def proximity_norms_for_content(doc, &block)
      return [] if needs_rebuild?

      content_node = node_for_content(doc, &block)
      if $GSL && content_node.raw_norm.isnan?.all?
        puts "There are no documents that are similar to #{doc}"
      else
        content_node_norms(content_node)
      end
    end
def proximity_norms_for_content(doc, &block)
      return [] if needs_rebuild?

      content_node = node_for_content(doc, &block)
      if $GSL && content_node.raw_norm.isnan?.all?
        puts "There are no documents that are similar to #{doc}"
      else
        content_node_norms(content_node)
      end
    end
Similar to proximity_array_for_content, this function takes similar
 arguments and returns a similar array. However, it uses the normalized
 calculated vectors instead of their full versions. This is useful when
 you're trying to perform operations on content that is much smaller than
 the text you're working with. search uses this primitive.