Module openai_gpt

GPT (Radford et al.)

Implementation of the GPT2 language model (Improving Language Understanding by Generative Pre-Training Radford, Narasimhan, Salimans, Sutskever 2018). The base model is implemented in the openai_gpt_model::OpenAiGptModel struct. The model also includes a language model head: openai_gpt_model::OpenAIGPTLMHeadModel implementing the common generation_utils::LanguageGenerator trait shared between the models used for generation (see pipelines for more information).

Model set-up and pre-trained weights loading

All models expect the following resources:

• Configuration file expected to have a structure following the Transformers library
• Model weights are expected to have a structure and parameter names following the Transformers library. A conversion using the Python utility scripts is required to convert the .bin weights to the .ot format.
• GptTokenizer using a vocab.txt vocabulary and merges.txt 2-gram merges

Pretrained models are available and can be downloaded using RemoteResources.

use tch::{nn, Device};
use rust_bert::gpt2::Gpt2Config;
use rust_bert::openai_gpt::OpenAiGptModel;
use rust_bert::resources::{LocalResource, ResourceProvider};
use rust_bert::Config;
use rust_tokenizers::tokenizer::OpenAiGptTokenizer;

let config_resource = LocalResource {
    local_path: PathBuf::from("path/to/config.json"),
};
let vocab_resource = LocalResource {
    local_path: PathBuf::from("path/to/vocab.txt"),
};
let merges_resource = LocalResource {
    local_path: PathBuf::from("path/to/vocab.txt"),
};
let weights_resource = LocalResource {
    local_path: PathBuf::from("path/to/model.ot"),
};
let config_path = config_resource.get_local_path()?;
let vocab_path = vocab_resource.get_local_path()?;
let merges_path = merges_resource.get_local_path()?;
let weights_path = weights_resource.get_local_path()?;

let device = Device::cuda_if_available();
let mut vs = nn::VarStore::new(device);
let tokenizer: OpenAiGptTokenizer = OpenAiGptTokenizer::from_file(
    vocab_path.to_str().unwrap(),
    merges_path.to_str().unwrap(),
    true,
)?;
let config = Gpt2Config::from_file(config_path);
let gpt_model = OpenAiGptModel::new(&vs.root(), &config);
vs.load(weights_path)?;

Structs

OpenAIGPTLMHeadModel

GPT Language Modeling head

OpenAIGenerator

Language generation model based on the GPT architecture

OpenAiGptConfigResources

GPT Pretrained model config files

OpenAiGptMergesResources

GPT Pretrained model merges files

OpenAiGptModel

GPT Base model

OpenAiGptModelOutput

Container for the OpenAI GPT model output.

OpenAiGptModelResources

GPT Pretrained model weight files

OpenAiGptVocabResources

GPT Pretrained model vocab files

Type Aliases

OpenAiGptConfig

OpenAI GPT model configuration