Collect and clean interaction data
Aggregate user–item interactions (views, clicks, purchases) into a timestamped table and filter or anonymise personally identifiable fields.
Neural collaborative filtering models. Compare predicted item preferences.
Neural collaborative filtering models user–item interactions with neural networks that learn latent representations and interaction functions. Important modelling choices include representation size, interaction architecture (MLP vs. dot product), negative sampling, and ranking metrics such as HR@k or NDCG.
Learning concept · Not a validated service
Neural collaborative filtering models user–item interactions with neural networks that learn latent representations and interaction functions. Important modelling choices include representation size, interaction architecture (MLP vs. dot product), negative sampling, and ranking metrics such as HR@k or NDCG.
A proposed application is a personalised product recommender that proposes a short ranked list for logged-in users; in practice a human-driven business rule layer should moderate suggestions and a logging pipeline must capture feedback before any production rollout.
Aggregate user–item interactions (views, clicks, purchases) into a timestamped table and filter or anonymise personally identifiable fields.
Define user and item embeddings, combine them with an interaction MLP or dot-product head, and train with a ranking-aware loss and negative sampling.
Use metrics such as Hit Rate@K, NDCG@K or MAP on a temporally-split test set and inspect per-segment performance for cold users and popular items.
Implement caching, fallback rules for new users, and monitoring for data drift, latency and offline/online metric gaps.
The supplied starter builds a tiny in-memory ratings table, pivots it to a user–item matrix, computes cosine similarity between user vectors, finds the single most similar user to a target, and recommends that neighbour's highest-rated unseen items. It implements user-based collaborative filtering with cosine similarity, not a neural collaborative filtering model.
matrix = ratings.pivot_table(index="user", columns="item", values="rating").fillna(0)
user_similarity = pd.DataFrame(
cosine_similarity(matrix),
index=matrix.index,
columns=matrix.index,
)
target_user = "user_1"
neighbor = user_similarity[target_user].drop(target_user).idxmax()
unseen_items = matrix.loc[target_user][matrix.loc[target_user] == 0].index
scores = matrix.loc[neighbor, unseen_items].sort_values(ascending=False)The code implements user-based nearest-neighbour collaborative filtering using cosine similarity and contains no neural network, no embedding layers, no ranking loss or negative sampling, and uses a synthetic six-user toy dataset that cannot validate ranking performance.
Proposed extension: replace the similarity-based logic with a neural collaborative filtering model (user/item embeddings + interaction MLP), train with negative sampling and evaluate Hit Rate@K and NDCG on a realistic dataset.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.