Conversion of NLTK tree to PTB format

[anirudh708]

The convert_tree() function is not able to form dependencies for a nltk tree and an alternate conversion from nltk to ptb doesnt work

[via http://stackoverflow.com/a/29614388/1118542]

[dmcc]

Thanks for the report. convert_tree() isn't designed to take NLTK Tree objects as arguments -- only strings of Penn Treebank trees (though it's easy to convert a Tree to this type of string with str()).

If you're using the Subprocess backend, there's a debug=True flag that you can pass to convert_tree() which may provide additional information.

If this doesn't help, please provide more details (ideally the whole sequence of PyStanfordDependencies related commands including which backend, version of SD, the string of the tree you want to convert, etc.).