Decoding Methods for Neural Narrative Generation

Alexandra DeLucia*, Aaron Mueller*, Xiang "Lisa" Li, João Sedoc

This repository contains code for replicating the approach and results of the paper Decoding Strategies for Neural Narrative Generation.

Models

Our GPT-2 Medium models fine-tuned on the medium and large datasets are available on the library. If you would like the GPT-2 Small model, please reach out to Alexandra DeLucia.

model = AutoModel.from_pretrained("aadelucia/GPT2_medium_narrative_finetuned_medium")

Preprocessing

Our preprocessing script may be found in data/preproc.py. To replicate our setup, download the writingPrompts dataset and unzip the .tar into the data folder. Then run preproc.py.

This script will generate a series of prompts and responses of various lengths. All outputs with the .comb* suffix contain the prompt and response together; .src* files contain only prompts, and .trg* files contain only responses. If there is no number after the suffix, it is the large dataset (full responses). *.1 files are short datasets (1 paragraph), and *.3 files are medium datasets (3 paragraphs). While this script does not impose a token cutoff, we impose a cutoff in the training scripts by thresholding the maximum sequence length.

We also include count_length.py, which calculates the average length of prompt/response pairs per-dataset as well as the total number of tokens per-dataset (replicating the results of our Table 2).

Fine-Tuning

Fine-tuning scripts may be found in the fine-tune folder. Each corresponds to a particular response length. By default, all are configured to fine-tune GPT-2 Medium, though this can be changed by modifying the --model_name_or_path argument.

Generation

The generation script is generate_responses_gpt2med.sh, which calls generate_responses.py to generate the responses from the fine-tuned GPT-2 Medium model on all response lengths (small, medium, large). This script can be used with GPT-2 Small by changing the --model-name-or-path option.

The script was run on the Center for Language and Speech Processing (CLSP) cluster at Johns Hopkins University, where we had access to special features such as "job arrays" ($SGE_TASK_ID).

We include our Maximum Mutual Information (MMI) antiLM generation script (generate_responses_gpt2med_antilm.sh) as well. Note however that this runs on a modified version of the huggingface transformers generation code. We have submitted a pull request to include diverse decoding. You may find our implementation there.

Baseline

We use the fusion model from fairseq. We download and apply their dataset and their trained model. We only modify the generation scripts to generate outputs of different lengths and using different p-values. As p=0 was not a valid hyperparameter, we use a separate script to generate in that case (generate_argmax.sh). These may be found in the baselines folder.

References

If you use the materials in this repository or our models in a research work, please use the following citation:

@misc{delucia2020decoding,
	title={Decoding Methods for Neural Narrative Generation}, 
	author={Alexandra DeLucia and Aaron Mueller and Xiang Lisa Li and João Sedoc},
	year={2020},
	eprint={2010.07375},
	archivePrefix={arXiv},
	primaryClass={cs.CL}
}