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# File 'lib/neighbor/reranking.rb', line 3
def self.rrf(first_ranking, *rankings, k: 60)
rankings.unshift(first_ranking)
ranks = []
results = []
rankings.each do |ranking|
ranks << ranking.map.with_index.to_h { |v, i| [v, i + 1] }
results.concat(ranking)
end
results =
results.uniq.map do |result|
score =
ranks.sum do |rank|
r = rank[result]
r ? 1.0 / (k + r) : 0.0
end
{result: result, score: score}
end
results.sort_by { |v| -v[:score] }
end
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