alt Hacker NewsFun fact: cosine similarity's first use in recommendation systems to recommend usenet groups.
(https://dl.acm.org/doi/epdf/10.1145/192844.192905 although they don't call it cosine similarity; they do compute a "correlation coefficient" between two people by adding together the products of scores each gave to a post)
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zahlman • yesterday at 6:49 PM
> they do compute a "correlation coefficient" between two people by adding together the products of scores each gave to a post
I've heard the term "cosine similarity" before but not really looked into it. What does this computation have to do with trigonometry?
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The Pearson correlation coefficient is covariance normalised to the range [-1, 1] by dividing with the standard deviations (https://en.wikipedia.org/wiki/Pearson_correlation_coefficien...). So not quite same as the normalised scalar product, even though the formulas look related.