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118 lines
2.8 KiB
Ruby
118 lines
2.8 KiB
Ruby
$:.unshift File.dirname($0)
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require "set"
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require "dbscan"
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class SUBCLU
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def initialize(measure)
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@measure = measure
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end
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#cluster in the first dimension
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def subclu1(db, eps, min_pts, dimension_blacklist)
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c_and_s = Hash.new
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attributes = []; db.first.each_index {|attribute| attributes.push Set.new([attribute])}
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attributes.each do |attribute|
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if !dimension_blacklist.include?(attribute.to_a.first)
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dbscan = DBscan.new( @measure.new(attribute) )
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c_a = dbscan.run(db, eps, min_pts)
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if !c_a.empty?
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c_and_s[ attribute ] = c_a
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end
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end
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end
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return c_and_s
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end
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def generate_candidate_subspaces(c_and_s, dimension_blacklist)
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c_and_s_next = Hash.new
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#create candidate subspaces
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c_and_s.each_key do |s_1|
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c_and_s.each_key do |s_2|
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if (s_1-s_2).size == 1
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subspace = s_1+s_2
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if ( (dimension_blacklist - subspace.to_a).eql?(dimension_blacklist) && !filter_subspace?(subspace, c_and_s))
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c_and_s_next[(subspace)] = [] # clusters in higher subspace aren't yet known
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end
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end
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end
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end
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return c_and_s_next
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end
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#filter subspaces
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def filter_subspace?(subspace, c_and_s)
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subspace.each do |dim|
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s_k = subspace - [dim]
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if c_and_s[s_k] == nil || c_and_s[s_k].empty?
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return true
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end
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end
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return false
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end
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#main method
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def run(db, eps, min_pts, max_dimensions = 5, dimension_blacklist = [])
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dimension_blacklist = Set.new(dimension_blacklist)
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results = []
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#cluster all subspaces in one dimension
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c_and_s = subclu1(db, eps, min_pts, dimension_blacklist)
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results.push c_and_s
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while !c_and_s.empty? && results.size < max_dimensions
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c_and_s_next = generate_candidate_subspaces(c_and_s, dimension_blacklist)
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to_add_to_c_and_s_next = Hash.new
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to_remove_c_and_s_next = []
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c_and_s_next.each_pair do |subspace, clusters|
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best_subspace = nil
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best_subspace_cluster_count = (2**(0.size * 8 -2) -1) # maximum fixnum value
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subspace.each do |dim|
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s_k = subspace - [dim]
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cluster_count = c_and_s[s_k].map {|cluster| cluster.size}.reduce(:+)
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if (cluster_count < best_subspace_cluster_count)
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best_subspace_cluster_count = cluster_count
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best_subspace = s_k
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end
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end
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clusters = []
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c_and_s[best_subspace].each do |cl|
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dbscan = DBscan.new( @measure.new(subspace) )
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clusters += dbscan.run(cl, eps, min_pts)
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if not clusters.empty?
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to_add_to_c_and_s_next[subspace] = clusters
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else
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to_remove_c_and_s_next.push(subspace)
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end
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end
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end
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to_add_to_c_and_s_next.each_pair do |subspace, clusters|
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c_and_s_next[subspace] = clusters
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end
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to_remove_c_and_s_next.each do |subspace|
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c_and_s_next.delete(subspace)
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end
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results.push c_and_s_next if not c_and_s_next.empty?
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c_and_s = c_and_s_next
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end
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return results
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end
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end
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