Sparse Tensor Classifier

Sparse Tensor Classifier (STC) is a supervised classification algorithm for categorical data inspired by the notion of superposition of states in quantum physics. It supports multiclass and multilabel classification, online learning, prior knowledge, automatic dataset balancing, missing data, and provides a native explanation of its predictions both for single instances and for each target class label globally. Read more at

The algorithm is implemented in SQL and made available via the Python module stc on PyPI. By default, the library uses an in-memory SQLite database, shipped with Python standard library, that require no configuration by the user. It is also possible to configure STC to run on alternative DBMS in order to take advantage of persistent storage and scalability.


Install stc from PyPI. We recommend using Python>=3.7 and SQLite>=3.24.0 for better performance.

pip install stc


Initialize, fit, and predict. Get started in 3 lines on code!

Example: use Sparse Tensor Classifier to classify animals. The dataset consists of 101 animals from a zoo. There are 16 variables with various traits to describe the animals. The 7 Class Types are: Mammal, Bird, Reptile, Fish, Amphibian, Bug and Invertebrate. The purpose for this dataset is to be able to predict the classification of the animals. STC returns a tuple with (1) the predicted classes, (2) the probability for each class, and (3) the contribution of each feature to the target class labels (explainability).

import pandas as pd
from stc import SparseTensorClassifier

# Read the dataset
zoo = pd.read_csv('')
# Initialize the class
STC = SparseTensorClassifier(targets=['class_type'], features=zoo.columns[1:-1])
# Fit the training data[0:70])
# Predict the test data
labels, probability, explainability = STC.predict(zoo[70:])


Discover the flexibility of the library in the documentation.


Get started with step-by-step tutorials and use-cases.

Bug Reports

Open an issue on GitHub.

Cite as

Guidotti E., Ferrara A., (2021). “An Explainable Probabilistic Classifier for Categorical Data Inspired to Quantum Physics” arXiv:2105.13988

See references


All code is released under the GNU GPL-3. If you need to use the same code under different terms, for instance allowing its inclusion in proprietary applications, contact us to obtain an exception.