Torch grid_sample coordinates transposed issue

[EdwardFerdian]

Hi @MalikTeng,

There is a potential issue with the F.grid_sample as it receives a ZYX ordered coordinate system instead of XYZ.
This was discussed here: https://discuss.pytorch.org/t/surprising-convention-for-grid-sample-coordinates/79997/9

You may need to transpose the coordinates first before performing the sampling.
It will have impact with the feature sampling (for the graph vertices) and learning process of the network in general.

[MalikTeng]

Hi @EdwardFerdian,

Much appreciate your input! I'll update the code and do some recheck on the experiments, to see if this can make the model training process more steady.