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Pre-Training to Learn in Context

This repository contains the code of our ACL2023 paper:

Pre-Training to Learn in Context

In this work, we propose PICL (Pre-training for In-Context Learning), a framework to enhance the language models' in-context learning ability by pre-training the model on a large collection of ``intrinsic tasks'' in the general plain-text corpus using the simple language modeling objective. PICL encourages the model to infer and perform tasks by conditioning on the contexts while maintaining task generalization of pre-trained models.

PICL

1 Install

# setup environment with conda
conda create -n picl python=3.8
# install basic packages
pip3 install -r requirements.txt
conda install faiss-gpu -c pytorch
# install transformers & promptsource
pip3 install -e transformers
pip3 install -e promptsource

2 Prepare Plain-Text Corpus

Download OpenWebText, Wikicorpus, and Bookcorpus. Run tools/prepare_raw_data.py to get all full_documents and merge them:

python3 tools/prepare_raw_data.py /PATH/TO/openwebtext pretrain_data/raw/openwebtext.txt
python3 tools/prepare_raw_data.py /PATH/TO/wikicorpus pretrain_data/raw/wikicorpus.txt
python3 tools/prepare_raw_data.py /PATH/TO/bookcorpus pretrain_data/raw/bookcorpus.txt
cat pretrain_data/raw/openwebtext.txt pretrain_data/raw/wikicorpus.txt pretrain_data/raw/bookcorpus.txt > pretrain_data/raw/merge_no_shuf.txt
shuf -o pretrain_data/raw/merge_no_shuf.txt pretrain_data/raw/merge.txt

The "\n" tokens in full documents are replace by a special token "<@x(x!>" such that each document occupy a single line in the file.

3 Run the Pipeline

Run the entire pipeline in a toy setting (corpus size = 100K) with

bash pipeline.sh

${BASE_PATH} is the path of the directory of this project.

The details of each step in the pipeline are shown in the following sections.

4 Construct PICL Data

We release the constructed PICL data in this link.

You can check the same-intrinsic-task paragraphs by running python3 check_picl_data.py and then entering an interger index to pick a query and the retrieved paragraphs:

<details><summary>Latex Equation Translation</summary>

Input Paragraph Index >>>11156                                                         
##########  Query  ##########
ω p = I s ω s I p cos ⁡ ( α ) {\displaystyle {\boldsymbol {\omega }}_{\mathrm {p} }={\frac {{\boldsymbol {I}}_{\mathrm {s} }{\boldsymbol {\omega }}_{\mathrm {s} }}{{\boldsymbo
l {I}}_{\mathrm {p} }\cos({\boldsymbol {\alpha }})}}}

##########  Retrieved Paragraph #1  ##########
τ b ∗ = τ b ( ρ s − ρ f ) ( g ) ( D ) {\displaystyle \tau _{b}*={\frac {\tau _{b}}{(\rho _{s}-\rho _{f})(g)(D)}}}


##########  Retrieved Paragraph #2  ##########
M H ≤ ℏ c 3 8 π G k B T u {\displaystyle M_{\mathrm {H} }\leq {\frac {\hbar c^{3}}{8\pi Gk_{\mathrm {B} }T_{\mathrm {u} }}}}

...

</details> <details><summary>Question Answering</summary>

##########  Query  ##########
Question: Where would a gnarly off-road racer like Tanner Foust meet up with a frightened five-year-old child with leukemia? Answer: In a hospital, of course!


##########  Retrieved Paragraph #1  ##########
Question: What do a siren, an in-wall light switch, a sleep sensing iPhone dock, and a flood detector have in common? Answer: They are all SmartThings!


##########  Retrieved Paragraph #2  ##########
Question: Where do you find a one legged dog? Answer: Where you left it.
...

</details>

Here are some indices for interesting paragraphs. Try it out!

<details><summary>Indices</summary>

</details>

You can also constructe the PICL data from scratch following the instructions below.

4.1 Preprocessing and Toknization

Tokenize and store full documents and paragraphs into binary files.

Split full documents into paragraphs.
```
bash scripts/tools/process_corpus.sh
```
Process full document data. The scripts will generate .bin and .idx files.
```
bash scripts/tools/process_full_doc_data_gpt2.sh ${BASE_PATH}
```
Tokenize paragraphs in corpus. The scripts will generate .bin and .idx files.
```
bash scripts/tools/process_picl_data_gpt2.sh ${BASE_PATH}
```

NOTE

Since the corpus is large, the .bin file of full document data will be about 29G and the paragraph data will be about 13G. The data processing may take long, and there may be unexpected problems that stuck the process (like running out of CPU memories). To handle this issue, you can split the merge.txt file to multiple files like:

split -C 1000M merge.txt

And then, you can process the split files one by one (by setting different picl-data-name and bin-file-index in process_full_doc_data_gpt2.sh), each takes less time and has less risk of running into problems. Assume that you have generated two (.bin, .idx) pairs:

train_lm_1.bin
train_lm_1.idx
train_lm_2.bin
train_lm_2.idx

You can finally merge them by runing

bash scripts/tools/merge_bin_files.sh ${BASE_PATH}

which will merge the two pairs into train_lm_0.bin and train_lm_0.idx.

4.2 Retrival

Process training data for retriever. Construct hard negatives. The raw data and the preprocessed data can be downloaded from this link. To do data processing, put the raw datasets under data/ and run the following command:
```
python3 tools/process_retriever_train_data.py --save retriever_data --data-names TRAIN
```
Train the retriever. The train.jsonl and valid.jsonl data should be put in retriever_data/TRAIN/p1_en1_hn4_s42/merge. The trained retriever can be downloaded from this link.
```
bash scripts/retriever/train.sh ${BASE_PATH}
```

Get encoded paragraphs.

bash scripts/retriever/infer.sh ${BASE_PATH}

Search for paragraphs that share the same intrinsic tasks.
```
bash scripts/retriever/search.sh ${BASE_PATH}
```

4.2 Filter

Filter out non-informative samples.

bash scripts/filter/filter.sh ${BASE_PATH}

5 Pre-train

Pre-train the LM with PICL. The pre-trained models can be downloaded from this link.
```
bash scripts/pretrain/pretrain_picl_gpt2_large.sh ${BASE_PATH}
```

6 Evaluation

Evaluate the trained model on text classification datasets and super-natural instructions. The evaluation data can be downloaded from this link.
```
bash scripts/eval/eval_cls.sh ${BASE_PATH}
bash scripts/eval/eval_inst.sh ${BASE_PATH}
```

7 Citation

@inproceedings{gu2023picl,
  title={Pre-Training to Learn in Context},
  author={Gu, Yuxian and Dong, Li and Wei, Furu and Huang, Minlie},
  booktitle={Proceedings of ACL},
  year={2023}
}