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metadata
language:
  - es
  - af
  - ar
  - arz
  - as
  - bn
  - fr
  - sw
  - eu
  - ca
  - zh
  - en
  - hi
  - ur
  - id
  - pt
  - vi
  - gu
  - kn
  - ml
  - mr
  - ta
  - te
  - yo
  - de
tags:
  - kenlm
  - perplexity
  - n-gram
  - kneser-ney
  - bigscience
license: mit
datasets:
  - wikipedia
  - oscar
duplicated_from: edugp/kenlm

Fork of edugp/kenlm

  • adds German wikipedia model.

KenLM models

This repo contains several KenLM models trained on different tokenized datasets and languages.
KenLM models are probabilistic n-gram languge models that models. One use case of these models consist on fast perplexity estimation for filtering or sampling large datasets. For example, one could use a KenLM model trained on French Wikipedia to run inference on a large dataset and filter out samples that are very unlike to appear on Wikipedia (high perplexity), or very simple non-informative sentences that could appear repeatedly (low perplexity).

  • {language}.arpa.bin: The trained KenLM model binary
  • {language}.sp.model: The trained SentencePiece model used for tokenization
  • {language}.sp.vocab: The vocabulary file for the SentencePiece model

The models have been trained using some of the preprocessing steps from cc_net, in particular replacing numbers with zeros and normalizing punctuation. So, it is important to keep the default values for the parameters: lower_case, remove_accents, normalize_numbers and punctuation when using the pre-trained models in order to replicate the same pre-processing steps at inference time.

Dependencies

  • KenLM: pip install https://github.com/kpu/kenlm/archive/master.zip
  • SentencePiece: pip install sentencepiece

Example:

from model import KenlmModel


# Load model trained on English wikipedia
model = KenlmModel.from_pretrained("wikipedia", "en")

# Get perplexity
model.get_perplexity("I am very perplexed")
# 341.3 (low perplexity, since sentence style is formal and with no grammar mistakes)

model.get_perplexity("im hella trippin")
# 46793.5 (high perplexity, since the sentence is colloquial and contains grammar mistakes)

In the example above we see that, since Wikipedia is a collection of encyclopedic articles, a KenLM model trained on it will naturally give lower perplexity scores to sentences with formal language and no grammar mistakes than colloquial sentences with grammar mistakes.