Is there existing software for discriminative reranking, such as that used by the Charniak NLP parser, Shen, Sarkar, and Och's parser or Shen and Joshi's techniques? I'd like something that I can easily adapt for my own uses, which are similar to parse reranking.
Charniak-Johnson Reranking
The source code for the Charniak-Johnson (CJ) reranking parser is freely available, you can download a copy here.
The reranker is a separate code module that takes as input n-best lists of parses, so it's trivial to decouple it from the parsing front end.
SVM-rank
Alternatively, the package SVM-rank, from Thorsten Joachim's lab at Cornell, is a general purpose ranker. It might be easier to go with this package, if what you want to do deviates significantly from what's being done by the Charniak-Johnson parser.