Install needed packages from requirements.txt.
Download treebank:

    import nltk
    nltk.download('treebank')

python pcfg_grammar.py train        Start training model for generating PCFG, generated grammar is saved in 'grammar.pickl' in same directory.

python pcfg_grammar.py evaluate     Grammar in 'grammar.pickl' is evaluated on test dataset, Precision, Recall and F1 score metrics are reported. 
                 
python pcfg_grammar.py test 'your_sentence'     creates and prints a parse tree for given sentence using grammar saved in 'grammar.pickl'. 

Trained model (PCFG Grammar) can be downloaded from: https://drive.google.com/open?id=1ciamamWs6XDXhdCeGZ3tEBUtj59ypY13

cky_parser.py       contains CKY parser implementation.
pcfg_grammar.py     contains driver code and pcfg estimation.
grammar.pickl       saved pcfg grammar.