Module rust_bert::models::pegasus

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Pegasus (Zhang et al.)

Implementation of the Pegasus language model (PEGASUS: Pre-training with Extracted Gap-sentences for Abstractive Summarization Zhang, Zhao, Saleh, Liu, 2019). The base model is implemented in the pegasus_model::PegasusModel struct and leverages an implementation that is broadly similar to BART. The model also includes a language model head: pegasus_model::PegasusForConditionalGeneration 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

A full working example is provided in examples/summarization_pegasus, run with cargo run --example summarization_pegasus. 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.
  • PegasusTokenizer using a spiece.model vocabulary and unigram model. Pretrained models are available and can be downloaded using RemoteResources.
use tch::{nn, Device};
use rust_bert::pegasus::{PegasusConfig, PegasusModel};
use rust_bert::resources::{LocalResource, ResourceProvider};
use rust_bert::Config;
use rust_tokenizers::tokenizer::PegasusTokenizer;

let config_resource = LocalResource {
    local_path: PathBuf::from("path/to/config.json"),
};
let vocab_resource = LocalResource {
    local_path: PathBuf::from("path/to/spiece.model"),
};
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 weights_path = weights_resource.get_local_path()?;

let device = Device::cuda_if_available();
let mut vs = nn::VarStore::new(device);
let tokenizer: PegasusTokenizer =
    PegasusTokenizer::from_file(vocab_path.to_str().unwrap(), false)?;
let config = PegasusConfig::from_file(config_path);
let pegasus_model = PegasusModel::new(&vs.root(), &config);
vs.load(weights_path)?;

Structs

Type Aliases