minnn

by Graham Neubig, Zhisong Zhang, and Divyansh Kaushik

This is an exercise in developing a minimalist neural network toolkit for NLP, part of Carnegie Mellon University's CS11-711: Advanced NLP.

The most important files it contains are the following:

1. minnn.py: This is what you'll need to implement. It implements a very minimalist version of a dynamic neural network toolkit (like PyTorch or Dynet). Some code is provided, but important functionality is not included.
2. classifier.py: training code for a Deep Averaging Network for text classification using minnn. You can feel free to make any modifications to make it a better model. However, the original version of classifier.py will also be tested and results will be used in grading, so the original classifier.py must also run with your minnn.py implementation.
3. setup.py: this is blank, but if your classifier implementation needs to do some sort of data downloading (e.g. of pre-trained word embeddings) you can implement this here. It will be run before running your implementation of classifier.py.
4. data/: Two datasets, one from the Stanford Sentiment Treebank with tree info removed and another from IMDb reviews.

Assignment Details

Important Notes:

• There is a detailed description of the code structure in structure.md, including a description of which parts you will need to implement.
• The only allowed external library is numpy or cupy, no other external libraries are allowed.
• We will run your code with the following commands using both the original classifier.py and your updated classifier.py if you make any modifications there. Because of this, make sure that whichever setting you think is best is reproducible using exactly these commands (where you replace ANDREWID with your andrew ID):
  • mkdir -p ANDREWID
  • python classifier.py --train=data/sst-train.txt --dev=data/sst-dev.txt --test=data/sst-test.txt --dev_out=ANDREWID/sst-dev-output.txt --test_out=ANDREWID/sst-test-output.txt
  • python classifier.py --train=data/cfimdb-train.txt --dev=data/cfimdb-dev.txt --test=data/cfimdb-test.txt --dev_out=ANDREWID/cfimdb-dev-output.txt --test_out=ANDREWID/cfimdb-test-output.txt
• Please remember to set your default hyper-parameter settings in your own classifier.py since we will also run your classifier.py using the above commands (without extra arguments).
• Reference accuracies: with our implementation and the default hyper-parameters, the mean(std) of accuracies with 10 different random seeds on sst is dev=0.4031(0.0105), test=0.4070(0.0114), and on cfimdb dev=0.8980(0.0093). If you implement things exactly in our way and use the default random seed and use the same environment (python 3.8 + numpy 1.18 or 1.19), you may get the accuracies of dev=0.4015, test=0.4109, and on cfimdb dev=0.9020.

The submission file should be a zip file with the following structure (assuming the andrew id is ANDREWID):

• ANDREWID/
• ANDREWID/minnn.py # completed minnn.py
• ANDREWID/classifier.py # completed classifier.py with any of your modifications
• ANDREWID/sst-dev-output.txt # output of the dev set for SST data
• ANDREWID/sst-test-output.txt # output of the test set for SST data
• ANDREWID/cfimdb-dev-output.txt # output of the dev set for CFIMDB data
• ANDREWID/cfimdb-test-output.txt # output of the test set for CFIMDB data
• ANDREWID/report.pdf # (optional), report. here you can describe anything particularly new or interesting that you did

Grading information:

• A+: Submissions that implement something new and achieve particularly large accuracy improvements (for SST, this would be on the order of 2% over the baseline, but you must also achieve gains on IMDB)
• A: You additionally implement something else on top of the missing pieces, some examples include:
  • Implementing another optimizer such as Adam
  • Incorporating pre-trained word embeddings, such as those from fasttext
  • Changing the model architecture significantly
• A-: You implement all the missing pieces and the original classifier.py code achieves comparable accuracy to our reference implementation (about 41% on SST)
• B+: All missing pieces are implemented, but accuracy is not comparable to the reference.
• B or below: Some parts of the missing pieces are not implemented.

Tools:

• There are three tools that may be useful:
• (1) test_minnn.py, can help check for errors in the individual parts of your implementation.
• (2) Using the option of --do_gradient_check 1 when running classifier.py to do gradient checking overall. (Remember to turn this option off in your submitted classifier.py.)
• (3) prepare_submit.py can help to create(1) or check(2) the to-be-submitted zip file. It will throw assertion errors if the format is not expected, and we will not accept submissions that fail this check. Usage: (1) To create and check a zip file with your outputs, run python3 prepare_submit.py path/to/your/output/dir ANDREWID, (2) To check your zip file, run python3 prepare_submit.py path/to/your/submit/zip/file.zip ANDREWID

References

Stanford Sentiment Treebank: https://www.aclweb.org/anthology/D13-1170.pdf

IMDb Reviews: https://openreview.net/pdf?id=Sklgs0NFvr