Implements the mutual information estimation algorithm and scaling analysis carried out in Mutual Information Scaling for Tensor Network Machine Learning (2022). The abstract of the paper is reproduced here:
Tensor networks have emerged as promising tools for machine learning, inspired by their widespread use as variational ansatze in quantum many-body physics. It is well known that the success of a given tensor network ansatz depends in part on how well it can reproduce the underlying entanglement structure of the target state, with different network designs favoring different scaling patterns. We demonstrate here how a related correlation analysis can be applied to tensor network machine learning, and explore whether classical data possess correlation scaling patterns similar to those found in quantum states which might indicate the best network to use for a given dataset. We utilize mutual information as a measure of correlations in classical data, and show that it can serve as a lower-bound on the entanglement needed for a probabilistic tensor network classifier. We then develop a logistic regression algorithm to estimate the mutual information between bipartitions of data features, and verify its accuracy on a set of Gaussian distributions designed to mimic different correlation patterns. Using this algorithm, we characterize the scaling patterns in the MNIST and Tiny Images datasets, and find clear evidence of boundary-law scaling in the latter. This quantum-inspired classical analysis offers insight into the design of tensor networks which are best suited for specific learning tasks.
In the Jupyter notebook examples.ipynb a summary of the work is presented, along with a portion of the experiments used to generate the paper's numerical results. The full source code is given in the src folder, although it is missing some of the large data files that are needed for all portions of the code to run.
A non-interactive write-up of the project can be found on my website.