Language Model Zoo

This folder contains scripts for obtaining surprisals from the following pre-trained language models:

1. GRNN
2. JRNN
3. RNNG
4. Transformer-XL
5. Tiny LSTM
6. 5-gram with Kneser-Ney smoothing
7. coming soon: BERT

The models use the following tokenizers:

The parameters are taken from the standard published version of each model unless stated otherwise.

Scripts

Surprisals can be obtained from each model using the script eval_<MODEL>.sh in the scripts folder. Each script expects two arguments: $1 is the input file containing the sentences, and $2 is the output file to save the surprisals.

Input file format

The input file should have each sentence on a new line, and each sentence should be tokenized.

There are also some model-specific constraints, although I may try to streamline these later:

• For every model except RNNG and Tiny LSTM, the sentence should end with an <eos> token.
• The n-gram model is uncased, so you'll have to convert your input file to lowercase to avoid getting unks. I am working on adding a script to do this.
• For RNNG and Tiny LSTM, the input must be unkified. An unkify function is provided in rnng-incremental/get_raw.py, which can be used in the following way:

python2 get_raw.py train.02-21 \
    RAW.txt > UNKIFIED.txt

Output file format

The output file will have the following format:

token1 0.0
token2 ...
.      ...
<eos>  0.0

where the second column (separated by \t) gives the surprisal in bits of the token.

When you run eval_ngram.sh, you will also get an extra .raw output file that has the raw SRILM output with details about word probabilities and backoff.

Dependencies

LSTMs and Transformers

The GRNN, JRNN, Transformer-XL, and Tiny LSTM models require pytorch and other dependencies that can be found in their source folders. If you don't feel like creating your own environments, feel free to "steal" mine: /om2/user/jennhu/conda/envs/neural-nlp (credit to Martin Schrimpf) works for GRNN, JRNN, and Tiny LSTM, and /om2/user/jennhu/conda/envs/transXL was custom-built for Transformer-XL.

RNNG

The dependencies for RNNG should already be set in the source code. If problems arise, I may make a Singularity image available with the relevant C++ libraries.

n-gram

The dependencies for n-gram (SRILM) are also set in a Singularity image called in the script. However, by default, you will also need numpy to convert the raw SRILM output to the standard format. If you don't already have an active conda environment (which has numpy), simply use the command module add openmind/anaconda before running the n-gram script.

Note that I did not add this line to the top of the eval_ngram.sh file because users may want to run the n-gram model in their own preferred environments.

Other tips

When submitting jobs to SLURM, keep in mind that different models have different memory/time requirements. The following settings have worked for me in the past:

The speed is relative to the other models; for reference, Tiny LSTM takes under 1 minute to calculate surprisal for 900 simple sentences (~7 words each), while RNNG takes several hours.

If using GPU, remember to request the appropriate resources in your sbatch call.

I may also add sample SLURM scripts if that would be helpful.

TODO

Adding models

• BERT (currently have working pipeline, but pre-processing is a little more involved)
• action LSTM / stack-only ablated RNNG (Kuncoro et al. 2017) - see Issue #17
• Ordered-Neurons LSTM
• MomLSTM
• PCFG
• add models trained on non-English data

Improving existing models

• add GPU functionality

Ease of use

• add README to each model folder with hyperparameters, etc.
• add script for converting file to lowercase (for n-gram)
• add script for tokenization
• add SLURM script to submit all models as job array
• add environments to shared folder