Detailed description

To my knowledge, OpenCV still has no implementation for GpuMats with more than 2 dimensions.
This has been a feature of cv::Mat for a long time, but for some reason it has never been applied to GpuMat, which creates a disconnect when transferring algorithms from CPU implementations to GPU implementations.

This is an example of a cv::Mat function that creates a multi-dimensional matrix:
https://docs.opencv.org/master/d3/d63/classcv_1_1Mat.html#a156df5a1326dd5c30b187b0e721a5f57