No description, website, or topics provided.
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.



We address the problem of multi-class classification in the case where the number of classes is very large. We propose a double sampling strategy on top of a multi-class to binary reduction strategy, which transforms the original multi-class problem into a binary classification problem over pairs of examples. The aim of the sampling strategy is to overcome the curse of long-tailed class distributions exhibited in majority of large-scale multi-class classification problems and to reduce the number of pairs of examples in the expanded data. Experiments are carried out on DMOZ and Wikipedia collections with 10,000 to 100,000 classes where we show the efficiency of the proposed approach in terms of training and prediction time, memory consumption, and predictive performance with respect to state-of-the-art approaches.

Running Instructions:

python3 [train filename] [test filename] [example_samples] [class_sampling_rate] [Candidates]


example_samples (mu): Average number of examples sampled per class. The examples are chosen at random from each class with probability based on the distribution. ( e.g. values 1, 2, 5, 10)

class_sampling_rate: Sampling rate for choosing classes to sample ( e.g. 0.1, 0.01, 0.001) (Note: The minimum value for class_ sampling is set as 1 / Size of class, if user enters less than this value by default 1 class will be chosen.

Candidates (sigma): Number of candidate classes for prediction (e.g. 10, 25, 50)

Link to Datasets:

Author Information:

1.) Bikash Joshi

2.) Ioannis Partalas


This software is licensed under GNU General Public License version 3.0


If you publish results using this program, please acknowledge its use, by referring to:

Joshi B., Amini M.-R., Partalas I., Iutzeler F., Maximov Y. Aggressive Sampling for Multi-class to Binary Reduction with Applications to Text Classification Advances in Neural Information Processing Systems 30 (NIPS 2017), p. 4162-4171