rust-bert/examples/gpt2.rs
2020-06-23 16:54:46 +02:00

94 lines
3.5 KiB
Rust

// Copyright 2019-present, the HuggingFace Inc. team, The Google AI Language Team and Facebook, Inc.
// Copyright 2019 Guillaume Becquin
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
extern crate failure;
use rust_bert::gpt2::{
GPT2LMHeadModel, Gpt2Config, Gpt2ConfigResources, Gpt2MergesResources, Gpt2ModelResources,
Gpt2VocabResources,
};
use rust_bert::pipelines::generation::{Cache, LMHeadModel};
use rust_bert::resources::{download_resource, RemoteResource, Resource};
use rust_bert::Config;
use rust_tokenizers::{Gpt2Tokenizer, Tokenizer, TruncationStrategy};
use tch::{nn, Device, Tensor};
fn main() -> failure::Fallible<()> {
// Resources set-up
let config_resource =
Resource::Remote(RemoteResource::from_pretrained(Gpt2ConfigResources::GPT2));
let vocab_resource =
Resource::Remote(RemoteResource::from_pretrained(Gpt2VocabResources::GPT2));
let merges_resource =
Resource::Remote(RemoteResource::from_pretrained(Gpt2MergesResources::GPT2));
let weights_resource =
Resource::Remote(RemoteResource::from_pretrained(Gpt2ModelResources::GPT2));
let config_path = download_resource(&config_resource)?;
let vocab_path = download_resource(&vocab_resource)?;
let merges_path = download_resource(&merges_resource)?;
let weights_path = download_resource(&weights_resource)?;
// Set-up masked LM model
let device = Device::Cpu;
let mut vs = nn::VarStore::new(device);
let tokenizer: Gpt2Tokenizer = Gpt2Tokenizer::from_file(
vocab_path.to_str().unwrap(),
merges_path.to_str().unwrap(),
false,
);
let config = Gpt2Config::from_file(config_path);
let gpt2_model = GPT2LMHeadModel::new(&vs.root(), &config);
vs.load(weights_path)?;
// Define input
let input = ["One two three four five six seven eight nine ten eleven"];
let tokenized_input =
tokenizer.encode_list(input.to_vec(), 128, &TruncationStrategy::LongestFirst, 0);
let max_len = tokenized_input
.iter()
.map(|input| input.token_ids.len())
.max()
.unwrap();
let tokenized_input = tokenized_input
.iter()
.map(|input| input.token_ids.clone())
.map(|mut input| {
input.extend(vec![0; max_len - input.len()]);
input
})
.map(|input| Tensor::of_slice(&(input)))
.collect::<Vec<_>>();
let input_tensor = Tensor::stack(tokenized_input.as_slice(), 0).to(device);
// Forward pass
let (output, _, _, _, _) = gpt2_model
.forward_t(
&Some(input_tensor),
Cache::None,
&None,
&None,
&None,
&None,
None,
&None,
false,
)
.unwrap();
let next_word_id = output.get(0).get(-1).argmax(-1, true).int64_value(&[0]);
let next_word = tokenizer.decode(vec![next_word_id], true, true);
println!("Provided input: {}", input[0]);
println!("Next word: {}", next_word);
Ok(())
}