corpus_bleu() got an unexpected keyword argument 'emulate_multibleu'

[norahsakal]

'emulate_multibleu' seems to be deprecated according to Removed emulate_multibleu and backoff params
Do you have any suggestions for achieving the same performance? Have you tried using 'smoothing_function' which seems to be a replacement for 'emulate_multibleu'?

Huge thanks for an amazing repository!

[sgrvinod]

Thank you!

Thanks for the heads-up, I'm probably using an older version. From a cursory look, it appears what was previously emulate_multibleu=True is now the default? I'll check and confirm.

I vaguely remember I tried the smoothing functions but maybe I wasn't too sure that they were needed. I ended up just setting the emulate_multibleu flag to True because I wanted to emulate the behaviour of multi-bleu.perl as it's widely used.

[jason718]

I think they make it default here: nltk/nltk@764dc8f

and comment:
nltk/nltk#1844 (comment)

[sgrvinod]

Merged, thanks.

[kmario23]

Just to link to the current signature from the official docs: nltk.translate.bleu_score.corpus_bleu

Below is a contrived example borrowed from the docs:

>>> from nltk.translate.bleu_score import corpus_bleu

>>> hyp1 = ['It', 'is', 'a', 'guide', 'to', 'action', 'which',
...         'ensures', 'that', 'the', 'military', 'always',
...         'obeys', 'the', 'commands', 'of', 'the', 'party']
>>> ref1a = ['It', 'is', 'a', 'guide', 'to', 'action', 'that',
...          'ensures', 'that', 'the', 'military', 'will', 'forever',
...          'heed', 'Party', 'commands']
>>> ref1b = ['It', 'is', 'the', 'guiding', 'principle', 'which',
...          'guarantees', 'the', 'military', 'forces', 'always',
...          'being', 'under', 'the', 'command', 'of', 'the', 'Party']
>>> ref1c = ['It', 'is', 'the', 'practical', 'guide', 'for', 'the',
...          'army', 'always', 'to', 'heed', 'the', 'directions',
...          'of', 'the', 'party']

>>> hyp2 = ['he', 'read', 'the', 'book', 'because', 'he', 'was',
...         'interested', 'in', 'world', 'history']
>>> ref2a = ['he', 'was', 'interested', 'in', 'world', 'history',
...          'because', 'he', 'read', 'the', 'book']

 >>> list_of_references = [[ref1a, ref1b, ref1c], [ref2a]]
 >>> hypotheses = [hyp1, hyp2]
 >>> corpus_bleu(list_of_references, hypotheses)

So, as we can see from this call, the emulate_multibleu kwarg is no longer supported. Hence, removing this will fix the issue.