the ratio of BLEU

[midnightsolarus]

I was wondering how much of the ratio of the modified n gram in BLEU-2 ,3 ,and 4. And if possible how to change the proportion? Or does the calculation only purely specify the specified n gram and not a proportion to the other n grams?

I mean , theoritically speaking BLEU-4 would have 0.25 , 0.25 , 0.25 ,0.25 proportion for n-gram 1 ,2,3,and 4 and then it's computed to become the BLEU-4 score. Does this wrapper do that?