The codes were used for the experiments in the paper:

Joo-Kyung Kim, Young-Bum Kim, Ruhi Sarikaya, and Eric Fosler-Lussier, "Cross-lingual Transfer Learning for POS Tagging without Cross-Lingual Resources," EMNLP 2017.

The codes were tested with PyTorch 0.1.12 on Python 3.6. (They are not compatible with Python 2.x but can be migrated easily.)

Refer to files in ud-treebanks-v1.4. Only files for English exist in the repository. The files for other languages can be generated with the following scripts.

chg_corpus_form.py: Change the UD corpus files (https://lindat.mff.cuni.cz/repository/xmlui/handle/11234/1-1827) to the usable formats in the codes.

gen_shuffled_trainset.py: Used to shuffle the trainset file

gen_idxs.py: Generate word, character, and tag index files

main_sepEmbSepTags.py: The main executable file. It has an individual word embedding for each language but shares a label space. Execution example:

./main_sepEmbSepTags.py --tag --tag_acc_flag --lang en_hu

--corpus_dir: the directory containing all the corpus related files (train, dev, test, word_idx, char_idx, and tag_idx)

--lang: Underscore separated languages (e.g., en_hu if using English and Hungarian)

--tag: Sequence tagging

--tag_acc_flag: If True, evaluate with accuracies. If False, with conll script (F1)

--no_shared_rnns: Do not use the shared RNN (Similar to Yang17's model)

--no_sep_rnns: Do not use the separate RNNs (Similar to Jaech16's model)

--rnn_merge_concat: Concat shared RNN outputs and separate RNN outputs. (default is summation)

--utt_enc_type: An utterance is represented as a single vector by 0: sum, 1: mean, 2: CNN w/ avg pooling, 3: CNN w/ max pooling

--dm_adv: 0: nothing, 1: Adversarial training on the shared RNN w/ single (K+1)-ary language classifier, 2: ~~ w/ K binary language classifiers, 3: ~~ w/ K+1 binary classifiers

--recon: bidirectional language modeling

--tag_first_train_mb_cnt, --tag_mid_train_mb_cnt, --tag_last_train_mb_cnt: Limit the number of minibaches, where the POS tag labels will be utilized in the training for the first, those in the middle, or the last language, respectively.

--pivot_weights: Set the weight of the target language to be 1 and set others to keep the relative proportions to be the same

--dm_tag_weights: Weights to the tagging loss

--dm_disc_crit_weights: Set language classifier criterion weights inversely proportional to # minibatches per each language. If False, all the weights are set to 1