I followed what was done in other packages and added CudaPackage second.

class PyTorch(PythonPackage, CudaPackage):

However, I think that makes the base class CudaPackage. I wonder if this should be

class PyTorch(CudaPackage, PythonPackage):

instead. That would affect the following packages:

• accfft
• amber
• ascent
• bohrium
• cp2k
• dealii
• ghost
• ginkgo
• hpx
• lammps
• libbeagle
• megadock
• opencv
• paraview
• qmcpack
• relion
• rodinia
• sirius
• xgboost
• gpu-burn
• py-tensorflow
• vtk-h
• vtk-m

@glennpj what makes you think the base class is CudaPackage? When I run spack info py-torch it correctly says the base class is PythonPackage.

I am thinking of inheritance order. It probably would never matter, and I could be thinking about it incorrectly, but if we wanted to have the PythonPackage class override something defined in the CudaPackage class I think the order might need to be reversed.