Post on 25-Jun-2020
Apache MahoutFeb 13, 2012
Shannon Quinn
Cloud ComputingCS 15-319
MapReduce Review
C0 C1 C2 C3
M0 M1 M2 M3
IO0 IO1 IO2 IO3
R0 R1
FO0 FO1
chunks
mappers
Reducers
Map
Pha
seR
educ
e Ph
ase Shuffling Data
Scalable programming modelMap phaseShuffleReduce phaseMapReduceImplementations
GoogleHadoop Figure from lecture 6: MapReduce
MapReduce Review
C0 C1 C2 C3
M0 M1 M2 M3
IO0 IO1 IO2 IO3
R0 R1
FO0 FO1
chunks
mappers
Reducers
Map
Pha
seR
educ
e Ph
ase Shuffling Data
Scalable programming modelMap phaseShuffleReduce phaseMapReduceImplementations
GoogleHadoop Figure from lecture 6: MapReduce
This is our focus!
Apache Mahout
A scalable machine learning library
Apache Mahout
A scalable machine learning libraryBuilt on Hadoop
Apache Mahout
A scalable machine learning libraryBuilt on HadoopPhilosophy of Mahout (and Hadoop by proxy)
What does Mahout do?
Recommendation
Classification
Clustering
Other Mahout Algorithms
Dimensionality Reduction
Regression
Evolutionary Algorithms
Mahout
1. Recommendation
2. Classification
3. Clustering
Recommendation Overview
Help users find items they might like based on historical preferences
Recommendation Overview
Mathematically
Recommendation Overview
Alice
Bob
Peter
5 1 4
? 2 5
4 3 2 *based on example bySebastian Schelter
Recommendation Overview
5 1 4
- 2 5
4 3 2 *based on example bySebastian Schelter
Recommendation Overview
5 1 4
? 2 5
4 3 2
Bob
*based on example bySebastian Schelter
Recommendation Overview
5 1 4
1.5 2 5
4 3 2
Bob
*based on example bySebastian Schelter
Recommendation in Mahout
1st Map phase: process input
*based on example bySebastian Schelter
Recommendation in Mahout
1st Map phase: process input
1st Reduce phase: list by user
*based on example bySebastian Schelter
Recommendation in Mahout
2nd Map phase: Emit co-occurred ratings
*based on example bySebastian Schelter
Recommendation in Mahout
2nd Map phase: Emit co-occurred ratings
2nd Reduce phase: Compute similarities
*based on example bySebastian Schelter
Mahout
1. Recommendation
2. Classification
3. Clustering
Classification Overview
Assigning data to discrete categories
Classification Overview
Assigning data to discrete categoriesTrain a model on labeled data
Spam Not spam
Classification Overview
Assigning data to discrete categoriesTrain a model on labeled dataRun the model on new, unlabeled dataSpam Not spam
?
Naïve Bayes Example
Naïve Bayes Example
Prob (token | label) =
Naïve Bayes ExampleNot spam
Naïve Bayes Example
President Obama’s Nobel Prize Speech
Not spam
Naïve Bayes ExampleSpam
Naïve Bayes ExampleSpam
Spam email content
Naïve Bayes Example
Naïve Bayes Example
“Order a trial Adobe chicken dailyEAB-List new summer savings, welcome!”
Naïve Bayes in Mahout
Complex!
Naïve Bayes in Mahout
Complex!Training1. Read the features
Naïve Bayes in Mahout
Complex!Training1. Read the features2. Calculate per-document statistics
Naïve Bayes in Mahout
Complex!Training1. Read the features2. Calculate per-document statistics3. Normalize across categories
Naïve Bayes in Mahout
Complex!Training1. Read the features2. Calculate per-document statistics3. Normalize across categories4. Calculate normalizing factor of each label
Naïve Bayes in Mahout
Complex!Training1. Read the features2. Calculate per-document statistics3. Normalize across categories4. Calculate normalizing factor of each label
TestingClassification
Other Classification Algorithms
Stochastic Gradient Descent
Other Classification Algorithms
Stochastic Gradient DescentSupport Vector Machines
Other Classification Algorithms
Stochastic Gradient DescentSupport Vector MachinesRandom Forests
Mahout
1. Recommendation
2. Classification
3. Clustering
Clustering Overview
Grouping unstructured data
Clustering Overview
Grouping unstructured dataSmall intra-cluster distance
Clustering Overview
Grouping unstructured dataSmall intra-cluster distanceLarge inter-cluster distance
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
K-Means Clustering Example
Cats
Dogs
K-Means Clustering in Mahout
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C0 C1 C2 C3
M0 M1 M2 M3
IO0 IO1 IO2 IO3
R0 R1
FO0 FO1
chunks
mappers
Reducers
Map
Pha
seR
educ
e Ph
ase Shuffling Data
Figure from lecture 6: MapReduce
K-Means Clustering in Mahout
Assume: # clusters <<< # points
K-Means Clustering in Mahout
Assume: # clusters <<< # points
M0 M1 M2 M3
K-Means Clustering in Mahout
Assume: # clusters <<< # points
M0 M1 M2 M3
<clusterID, observation>
R0 R1
K-Means Clustering in Mahout
Map phase: assign cluster IDs
K-Means Clustering in Mahout
Map phase: assign cluster IDs
Reduce phase: reset centroids
K-Means Clustering in Mahout
Important notes--maxIter--convergenceDeltamethod
Other Clustering Algorithms
Latent Dirichlet AllocationTopic models
Other Clustering Algorithms
Latent Dirichlet AllocationTopic models
Fuzzy K-MeansPoints are assigned multiple clusters
Other Clustering Algorithms
Latent Dirichlet AllocationTopic models
Fuzzy K-MeansPoints are assigned multiple clusters
Canopy clusteringFast approximations of clusters
Other Clustering Algorithms
Latent Dirichlet AllocationTopic models
Fuzzy K-MeansPoints are assigned multiple clusters
Canopy clusteringFast approximations of clusters
Spectral clusteringTreat points as a graph
Other Clustering Algorithms
Latent Dirichlet AllocationTopic models
Fuzzy K-MeansPoints are assigned multiple clusters
Canopy clusteringFast approximations of clusters
Spectral clusteringTreat points as a graph
K-Means & Eigencuts
Mahout in Summary
Mahout in Summary
Scalable library
Mahout in Summary
Scalable libraryThree primary areas of focus
Mahout in Summary
Scalable libraryThree primary areas of focusOther algorithms
Mahout in Summary
Scalable libraryThree primary areas of focusOther algorithmsAll in your friendly neighborhood MapReduce
Mahout in Summary
Scalable libraryThree primary areas of focusOther algorithmsAll in your friendly neighborhood MapReducehttp://mahout.apache.org/
Thank you!