IDD3 (Propositional Idea Density from Dependency Trees) is a Python library that can extract propositions from a sentence, given its dependency tree. Propositions are extracted according to Chand et al.'s rubric [1].

To install IDD3 on your system, run can run:

$ git clone https://github.com/andrecunha/idd3.git
$ cd idd3
$ python setup.py install

You might want to install IDD3 inside a virtualenv.

IDD3 ships with a run.py file, that illustrates how the library can be accessed. This file can be used to easily analyze sentences and see the system's output. You can use this file to analyze either a raw sentence, or its dependency tree, stored in a CoNLL-X file. In order to analyze raw sentences, follow these steps:

1. run.py uses the Stanford Parser to extract the dependency tree. Download the latest version of it at http://nlp.stanford.edu/software/lex-parser.shtml#Download, and extract it where you want.
2. Change the variable stanford_path in run.py to point to the path where you extracted the parser in the previous step (the default value is ~/Develop/stanford_tools/).
3. Place the sentences you want to analyze in a file, let's say input.txt, one sentence per line.
4. Run IDD3 as python run.py input.txt

If you have a CoNLL-X file, say input.conll, that already has the dependency trees for the sentences you want IDD3 to analyze, you can just run python run.py input.conll, with no need to configure the Stanford Parser.

[1] V. Chand, K. Baynes, L. Bonnici, and S. T. Farias, Analysis of Idea Density (AID): A Manual, University of California at Davis, 2010. Available at http://mindbrain.ucdavis.edu/labs/Baynes/AIDManual.ChandBaynesBonniciFarias.1.26.10.pdf.