|
| 1 | +{ |
| 2 | + "cells": [ |
| 3 | + { |
| 4 | + "cell_type": "markdown", |
| 5 | + "metadata": {}, |
| 6 | + "source": [ |
| 7 | + "# Multi-lingual models" |
| 8 | + ] |
| 9 | + }, |
| 10 | + { |
| 11 | + "cell_type": "markdown", |
| 12 | + "metadata": {}, |
| 13 | + "source": [ |
| 14 | + "Most of the models available in this library are mono-lingual models (English, Chinese and German). A few\n", |
| 15 | + "multi-lingual models are available and have a different mechanisms than mono-lingual models.\n", |
| 16 | + "This page details the usage of these models.\n", |
| 17 | + "\n", |
| 18 | + "The two models that currently support multiple languages are BERT and XLM." |
| 19 | + ] |
| 20 | + }, |
| 21 | + { |
| 22 | + "cell_type": "markdown", |
| 23 | + "metadata": {}, |
| 24 | + "source": [ |
| 25 | + "## XLM" |
| 26 | + ] |
| 27 | + }, |
| 28 | + { |
| 29 | + "cell_type": "markdown", |
| 30 | + "metadata": {}, |
| 31 | + "source": [ |
| 32 | + "XLM has a total of 10 different checkpoints, only one of which is mono-lingual. The 9 remaining model checkpoints can\n", |
| 33 | + "be split in two categories: the checkpoints that make use of language embeddings, and those that don't" |
| 34 | + ] |
| 35 | + }, |
| 36 | + { |
| 37 | + "cell_type": "markdown", |
| 38 | + "metadata": {}, |
| 39 | + "source": [ |
| 40 | + "### XLM & Language Embeddings" |
| 41 | + ] |
| 42 | + }, |
| 43 | + { |
| 44 | + "cell_type": "markdown", |
| 45 | + "metadata": {}, |
| 46 | + "source": [ |
| 47 | + "This section concerns the following checkpoints:\n", |
| 48 | + "\n", |
| 49 | + "- `xlm-mlm-ende-1024` (Masked language modeling, English-German)\n", |
| 50 | + "- `xlm-mlm-enfr-1024` (Masked language modeling, English-French)\n", |
| 51 | + "- `xlm-mlm-enro-1024` (Masked language modeling, English-Romanian)\n", |
| 52 | + "- `xlm-mlm-xnli15-1024` (Masked language modeling, XNLI languages)\n", |
| 53 | + "- `xlm-mlm-tlm-xnli15-1024` (Masked language modeling + Translation, XNLI languages)\n", |
| 54 | + "- `xlm-clm-enfr-1024` (Causal language modeling, English-French)\n", |
| 55 | + "- `xlm-clm-ende-1024` (Causal language modeling, English-German)\n", |
| 56 | + "\n", |
| 57 | + "These checkpoints require language embeddings that will specify the language used at inference time. These language\n", |
| 58 | + "embeddings are represented as a tensor that is of the same shape as the input ids passed to the model. The values in\n", |
| 59 | + "these tensors depend on the language used and are identifiable using the `lang2id` and `id2lang` attributes\n", |
| 60 | + "from the tokenizer.\n", |
| 61 | + "\n", |
| 62 | + "Here is an example using the `xlm-clm-enfr-1024` checkpoint (Causal language modeling, English-French):" |
| 63 | + ] |
| 64 | + }, |
| 65 | + { |
| 66 | + "cell_type": "code", |
| 67 | + "execution_count": null, |
| 68 | + "metadata": {}, |
| 69 | + "outputs": [], |
| 70 | + "source": [ |
| 71 | + "import torch\n", |
| 72 | + "from transformers import XLMTokenizer, XLMWithLMHeadModel\n", |
| 73 | + "tokenizer = XLMTokenizer.from_pretrained(\"xlm-clm-enfr-1024\")\n", |
| 74 | + "model = XLMWithLMHeadModel.from_pretrained(\"xlm-clm-enfr-1024\")" |
| 75 | + ] |
| 76 | + }, |
| 77 | + { |
| 78 | + "cell_type": "markdown", |
| 79 | + "metadata": {}, |
| 80 | + "source": [ |
| 81 | + "The different languages this model/tokenizer handles, as well as the ids of these languages are visible using the\n", |
| 82 | + "`lang2id` attribute:" |
| 83 | + ] |
| 84 | + }, |
| 85 | + { |
| 86 | + "cell_type": "code", |
| 87 | + "execution_count": null, |
| 88 | + "metadata": {}, |
| 89 | + "outputs": [ |
| 90 | + { |
| 91 | + "data": { |
| 92 | + "text/plain": [ |
| 93 | + "{'en': 0, 'fr': 1}" |
| 94 | + ] |
| 95 | + }, |
| 96 | + "execution_count": null, |
| 97 | + "metadata": {}, |
| 98 | + "output_type": "execute_result" |
| 99 | + } |
| 100 | + ], |
| 101 | + "source": [ |
| 102 | + "print(tokenizer.lang2id)" |
| 103 | + ] |
| 104 | + }, |
| 105 | + { |
| 106 | + "cell_type": "markdown", |
| 107 | + "metadata": {}, |
| 108 | + "source": [ |
| 109 | + "These ids should be used when passing a language parameter during a model pass. Let's define our inputs:" |
| 110 | + ] |
| 111 | + }, |
| 112 | + { |
| 113 | + "cell_type": "code", |
| 114 | + "execution_count": null, |
| 115 | + "metadata": {}, |
| 116 | + "outputs": [], |
| 117 | + "source": [ |
| 118 | + "input_ids = torch.tensor([tokenizer.encode(\"Wikipedia was used to\")]) # batch size of 1" |
| 119 | + ] |
| 120 | + }, |
| 121 | + { |
| 122 | + "cell_type": "markdown", |
| 123 | + "metadata": {}, |
| 124 | + "source": [ |
| 125 | + "We should now define the language embedding by using the previously defined language id. We want to create a tensor\n", |
| 126 | + "filled with the appropriate language ids, of the same size as input_ids. For english, the id is 0:" |
| 127 | + ] |
| 128 | + }, |
| 129 | + { |
| 130 | + "cell_type": "code", |
| 131 | + "execution_count": null, |
| 132 | + "metadata": {}, |
| 133 | + "outputs": [], |
| 134 | + "source": [ |
| 135 | + "language_id = tokenizer.lang2id['en'] # 0\n", |
| 136 | + "langs = torch.tensor([language_id] * input_ids.shape[1]) # torch.tensor([0, 0, 0, ..., 0])\n", |
| 137 | + "# We reshape it to be of size (batch_size, sequence_length)\n", |
| 138 | + "langs = langs.view(1, -1) # is now of shape [1, sequence_length] (we have a batch size of 1)" |
| 139 | + ] |
| 140 | + }, |
| 141 | + { |
| 142 | + "cell_type": "markdown", |
| 143 | + "metadata": {}, |
| 144 | + "source": [ |
| 145 | + "You can then feed it all as input to your model:" |
| 146 | + ] |
| 147 | + }, |
| 148 | + { |
| 149 | + "cell_type": "code", |
| 150 | + "execution_count": null, |
| 151 | + "metadata": {}, |
| 152 | + "outputs": [], |
| 153 | + "source": [ |
| 154 | + "outputs = model(input_ids, langs=langs)" |
| 155 | + ] |
| 156 | + }, |
| 157 | + { |
| 158 | + "cell_type": "markdown", |
| 159 | + "metadata": {}, |
| 160 | + "source": [ |
| 161 | + "The example [run_generation.py](https://github.com/huggingface/transformers/blob/master/examples/text-generation/run_generation.py)\n", |
| 162 | + "can generate text using the CLM checkpoints from XLM, using the language embeddings." |
| 163 | + ] |
| 164 | + }, |
| 165 | + { |
| 166 | + "cell_type": "markdown", |
| 167 | + "metadata": {}, |
| 168 | + "source": [ |
| 169 | + "### XLM without Language Embeddings" |
| 170 | + ] |
| 171 | + }, |
| 172 | + { |
| 173 | + "cell_type": "markdown", |
| 174 | + "metadata": {}, |
| 175 | + "source": [ |
| 176 | + "This section concerns the following checkpoints:\n", |
| 177 | + "\n", |
| 178 | + "- `xlm-mlm-17-1280` (Masked language modeling, 17 languages)\n", |
| 179 | + "- `xlm-mlm-100-1280` (Masked language modeling, 100 languages)\n", |
| 180 | + "\n", |
| 181 | + "These checkpoints do not require language embeddings at inference time. These models are used to have generic\n", |
| 182 | + "sentence representations, differently from previously-mentioned XLM checkpoints." |
| 183 | + ] |
| 184 | + }, |
| 185 | + { |
| 186 | + "cell_type": "markdown", |
| 187 | + "metadata": {}, |
| 188 | + "source": [ |
| 189 | + "## BERT" |
| 190 | + ] |
| 191 | + }, |
| 192 | + { |
| 193 | + "cell_type": "markdown", |
| 194 | + "metadata": {}, |
| 195 | + "source": [ |
| 196 | + "BERT has two checkpoints that can be used for multi-lingual tasks:\n", |
| 197 | + "\n", |
| 198 | + "- `bert-base-multilingual-uncased` (Masked language modeling + Next sentence prediction, 102 languages)\n", |
| 199 | + "- `bert-base-multilingual-cased` (Masked language modeling + Next sentence prediction, 104 languages)\n", |
| 200 | + "\n", |
| 201 | + "These checkpoints do not require language embeddings at inference time. They should identify the language\n", |
| 202 | + "used in the context and infer accordingly." |
| 203 | + ] |
| 204 | + }, |
| 205 | + { |
| 206 | + "cell_type": "markdown", |
| 207 | + "metadata": {}, |
| 208 | + "source": [ |
| 209 | + "## XLM-RoBERTa" |
| 210 | + ] |
| 211 | + }, |
| 212 | + { |
| 213 | + "cell_type": "markdown", |
| 214 | + "metadata": {}, |
| 215 | + "source": [ |
| 216 | + "XLM-RoBERTa was trained on 2.5TB of newly created clean CommonCrawl data in 100 languages. It provides strong\n", |
| 217 | + "gains over previously released multi-lingual models like mBERT or XLM on downstream taks like classification,\n", |
| 218 | + "sequence labeling and question answering.\n", |
| 219 | + "\n", |
| 220 | + "Two XLM-RoBERTa checkpoints can be used for multi-lingual tasks:\n", |
| 221 | + "\n", |
| 222 | + "- `xlm-roberta-base` (Masked language modeling, 100 languages)\n", |
| 223 | + "- `xlm-roberta-large` (Masked language modeling, 100 languages)" |
| 224 | + ] |
| 225 | + } |
| 226 | + ], |
| 227 | + "metadata": {}, |
| 228 | + "nbformat": 4, |
| 229 | + "nbformat_minor": 4 |
| 230 | +} |
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