An open source automatic summarization tool.
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Shuca is an automatic summarization software. It can summarize a single document (Single-Document Summarization) and multiple documents (Multi-Document Summarization) as an input. As for summarizing documents written in Japanese, see


  • Shuca extracts important sentences from among input sentences in an input so as to maximize the sum of importance of those within the given length limitation.

Sindle Document Summarization

  • Shuca regards a task of single-document summarization as an instance of knapsack problem; it hence searches for a best combination of an input through the dynamic programming knapsak algorithm.

Multi-Document Summarization

  • Shuca regards a task of multi-document summarization as an instance of maximum coverage knapsack problem; it hence searches for an approximate solution of a best comination of input sentences through the greedy algorithm.


  • Each line in an input must be one sentence; Shuca processes each line as an unit of summarization.
  • As preprocess words in an input should be stemmed beforehand.


Download and put files in your directory; no installation is needed.


In dat directory, there are some sample files. automatic_summarization.txt is a text file in which the first two paragraphs of an wikipedia article, ``Automatic Summarization", is. automatic_summarization.sent.txt and `automatic_summarization.sent.stem.txt` are a sentence-splitted and stemmed version of that respectively. Please test a following command:

$ ./lib/ -e < ./dat/automatic_summarization.sent.stem.txt
  • -d Specify an external dictionary. In default setting, Shuca uses a default dictionary.
  • -e To summarize texts written in English, -e option must be specified.
  • -l Specify summarization length in the number of words. For Instance, If speficy -l 200, Shuca outputs a summary within 200 words. Default summarization length is 200 words.
  • -m Perform multi-document summarization. Without this option, single-document summarization is performed.
  • -s Set summarization length with the number of sentences. For instance, If specify -s 3, three sentences will be output as an output summary.


  • Parameters packed together with the software are now roughly set by the developer, and will be replaced with ones estimated through machine learning.


Hitoshi Nishikawa