# File lib/classifier/lsi.rb, line 176
    def proximity_array_for_content( doc, &block )
      return [] if needs_rebuild?
      
      content_node = node_for_content( doc, &block )
      result = 
        @items.keys.collect do |item|
          if $GSL
             val = content_node.search_vector * @items[item].search_vector.col
          else
             val = (Matrix[content_node.search_vector] * @items[item].search_vector)[0]
          end
          [item, val]
        end
      result.sort_by { |x| x[1] }.reverse
    end