Questions tagged [recommender-system]

Everything related to recommender systems

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4
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2answers
116 views

Evaluating recommendations quality and accuracy

I'm developing a recommendation system, that should provide my clients what actions they should take in order to hit certain targets. The underlying mechanics of the process is physical - where both ...
4
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1answer
111 views

Neural Network - Sparsity of collaborative based filtering and modelling the prediction problem

I'm fairly new to machine learning and for that matter, neural networks, but for the past couple of days I decided to take a stab at a fairly classical and practical problem of neural networks/machine ...
3
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0answers
51 views

What is the “matrix trick” in recommendation systems?

I just found slides from Matt Gormley (CMU) about recommendation systems. Under the heading "Unconstrained Matrix Factorization" he mentions: Optimization problem SGD SGD with Regularization ...
3
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1answer
347 views

Use of negative correlation coefficient in pearson correlation algorithm for recommender systems

I am new to recommender systems and am trying to find similar users of base users for user-based collaborative filtering. When I calculated the similarity score between two users (based on their ...
3
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0answers
103 views

Interpretation of Similarity Number generated by LogLikehood in Mahout

I have a pretty basic question and I was hoping someone could help me. I’m not a math person and I’m fairly new to mahout so I’m looking for a poor’s man explanation. It is a typical order ...
2
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0answers
26 views

Best way to evaluate interlaced recommendation system results while reducing bias

I already asked this question but I worded it in such a way that it was a completely different question to the one I want to ask. I have not deleted the old question in case someone finds it useful. ...
2
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1answer
580 views

precision@k and recall@k

Normally, I am familiar with precision and recall evaluation metrics but as you know recall@k and precision@k are different things and used in ranking evaluations especially recommendation systems. I ...
2
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0answers
63 views

Cross validation for Collaborative filter-based recommendation systems

I am an absolute beginner and am trying to implement collaborative filter for furniture ecommerce (think wayfair). I need some guidance about cross-validation strategy. Situation: I am working on a ...
2
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1answer
23 views

Reduce serving time complexity for real-time recommender systems

I am working on a real-time recommender system predicting a product to a user using deep learning techniques (like wide & deep learning, deep & cross-network etc). Product catalogue can be ...
2
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2answers
192 views

Which metrics for evaluating a recommender system with implicit data?

I am currently in the process of creating a recommender system. This recommender system works with a neural network and then searches for the closest neighbors and thus gives recommendations for a ...
2
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2answers
41 views

How to identify text similarity based on training data?

I have a set of documents (1 to 11) for which the labeling is done. Lets Assume: ...
2
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0answers
34 views

ML recommendation system with items organized in a tree

I would like to develop a recommendation system (probably hybrid, user-based and feature-based) for items which are organized in a tree (there are categories, divided in sub-categories, divided in sub-...
2
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0answers
614 views

How to create a model and make predictions with LightFM?

I've been researching on how to develop a hybrid recommender system for a simple book dataset, the main goal is to use both explicit data (purchases) and latent factors (features) to make the ...
2
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0answers
97 views

Multidimensional collaborative filtering model

I have a dataset that is approximately structured in the following way: 500 users, 500 products, 100 countries, 2 seasons, 300,000 ratings. Meaning that I have 300,000 rows containing unique ...
2
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0answers
26 views

Operations on Recommendation Embeddings

I've trained a recommendation system to recommend steam games based on game tags. An example output is shown below, where GAME is the game recommended based on the <...
2
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1answer
102 views

On the offline evalution of recommender system

There are mainly three ways to evaluate a recommender system: offline, online and user study. For most academic papers, offline evaluation is used to show the improvements: They split the offline ...
2
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1answer
72 views

Item-based recommender using K-NN

I'm trying to build an item-based recommender using k-nn. I have a list of items, all of which have some properties (features) in common. ...
2
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1answer
250 views

How to use testing data set to measure recommender system algorithm

I am new to recommender systems and am trying to build one using item-to-time CF. Currently, I am trying to evaluate/measure results using MAE. I have one step which is unclear (after I managed to ...
2
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0answers
198 views

Regularization term in Matrix Factorization

I'm trying to build a naive recommender system using latent factor model for MovieLens dataset. From the observed set of ratings I'm trying to build a model which will decompose the sparse matrix to N ...
2
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1answer
642 views

How do I perform Leave One Out Cross Validation For Top n Recommendation Sytems?

I am new in making recommendation systems . I am using the surpriselib library to evaluate my recommendations. All the Accuracy Metrics are well supported in this library. But I also want to compute ...
2
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1answer
438 views

Neural network model for sparse multi-class classifier on Tensorflow

The problem I'm trying to solve is the following: the data is Movielens with N_users=6041 and N_movies=3953, ~1 million ratings. For each user, a vector of size N_movies is defined, and the values ...
2
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0answers
247 views

SVD++ vs wALS: Which is the more effective for implicit feedback in Recommendation system

As SVD++ can be used for implicit feedback, I would like to know whether SVD++ can gives better results than the wALS algorithm (paper: Collaborative Filtering for Implicit Feedback Datasets ). I can'...
2
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2answers
90 views

How to recommend items after finding similar users in recommendation system

As the title explains my problem, I'm done with creating a recommendation system that can give me similar users for any given new user. The problem I face is, If I extract the list of products that ...
2
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0answers
45 views

What algorithm to choose order of university courses?

If I want to suggest a course path for a student who wanted to be a chemical engineering where each degree has to go through certain mandatory courses like math ,physics chemistry . Again to complete ...
2
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2answers
110 views

Matrix Factorisation Improvement

I am using SGD matrix factorisation (python) using the movielens dataset to make recommendations. I have a website which allows users to give feedback which is positive or negative to whether an item ...
2
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0answers
49 views

How does SVD actually provide the recommendations? I seem to get conflicting answers

I am reading a text book that basically says the following: Given a matrix A where A is USERS x ITEMS we can use SVD to decompose the matrix into: $$A = U \times \Sigma \times V^T$$ Then we can take ...
2
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0answers
318 views

Recommendation matrix as a product of User Similarity and Ratings

For both item-item and user-user collaborative filtering the recommendation matrix $Γ_{m x n}$, which is an (m x n) matrix, can be defined as: $$Γ(i,j)=r_{ij}$$ For user-user collaborative ...
2
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0answers
356 views

wrong prediction from graphlab.recommender.item_similarity_recommender

I have a question about basic understanding of how item-item collaborative filtering of "Graphlab" library works. I run this code: ...
2
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0answers
362 views

Taxonomy of recommender system methodologies

There's tons of material online but yet I can't reconcile the different definitions for recommender system methodologies / strategies. I think we can identify several axes: memory vs model based; ...
2
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0answers
1k views

How to use Python's FastFM library (factorization machines) for recommendation tasks?

I have a dataset of <user, item> pairs where each entry records which user bought which item. e.g. ...
2
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0answers
99 views

Selecting the number of hashes for minhash? Working with extremely sparse data and want more collisions

I'm attempting to use minhash to generate clusters and similarities, and I am primarily using ideas from these resources. http://www2007.org/papers/paper570.pdf https://chrisjmccormick.wordpress.com/...
2
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0answers
401 views

Spark ALS-WR giving the same recommended items for all users

We are trying to build a recommendation system for a supermarket with diverse item types (ranging from fast-moving grocery to low-moving electronic items). Some items are purchased more frequently in ...
2
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0answers
202 views

How to create Self learning data product

I am trying to build price recommendation solution for clients in a scalable manner. I have two choices as below. Professional service: Statistician involvement to build regression model or any ...
2
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0answers
323 views

Creating Data model for mahout recommendation engine

I am trying to build an item-item similarity matching recommendation engine with mahout. The data set is as in the following format ( attributes are in text not in numerals format ) ...
2
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0answers
46 views

Modeling Pipeline Budget

I have been tasked with creating a pipeline chart with the live data and the budgeted numbers. I know what probability of each phase of reaching the next. The problem is I have no Idea what to do ...
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0answers
11 views

Using Position as Feature in offline learn to rank

I have been wondering about a particular technique to denoise position bias in learn-to-rank.I am aware of inverse propensity weighting techniques. During a discussion, it was suggested to me , ...
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1answer
20 views

RecSys - Large dataset, few resources, how to sample?

I have been working with a RecSys model, for the first time, by experimenting with matrix factorization and matrix factorization with EmbedNN's. However, I am running into a memory problem since my ...
1
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0answers
26 views

Reommender system model Predicting the time watched duration for each user_id-video_id pair

I just want to ask If I can use Surprise Library (SVD algorithm) in building a recommender system that predicts the watch duration for a user_id and video_id pair? I have a dataset that contains the ...
1
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0answers
11 views

Recommendation System with ALS Implicit

I created a model for Recommending top 10 items to users similar to the approach used here https://github.com/benfred/implicit/blob/master/examples/lastfm.py I wanted to evaluate the model using NDCG ...
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0answers
12 views

is it better to use embedding with attributes in collaborative filtering or content-based approach?

I have a dataset with different text documents, a set of users who each read a different document, some historical info such as their reading speed, and other attributes related to the texts and users....
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0answers
20 views

Recommender System Approaches

I have a 4 datasets with user features, item features, user-item rating and User-item link data. I'm trying to build a recommender system to recommend top 10 items to the user by maximizing NDCG as ...
1
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0answers
18 views

How to get KNN linearly hybridised by two similarities?

I'm writing a KNN (collaborative filtering) hybrid similarity recommender and I need some advice. It is based on this paper. I've currently got 2 datasets. The first one is ...
1
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0answers
32 views

How does an autoencoder 'fill in the blanks' in the context of a recommender system?

My understanding is that an autoencoder takes an input, produces a lower dimensional representation of the input, which should explain the original features in the dataset, and then reconstructs the ...
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0answers
34 views

how to calculate the cosine similarity between two files?

I am using spark and scala to implement an issue. files contain phrases or sentences. I want to use domain based method to calculate the cosine similarity between tags.I convert two files into a ...
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0answers
28 views

How to use sklearn's Matrix factorization to predict new users' scores

I'm trying to use sklearn.decomposition.NMF to a matrix R that contains data on how users rated items to predict user ratings ...
1
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1answer
44 views

How to model a supervised recommender system with varying data

Suppose there are 2000 movies and a company wants to recommend some movies (for example, at most 5 movies) to each visitor. The objective is to learn how to predict which movie will be selected if a ...
1
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1answer
30 views

Scoring metric for recommendation system

I'm working on a project that involves building a news recommendation system. I've come as far as quantifying user interaction with different articles on the site into user's affinity towards atopic ...
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0answers
10 views

Predict the target audience for a new brand using data from other brands and customers buying behavior

Assume a company has a large database about wine, including brand, the taste of the wine, year, place of production, etc, and data of customers' purchase behavior. Now if there is a new brand coming ...
1
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1answer
240 views

Proper evaluation method for recommendation system with implicit feedback?

I am trying to implement a recommendation system for a live-streaming website. Here "users" are simply the website users and "items" are streamers that they should watch. I ...
1
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1answer
115 views

Click Through Rate calculation (CTR) calculation problem

So I'm doing a use case for a company interview and one of the questions is to calculate the CTR for a sorting algorithm. My question would be: Should I remove the operations where there were no ...