Avoid Auto-Rebuild of LSI Indexes

[tra38]

ClassifierReborn::Summarizer.perform_lsi uses a neat trick to avoid LSI's default behavior of "auto-rebuilding" the index after every time a person adds new content .

def perform_lsi(chunks, count, separator)
    lsi = ClassifierReborn::LSI.new auto_rebuild: false
    chunks.each { \|chunk\| lsi << chunk unless chunk.strip.empty? \|\| chunk.strip.split.size == 1 }
    lsi.build_index
    summaries = lsi.highest_relative_content count
    summaries.reject { \|chunk\| !summaries.include? chunk }.map(&:strip).join(separator)
end

This could be useful behavior to have.