class_docstr: An accumulator object capable of computing NIST score using multiple references.
docstr: Return the current NIST score, according to the accumulated counts.
docstr_tok: ["Return","the","current","NIST","score",",","according","to","the","accumulated","counts","."]
code: def nist(self):
      """Return the current NIST score, according to the accumulated counts."""
      # 1st NIST term
      hit_infos = [0.0 for _ in range(self.max_ngram)]
      for n in range(self.max_ngram):
          for hit_ngrams in self.hit_ngrams[n]:
              hit_infos[n] += sum(
                  self.info(ngram) * hits
                  for ngram, hits in hit_ngrams.items()
              )
      total_lens = [
          sum(self.cand_lens[n]) for n in range(self.max_ngram)
      ]
      nist_sum = sum(
          old_div(hit_info, total_len)
          for hit_info, total_len in zip(hit_infos, total_lens)
      )
      # length penalty term
      bp = self.nist_length_penalty(
          sum(self.cand_lens[0]), self.avg_ref_len
      )
      return bp * nist_sum
  
imports: from __future__ import unicode_literals
  from __future__ import division
  from builtins import zip
  from builtins import range
  from past.utils import old_div
  from builtins import object
  from collections import defaultdict
  import math
  import re
label_desc: Use image node_id 7 for calling the NISTScore obj's underlying member method code with example usage: obj.nist() and returns: unknown