tokenizers.bpe - R package for Byte Pair Encoding

This repository contains an R package which is an Rcpp wrapper around the YouTokenToMe C++ library

• YouTokenToMe is an unsupervised text tokenizer focused on computational efficiency
• It currently implements fast Byte Pair Encoding (BPE) [Sennrich et al.]
• YouTokenToMe is available at https://github.com/VKCOM/YouTokenToMe
• Note that the flat_hash_map used in YouTokenToMe was replaced by parallel-hashmap

Features

The R package allows you to

• build a Byte Pair Encoding (BPE) model
• apply the model to encode text
• apply the model to decode ids back to text

Installation

• For regular users, install the package from your local CRAN mirror install.packages("tokenizers.bpe")
• For installing the development version of this package: remotes::install_github("bnosac/tokenizers.bpe")

Look to the documentation of the functions

help(package = "tokenizers.bpe")

Example

• As an example, let’s take some training data containing questions asked in Belgian Parliament in 2017 and focus on French text only.

library(tokenizers.bpe)
data(belgium_parliament, package = "tokenizers.bpe")
x <- subset(belgium_parliament, language == "french")
writeLines(text = x$text, con = "traindata.txt")

• Train a model on text data and inspect the vocabulary

model <- bpe("traindata.txt", coverage = 0.999, vocab_size = 5000)
model

Byte Pair Encoding model trained with YouTokenToMe
  size of the vocabulary: 5000
  model stored at: C:/Users/Jan/Dropbox/Work/RForgeBNOSAC/BNOSAC/tokenizers.bpe/youtokentome.bpe

str(model$vocabulary)

'data.frame':   5000 obs. of  2 variables:
 $ id     : int  0 1 2 3 4 5 6 7 8 9 ...
 $ subword: chr  "<PAD>" "<UNK>" "<BOS>" "<EOS>" ...

• Use the model to encode text

text <- c("L'appartement est grand & vraiment bien situe en plein centre",
          "Proportion de femmes dans les situations de famille monoparentale.")
bpe_encode(model, x = text, type = "subwords")

[[1]]
 [1] "▁L'"     "app"     "ar"      "tement"  "▁est"    "▁grand"  "▁"       "&"       "▁v"      "r"       "ai"      "ment"    "▁bien"   "▁situe"  "▁en"     "▁plein"  "▁centre"

[[2]]
 [1] "▁Pro"        "por"         "tion"        "▁de"         "▁femmes"     "▁dans"       "▁les"        "▁situations" "▁de"         "▁famille"    "▁mon"        "op"          "ar"          "ent"         "ale." 

bpe_encode(model, x = text, type = "ids")

[[1]]
 [1]  421  327   98  554  178 1521    4    1  117   11  101   99  679 4599  113 3702 2126

[[2]]
 [1] 1529 4878   92   76 2321  162  108 4099   76 3218  791  312   98   87 2546

• Use the model to decode byte pair encodings back to text

x <- bpe_encode(model, x = text, type = "ids")
bpe_decode(model, x)

[[1]]
[1] "L'appartement est grand <UNK> vraiment bien situe en plein centre"

[[2]]
[1] "Proportion de femmes dans les situations de famille monoparentale."

Support in text mining

Need support in text mining? Contact BNOSAC: http://www.bnosac.be