Scalable Multi-Output Gaussian Processes with Stochastic Variational Inference
This addresses a scalability bottleneck for researchers and practitioners using MOGPs in domains with many outputs, though it is an incremental improvement over existing LV-MOGP methods.
The paper tackles the computational scalability issue of Latent Variable Multi-Output Gaussian Processes (LV-MOGP) for large numbers of outputs by proposing a stochastic variational inference method that uses mini-batches for inputs and outputs, making per-iteration complexity independent of output count.
The Multi-Output Gaussian Process is is a popular tool for modelling data from multiple sources. A typical choice to build a covariance function for a MOGP is the Linear Model of Coregionalization (LMC) which parametrically models the covariance between outputs. The Latent Variable MOGP (LV-MOGP) generalises this idea by modelling the covariance between outputs using a kernel applied to latent variables, one per output, leading to a flexible MOGP model that allows efficient generalization to new outputs with few data points. Computational complexity in LV-MOGP grows linearly with the number of outputs, which makes it unsuitable for problems with a large number of outputs. In this paper, we propose a stochastic variational inference approach for the LV-MOGP that allows mini-batches for both inputs and outputs, making computational complexity per training iteration independent of the number of outputs.