This is the implementation of the Kernel-based Neural Ranking Model (K-NRM) model from paper End-to-End Neural Ad-hoc Ranking with Kernel Pooling.

If you use this code for your scientific work, please cite it as (bibtex):

C. Xiong, Z. Dai, J. Callan, Z. Liu, and R. Power. End-to-end neural ad-hoc ranking with kernel pooling. 
In Proceedings of the 40th International ACM SIGIR Conference on Research & Development in Information Retrieval. 
ACM. 2017.

• Tensorflow 0.12
• Numpy
• traitlets

Coming soon: K-NRM with Tensorflow 1.0

Configure: first, configure the model through the config file. Configurable parameters are listed here

sample.config

Training : pass the config file, training data and validation data as

python ./knrm/model/model_knrm.py config-file\
    --train \
    --train_file: path to training data\
    --validation_file: path to validation data\
    --train_size: size of training data (number of training samples)\
    --checkpoint_dir: directory to store/load model checkpoints\ 
    --load_model: True or False. Start with a new model or continue training

sample-train.sh

Testing: pass the config file and testing data as

python ./knrm/model/model_knrm.py config-file\
    --test \
    --test_file: path to testing data\
    --test_size: size of testing data (number of testing samples)\
    --checkpoint_dir: directory to load trained model\
    --output_score_file: file to output documents score\

Relevance scores will be output to output_score_file, one score per line, in the same order as test_file. We provide a script to convert scores into trec format.

./knrm/tools/gen_trec_from_score.py

All queries and documents must be mapped into sequences of integer term ids. Term id starts with 1. -1 indicates OOV or non-existence. Term ids are sepereated by ,

Training Data Format

Each training sample is a tuple of (query, postive document, negative document)

query \t postive_document \t negative_document \t score_difference

Example: 177,705,632 \t 177,705,632,-1,2452,6,98 \t 177,705,632,3,25,14,37,2,146,159, -1 \t 0.119048

If score_difference < 0, the data generator will swap postive docment and negative document.

If score_difference < lickDataGenerator.min_score_diff, this training sample will be omitted.

We recommend shuffling the training samples to ease model convergence.

Testing Data Format

Each testing sample is a tuple of (query, document)

q \t document

Example: 177,705,632 \t 177,705,632,-1,2452,6,98

Model Configurations

• BaseNN.n_bins: number of kernels (soft bins) (default: 11. One exact match kernel and 10 soft kernels)
• Knrm.lamb: defines the guassian kernels' sigma value. sigma = lamb * bin_size (default:0.5 -> sigma=0.1)
• BaseNN.embedding_size: embedding dimension (default: 300)
• BaseNN.max_q_len: max query length (default: 10)
• BaseNN.max_d_len: max document length (default: 50)
• DataGenerator.max_q_len: max query length. Should be the same as BaseNN.max_q_len (default: 10)
• DataGenerator.max_d_len: max query length. Should be the same as BaseNN.max_d_len (default: 50)
• BaseNN.vocabulary_size: vocabulary size.
• DataGenerator.vocabulary_size: vocabulary size.

Data

• Knrm.emb_in: initial embeddings
• DataGenerator.min_score_diff: minimum score differences between postive documents and negative ones (default: 0)

Training Parameters

• BaseNN.bath_size: batch size (default: 16)
• BaseNN.max_epochs: max number of epochs to train
• BaseNN.eval_frequency: evaluate model on validation set very this steps (default: 1000)
• BaseNN.checkpoint_steps: save model very this steps (default: 10000)
• Knrm.learning_rate: learning rate for Adam Opitmizer (default: 0.001)
• Knrm.epsilon: epsilon for Adam Optimizer (default: 0.00001)

During training, it takes about 60ms to process one batch on a single-GPU machine with the following settings:

• batch size: 16
• max_q_len: 10
• max_d_len: 50
• vocabulary_size: 300K

Smaller vocabulary and shorter documents accelerate the training.

We also provide the click2vec model as described in our paper.

• ./knrm/click2vec/generate_click_term_pair.py: generate <query_term, clicked_title_term> pairs
• ./knrm/click2vec/run_word2vec.sh: call Google's word2vec tool to train click2vec.

If you use this code for your scientific work, please cite it as:

C. Xiong, Z. Dai, J. Callan, Z. Liu, and R. Power. End-to-end neural ad-hoc ranking with kernel pooling. 
In Proceedings of the 40th International ACM SIGIR Conference on Research & Development in Information Retrieval. 
ACM. 2017.

@inproceedings{xiong2017neural,
  author          = {{Xiong}, Chenyan and {Dai}, Zhuyun and {Callan}, Jamie and {Liu}, Zhiyuan and {Power}, Russell},
  title           = "{End-to-End Neural Ad-hoc Ranking with Kernel Pooling}",
  booktitle       = {Proceedings of the 40th International ACM SIGIR Conference on Research & Development in Information Retrieval},
  organization    = {ACM},
  year            = 2017,
}