2Vec
0.286
0.792
-0.171
-0.105
0.544
0.351
-0.653
0.274
upgrade
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10. Word2Vec
Input: Text corpus
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0.286
0.792
-0.171
-0.105
0.544
0.351
-0.653
0.274
upgrade
Word2Vec
Model
Word Embedding
Output: Word vectorsTraining

11. Word2Vec Model
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Document: image gallery app for android
Skip-gram
image
gallery
app
for
android

12. Example Word Embedding
In Embedded space
Similar meaning word clustered together
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image
photo
picture figure
sample
example
demo illustration
upgrade update
modify
change
install setup
launch
change
dimension size
height
length
range
Embedding for each word
How to get document/sentence level similarity?
 Word Mover’s Distance (WMD)

13. Word Mover’s Distance(WMD)
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image LollipopappgalleryD1
android viewerphotoD2
0.1
0.50.7

14. Word Mover’s Distance
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image LollipopappgalleryD1
android viewerphotoD2
0.1
0.50.7

15. Word Mover’s Distance
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image LollipopappgalleryD1
android viewerphotoD2
0.35
0.20.6

16. Word Mover’s Distance
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image LollipopappgalleryD1
android viewerphotoD2
0.35
0.150.2

17. Word Mover’s Distance
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image LollipopappgalleryD1
android viewerphotoD2
0.4
0.30.1

18. Word Mover’s Distance
Similarity Score(D1, D2) = 0.1 + 0.2 + 0.15 + 0.1 = 0.55
Smaller score means more similar
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image LollipopappgalleryD1
android viewerphotoD2
0.15
0.2
0.1
0.1

19. Preliminary Results
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Project Name Description Project Type
Query/
Rank
android_browser
Customize android webclient
(source code with readme file)
Lightning based
android browser
1 Myfacebook MyFacebook source code Lightning based
android browser
2 Speed-Browser-4G-Plus Speed Browser 4G Plus is based on Lightning Browser,
and licensed under the Mozilla Public License, v. 2.0..
Lightning based
android browser
3 Web-browser Web browser is based on Lightning Browser, and licensed
under the Mozilla Public License, v. 2.0..
Lightning based
android browser
4 JumpGo JumpGo Web Browser for Android JumpGo Android
Browser
5 VChrome Build an test browser for Viettel in job interview Android Browser
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20. Summary
We proposed a model for finding functionally similar projects in GitHub
Used textual and source code content to construct document
Measured similarity between document adopting Word Mover’s Distance
Leveraged Word2Vec word embedding
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21. Reference
Word2vec : Gensim python library
https://radimrehurek.com/gensim/models/word2vec.html
WMD
 https://github.com/mkusner/wmd
Wikipedia Dump.
https://dumps.wikimedia.org/enwiki/
GitHub Projects Data: The GHTorrent project
http://ghtorrent.org/
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22. Question?
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