I understand that you are looking for the implementation of Gaussian Process which supports multiple inputs and outputs.
You are correct that the built-in Gaussian Process Regression (GPR) implementation in MATLAB only supports one input and one output. However, there are few other options you can consider that provide a more flexible implementation of the Gaussian Process Regression (GPR).
One of the options which you can use is the GPML (Gaussian Process Machine Learning) Toolbox. This is a popular toolbox that provides a comprehensive set of functions for Gaussian Process models, including multi-input and multi-output GPR.
You can explore the GPML Toolbox and access it through the MATLAB File Exchange by visiting this link:
