1. 9/5 |
Tue |
Course overview. Probability review. Linearity of expectation. |
Slides. Compressed slides. Reading: MIT short videos and exercises on probability (go to Unit 4). Khan academy probability lessons (a bit more basic). Chapters 1-3 of Probability and Computing with content and excersises on basic probabiliy, expectation, variance, and concentration bounds. |
Randomized Methods, Sketching & Streaming |
2. 9/7 |
Thu |
Estimating set size by counting duplicates. Markov's inequality. Random hashing for efficient lookup. Collision-free hashing. |
Slides. Compressed slides. Reading: Chapters 1-3 of Probability and Computing with content and excersises on basic probabiliy, expectation, variance, and concentration bounds. |
3. 9/12 |
Tue |
More random hashing: 2-level hashing. 2-universal and pairwise independent hashing. |
Slides. Compressed slides. Reading: Chapter 2.2 of Foundations of Data Science with content on Markov's inequality and Chebyshev's inequality. Exercises 2.1-2.6. Chapters 1-3 of Probability and Computing with content and excersises on basic probabiliy, expectation, variance, and concentration bounds. Some notes (Arora and Kothari at Princeton) proving that the ax+b mod p hash function described in class in 2-universal.
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4. 9/14 |
Thu |
Hashing for load balancing. Chebyshev's inequality. The union bound. |
Slides. Compressed slides. Reading: Chapter 2.2 of Foundations of Data Science with content on Markov's inequality and Chebyshev's inequality. Exercises 2.1-2.6. Chapters 1-3 of Probability and Computing with content and excersises on basic probabiliy, expectation, variance, and concentration bounds.
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5. 9/19 |
Tue |
Exponential concentration bounds and the central limit theorem. |
Slides. Compressed slides. Reading: Chapter 4 of Probability and Computing on exponential concentration bounds. Some notes (Goemans at MIT) showing how to prove exponential tail bounds using the moment generating function + Markov's inequality approach discussed in class. |
6. 9/21 |
Thu |
Finish up exponential concentration bounds. Bloom Filters. |
Slides. Compressed slides. Reading: Chapter 4 of Probability and Computing on exponential concentration bounds. Chapter 4 of Mining of Massive Datasets, with content on bloom filters. See here for some explaination of why a version of a Bloom filter with no false negatives cannot be achieved without using a lot of space. See Wikipedia for a discussion of the many bloom filter variants, including counting Bloom filters, and Bloom filters with deletions. See Wikipedia again and these notes for an explaination of Cuckoo Hashing, a randomized hash table scheme which, like 2-level hashing, has O(1) query time, but also has expected O(1) insertion time. |
7. 9/26 |
Tue |
Finish up Bloom filter analysis. |
Slides. Compressed slides. Reading: Chapter 4 of Mining of Massive Datasets, with content on bloom filters. See here for full Bloom filter analysis. |
8. 9/28 |
Thu |
Min-Hashing for Distinct Elements. The median trick. |
Slides. Compressed slides. Reading: Chapter 4 of Mining of Massive Datasets, with content on distinct elements counting.
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9. 10/3 |
Tue |
Distinct elements in pratice: Flajolet-Martin and HyperLogLog. Start on Jaccard similarity and motivation for the fast similarity search problem. |
Slides. Compressed slides. Reading: The 2007 paper introducing the popular HyperLogLog distinct elements algorithm. Chapter 3 of Mining of Massive Datasets, with content on Jaccard similarity, MinHash, and locality sensitive hashing.
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10. 10/5 |
Thu |
Fast similarity search via locality sensitive hashing. MinHashing for Jaccard similarity. |
Slides. Compressed slides. Reading: Chapter 3 of Mining of Massive Datasets, with content on Jaccard similarity, MinHash, and locality sensitive hashing.
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10/10 |
Tue |
No Class. Monday class schedule followed. |
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11. 10/12 |
Thu |
Frequent elements estimation via Count-min sketch.
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Slides. Compressed slides. Reading: Notes (Amit Chakrabarti at Dartmouth) on streaming algorithms. See Chapters 2 and 4 for frequent elements. Some more notes on the frequent elements problem. A website with lots of resources, implementations, and example applications of count-min sketch. Linear Algebra Review: Khan academy. |
12. 10/17 |
Tue |
Dimensionality reduction, low-distortion embeddings, and the Johnson Lindenstrauss Lemma.
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Slides. Compressed slides. Reading: Chapter 2.7 of Foundations of Data Science on the Johnson-Lindenstrauss lemma. Notes on the JL-Lemma (Anupam Gupta (CMU). Sparse random projections which can be multiplied by more quickly. |
13. 10/19 |
Thu |
Midterm Review. |
Slides. |
10/24 |
Tue |
Midterm (In Class) |
Study guide and review questions. |
Spectral Methods |
14. 10/26 |
Thu |
Finish up the JL Lemma proof. Example application to clustering. |
Slides. Compressed slides. Reading: Chapter 2.7 of Foundations of Data Science on the Johnson-Lindenstrauss lemma. Notes on the JL-Lemma (Anupam Gupta (CMU). |
15. 10/31 |
Tue |
Intro to principal component analysis, low-rank approximation, data-dependent dimensionality reduction. Orthogonal bases and projection matrices. |
Slides. Compressed slides.
Reading: Chapter 3 of Foundations of Data Science and Chapter 11 of Mining of Massive Datasets on low-rank approximation and the SVD. Some good videos for linear algebra review. Some other good videos overviewing the SVD and related topics (like orthogonal projection and low-rank approximation). |
16. 11/02 |
Thu |
Dual column/row view of low-rank approximation. Best fit subspaces and optimal low-rank approximation via eigendecomposition. |
Slides. Compressed slides. Reading: Proof that optimal low-rank approximation can be found greedily (see Section 1.1). Chapter 3 of Foundations of Data Science and Chapter 11 of Mining of Massive Datasets on low-rank approximation. |
17. 11/07 |
Tue |
Finish up optimal low-rank approximation via eigendecomposition. Eigenvalues as a measure of low-rank approximation error.
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Slides. Compressed slides.
Reading: Chapter 3 of Foundations of Data Science and Chapter 11 of Mining of Massive Datasets on low-rank approximation. |
18. 11/09 |
Thu |
The singular value decomposition and connections to low-rank approximation. Applications of low-rank approximation beyond compression. Matrix completion and entity embeddings.
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Slides. Compressed slides.
Reading: Notes on SVD and its connection to eigendecomposition/PCA (Roughgarden and Valiant at Stanford). Notes on matrix completion, with proof of recovery under incoherence assumptions (Jelani Nelson at Harvard). Levy Goldberg paper on word embeddings as implicit low-rank approximation. |
19. 11/14 |
Tue |
Spectral graph theory and spectral clustering. |
Slides. Compressed slides. Reading: Chapter 10.4 of Mining of Massive Datasets on spectral graph partitioning. For a lot more interesting material on spectral graph methods see Dan Spielman's lecture notes. Great notes on spectral graph methods (Roughgarden and Valiant at Stanford). |
20. 11/16 |
Thu |
The stochastic block model. |
Slides. Compressed slides. Reading: Dan Spielman's lecture notes on stochastic block model, including matrix concentration + David-Kahan perturbation analysis.. Further stochastic block model notes (Alessandro Rinaldo at CMU). A survey of the vast literature on the stochastic block model, beyond the spectral methods discussed in class (Emmanuel Abbe at Princeton). |
21. 11/21 |
Tue |
Computing the SVD: power method. Krylov methods. Bonus material: connection to random walks and Markov chains. |
Slides. Compressed slides. Reading: Chapter 3.7 of Foundations of Data Science on the power method for SVD. Some notes on the power method. (Roughgarden and Valiant at Stanford). |
11/23 |
Thu |
No Class. Thanksgiving recess. |
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11/28 |
Tue |
No Class. Professor traveling. |
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Optimization |
22. 11/30 |
Thu |
Start on optimization and gradient descent. |
Slides. Compressed slides. Reading: Chapters I and III of these notes (Hardt at Berkeley). Multivariable calc review, e.g., through: Khan academy |
23. 12/05 |
Tue |
Gradient descent analysis for convex Lipschitz functions. |
Slides. Compressed slides. Reading: Chapters I and III of these notes (Hardt at Berkeley). |
24. 12/07 |
Thu |
Constrained optimization and projected gradient descent. Course conclusion/review. |
Slides. Compressed slides. |
12/14, 10:30am - 12:30pm |
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Final Exam. |
Study guide and review questions. |