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    Code for QANTA, described in the following paper:
    A Neural Network for Factoid Question Answering over Paragraphs
    Mohit Iyyer, Jordan Boyd-Graber, Leonardo Claudino, Richard Socher, and Hal Daumé III.
    Empirical Methods in Natural Language Processing (EMNLP), 2014

    Contact Mohit at [email protected] for questions or comments.
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What is it?
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    QANTA is a "question answering neural network with trans-sentential averaging". 
    Enclosed in this package is code to train QANTA along with
    two datasets (history and literature questions). We also provide code to
    evaluate trained models and transform other data into the format that QANTA requires.


Dependencies:
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    - Python (mine: 2.7.7), numpy (mine: 1.8.1), scikit-learn (mine: 0.14.1), nltk (mine: 2.0.4)
    - Tip: an easy way to get all the dependencies at once is to download the free Anaconda 
      Python distribution: http://continuum.io/downloads

    - People have encountered bugs with numpy versions older than 1.7 and older sklearn versions,
      but newer versions shouldn't cause any problems. Let me know if you run into any issues.


Data specifics:
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    Since we used proprietary data from NAQT in the experiments reported in our paper,
    the provided datasets are significantly smaller than the ones we used.
    In particular, the history dataset contains 1,713 questions (8,149 sentences) and 
    the literature dataset contains 2,246 questions (10,552 sentences). These questions (and
    questions from other categories) are publically available at:
    https://code.google.com/p/protobowl/downloads/detail?name=shuffled.json

        Sample question:
            This author describes the last Neanderthals being killed by Homo sapiens in his The 
            Inheritors, and a lone British naval officer hallucinates survival on a barren rock
            in his Pincher Martin. In another of his novels, the title entity speaks to Simon 
            atop a wooden stick; later in that novel, the followers of Jack steal Piggy's 
            glasses and break the conch shell of Ralph, their former chief. For 10 points, 
            name this British author who described boys on a formerly deserted island in his 
            Lord of the Flies.

        A: Lord of the Flies


How do I train a model?
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    - To train a model on the history dataset with default parameters, use the following command:
        python qanta.py

    - To train a model on the literature dataset, use this command:
        python qanta.py -data 'data/lit_split' -We 'data/lit_We' -b 341 -o 'models/lit_params'

    - For detailed explanation of QANTA's hyperparameters, use the help command:
        python qanta.py -h

    - You can get better performance to a point (along with a longer training time) by increasing 
      the number of training epochs. For the results reported in the paper I ran the script for 
      50 epochs. You can also train faster by increasing the number of cores used (default=6,
      change as per your machine's specs).

    - The resulting model is pickled and dumped into the models directory. 


Okay, I've trained a model. How do I evaluate it?
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    - Use the evaluate script (see following example):
        python evaluate_qanta.py -data data/hist_split -model models/hist_params

    - This script will train a model on QANTA's learned representations and output both overall 
      accuracy as well as accuracy at each sentence position of the question. In addition, it
      will train BoW and BoW-DT baseline models (as described in the paper) for comparison.

    - As a point of comparison, I get around 60% accuracy on the history dataset and 54% accuracy on 
      literature with QANTA, which beats the BoW-DT baseline by 10-15% and the BoW baseline by ~20%.
      This shows that QANTA is still effective on smaller datasets.


That's cool. But how do I feed my own data into QANTA?
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    - A preprocessing script has been provided to dependency parse your own questions and 
      convert them into the tree format required by QANTA. You'll need to download the Stanford parser
      (http://nlp.stanford.edu/software/lex-parser.shtml) to run the scripts. Also, a modified version
      of the parsing script lexparser.sh has been provided to output only typed dependencies.


Great. What if I want to modify QANTA's code for my own task?
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    - A single processor version of QANTA has been provided along with a toy dataset for development
      purposes. If you mess with the propagation functions in rnn/propagation.py, you'll want to 
      check your gradients on the toy dataset by running the following command:
        python single_proc_qanta.py


What should I cite if I use this code?
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    @inproceedings{Iyyer:Boyd-Graber:Claudino:Socher:Daume-2014,
            Title = {A Neural Network for Factoid Question Answering over Paragraphs},
            Author = {Mohit Iyyer and Jordan Boyd-Graber and Leonardo Claudino and Richard Socher 
            and Hal Daume III},
            Booktitle = {Empirical Methods in Natural Language Processing},
            Year = {2014},
            Location = {Doha, Qatar},
        }