Variational Gaussian Processes with Signature Covariances

We introduce a Bayesian approach to learn from stream-valued data by using Gaussian processes with the recently introduced signature kernel as covariance function. To cope with the computational complexity in time and memory that arises with long streams that evolve in large state spaces, we develop a variational Bayes approach with sparse inducing tensors. We provide an implementation based on GPFlow and benchmark this variational Gaussian process model on supervised classification tasks for time series and text (a stream of words).