Label Models

Lightweight implementations of generative label models for weakly supervised machine learning

Example Usage - Naive Bayes Model

# Let votes be an m x n matrix where m is the number of data examples, n is the
# number of label sources, and each element is in the set {0, 1, ..., k}, where
# k is the number of classes. If votes_{ij} is 0, it means that label source j
# abstains from voting on example i.

# As an example, we create a random votes matrix for binary classification with
# 1000 examples and 5 label sources
import numpy as np
votes = np.random.randint(0, 3, size=(1000, 5))

# We now can create a Naive Bayes generative model to estimate the accuracies
# of these label sources
from labelmodels import NaiveBayes

# We initialize the model by specifying that there are 2 classes (binary
# classification) and 5 label sources
model = NaiveBayes(num_classes=2, num_lfs=5)

# Next, we estimate the model's parameters
model.estimate_label_model(votes)
print(model.get_accuracies())

# We can obtain a posterior distribution over the true labels
labels = model.get_label_distribution(votes)

Example Usage - Partial Label Model

# Let votes be an m x n matrix where m is the number of data examples, n is the
# number of label sources, and each element is in the set {0, 1, ..., k_l}, where
# k_l is the number of label partitions for partial labeling functions PLF_{l}. If votes_{ij} is 0, 
# it means that partial label source j abstains from voting on example i.

# As an example, we create a random votes matrix for classification with
# 1000 examples and 3 label sources
import numpy as np
import torch

# label_partition is a table that specifies 0-indexed PLF's label partition configurations, for this brief example,
# we have 3 PLFs each separating the 3-class label space into two partitions. For 0-th PLF, it partitions the label space
# into \{1\} and \{2,3\}. Notice the class label is 1-indexed.
# The label_partition configures the label partitions mapping in format as {PLF's index: [partition_1, partition_2, ..., partition_{k_l}]}
simple_label_partition = {
        0: [[1], [2, 3]],
        1: [[2], [1, 3]],
        2: [[3], [1, 2]]
}
num_sources = len(simple_label_partition)
num_classes = 3
votes = np.random.randint(0, 1, size=(1000, 3))

device = 'cuda:0' if torch.cuda.is_available() else 'cpu'

# We now can create a Naive Bayes generative model to estimate the accuracies
# of these label sources
from labelmodels import PartialLabelModel
# We initialize the model by specifying that there are 2 classes (binary
# classification) and 5 label sources
model = PartialLabelModel(num_classes=num_classes,
                           label_partition=simple_label_partition,
                           preset_classbalance=None,
                           device=device)
# Next, we estimate the model's parameters
model.estimate_label_model(votes)
print(model.get_accuracies())

# We can obtain a posterior distribution over the true labels
labels = model.get_label_distribution(votes)

Citation

Please cite the following paper if you are using our tool. Thank you!

Esteban Safranchik, Shiying Luo, Stephen H. Bach. "Weakly Supervised Sequence Tagging From Noisy Rules". In 34th AAAI Conference on Artificial Intelligence, 2020.

@inproceedings{safranchik2020weakly,
  title = {Weakly Supervised Sequence Tagging From Noisy Rules}, 
  author = {Safranchik, Esteban and Luo, Shiying and Bach, Stephen H.}, 
  booktitle = {AAAI}, 
  year = 2020, 
}

Peilin Yu, Tiffany Ding , Stephen H. Bach. "Learning from Multiple Noisy Partial Labelers". Artificial Intelligence and Statistics (AISTATS), 2022.

@inproceedings{yu2022nplm,
  title = {Learning from Multiple Noisy Partial Labelers}, 
  author = {Yu, Peilin and Ding, Tiffany and Bach, Stephen H.}, 
  booktitle = {Artificial Intelligence and Statistics (AISTATS)}, 
  year = 2022, 
}