DuelNLG

This repository contains code for evaluating NLG Models as described in the following paper:

Active Evaluation: Efficient NLG Evaluation with Few Pairwise Comparisons
Akash Kumar Mohankumar, Mitesh M. Khapra. Association for Computational Linguistics (ACL), 2022

Table of Contents

• DuelNLG
  • Table of Contents
  • Installation
  • Experiments from Paper
    • Download and Prepare Data
    • Model Free Algorithms
    • Model Based Algorithms

Installation

From Source:

git clone https://github.com/akashkm99/duelnlg.git
cd duelnlg
pip install -e .

To use automatic metrics, you may also need to download nlgeval data:

python ./scripts/download/nlg-eval --setup

Experiments from Paper

Here, we describe the steps to replicate the experiments mentioned in the paper.

Download and Prepare Data

To download and preprocess the WMT 2016 datasets:

bash scripts/preprocess/wmt16.sh

All the processed data will be stored as .pkl files at data/wmt16/processed/

For the WMT 2015 datasets,

bash scripts/preprocess/wmt15.sh

Model Free Algorithms

To perform experiments with model-free dueling bandits algorithms, use the duelnlg/duelpy/experiments/experiments.py script. It has the following arguments:

• --feedback-config: A json config that specifies the list of datasets and their parameters. Use configs/feedback/wmt_all.json to run on all 7 WMT datasets.
• --algorithm-config: Config file that specifies the dueling bandit algorithms and their parameters. Use configs/algorithm/rmed.json to run the RMED algorithm and refer to configs/algorithm/default_all.json for the default parameters for all algorithms.
• --output-dir: Directory to save the results. (Default: ./results/bandits)
• --num-runs: The number of times each algorithm is run with different random seed (Default: 200)
• --random-seed: The base random seed to use (Default: 42)

For example, to run all the dueling bandits algorithm (except: IF and PL which are quite slow) on the WMT 2016 tur->eng dataset with 50 runs use:

python duelnlg/duelpy/experiments/experiments.py \
          --feedback-config ./configs/feedback/wmt16_tur_eng.json \
          --algorithm-config ./configs/algorithm/default_all_no_if_pl.json \
          --num-runs 50 

Model Based Algorithms

1. Download Training and Validation Data

To use direct evaluation metrics, we need to tune a few hyperparameters (e.g. thresholds for the preference probabilities) on a validation set. For training any end-to-end metric for pairwise prediction, we would also require a training set.

To create the train and validation datasets for WMT, we use data from WMT 2013 and 2014:

bash scripts/prepare_train_val/wmt.sh

2. Automatic Evaluation Metrics

To run the Bleurt model, you need to download the model checkpoint:

bash scripts/download/bleurt_ckpt.sh

To run automatic metrics and save the predictions, use the duelnlg/direct_eval/evaluation.py script. It has the following arguments:

• --metrics-config: A json config that specifies the list of automatic metrics and their parameters. Use configs/metrics/bleurt.json to use bleurt and refer to configs/metrics/all.json to run all metrics.
• --val-path and test-path: CSV files with the validation (for tuning) and test datasets. E.g. for WMT 2016, it's ./data/wmt13_14/processed/val.csv and data/wmt16/processed/wmt16-human-judgements.csv respectively.
• --processed-dir: Directory with the processed .pkl files. E.g. for WMT 2016, it's data/wmt16/processed
• --ensemble: Whether to perform mulitple model forward passes with dropout for uncertainity estimation. Applicable only for Bleurt (Default: False)
• --multiref: Whether the dataset has multiple reference texts. (Default: True)

For example, to run the Bleurt metric on WMT 2016 datasets, use the following:

python duelnlg/direct_eval/evaluation.py \
          --metrics ./configs/metrics/bleurt.json \
          --val-path ./data/wmt13_14/processed/val.csv \
          --test-path ./data/wmt16/processed/wmt16-human-judgements.csv \
          --output-results ./results/metrics/bleurt.csv \
          --processed-dir ./data/wmt16/processed

Note:

• Use GPUs to speedup the evaluation. If GPUs are not being used, please check your tensorflow version and CUDA compatibility. (Install a tf (>2.0) version that supports your CUDA version).

• To accelerate your evaluation with Google Cloud TPUs, refer to configs/metrics/bleurt_tpu.json. You just need to provide information on your storage bucket & TPU.

Uncertainity Estimation:

To compute uncertainity in the Bleurt scores (required for Uncertainity-aware selection and UCB elimination algos), use the following:

python duelnlg/direct_eval/evaluation.py \
        --metrics ./configs/metrics/bleurt_ensemble.json \
        --val-path ./data/wmt13_14/processed/val_1k.csv \
        --test-path ./data/wmt16/processed/wmt16-human-judgements.csv \
        --output-results ./results/metrics/bleurt_ensemble.csv \
        --processed-dir ./data/wmt16/processed \
        --ensemble

3. Model Based Dueling Bandits

Once you've computed the automatic metric predictions, you can run model-based algorithms by simply adding the flag --model-config to your duelnlg/duelpy/experiments/experiments.py script.

For example to perform random mixing with Bleurt using RMED on the WMT16 tur->eng dataset, use

python duelnlg/duelpy/experiments/experiments.py \
          --model-config ./configs/models/random_mixing_blerut.json
          --feedback-config ./configs/feedback/wmt16_tur_eng.json \
          --algorithm-config ./configs/algorithm/rmed.json \
          --num-runs 200 

For other model-based algorithms, you can use the following model configs:

| Algorithm | Config | |-------------------------------------|-------------------------------------------------------------| | Random Mixing | ./configs/models/random_mixing_bleurt | | Uncertainity-aware Selection (BALD) | ./configs/models/uncertainity_bleurt.json | | UCB Elimination | ./configs/models/ucb_elimination_bleurt.json | | Uncertainity + UCB Elimination | ./configs/models/uncertainity_ucb_elimination_bleurt.json |