Recommender Systems

Collaborative filtering, content-based retrieval and the two-stage system they become.

Module 02.8 · Intermediate
Free

7h · 9 lessons · 0 challenges

Before this: Unsupervised Learning & Anomaly Detection

About this module

Recommenders are the most widely deployed machine learning there is, and they are built from a factorization you can derive. This module starts at the rating matrix, derives collaborative filtering from its cost, then handles the two awkward realities: implicit feedback and users with no history.

Then content-based filtering and the two-tower retrieval that scales it, which is the architecture behind most feeds you use.

After this module you can

9 lessons

Lesson 1
1Making recommendations, and the rating matrix
Kind
Concept
Length
45 min
Lesson 2
2Collaborative filtering and its cost function
Kind
Concept
Length
50 min
Lesson 3
3Binary labels, implicit feedback and mean normalization
Kind
Concept
Length
45 min
Lesson 4
4Content-based filtering and the two-tower idea
Kind
Concept
Length
50 min
Lesson 5
5Retrieval and ranking at scale
Kind
Concept
Length
45 min
Lesson 6
6Cold start and the exploration problem
Kind
Concept
Length
40 min
Lesson 7
7PCA for visualizing what the model learned
Kind
Concept
Length
40 min
Lesson 8
8Build a two-stage recommender end to end
Kind
Lab
Length
90 min
Lesson 9
9Checkpoint: design the recommender
Kind
Checkpoint
Length
25 min

The challenge: Cold Start

A new user with three clicks. Recommend the fourth, and explain what your system is betting on.

Worth 350 XP.

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