Build Kokkos as library on target machine or part of code (i.e. in CIME build)

[PeterHjortLauritzen]

What is the feature/what would you like to discuss?

Question for the larger group:

Should we build Kokkos as a library on Derecho and other supported machines (placing the responsibility on the machine maintainers), or should it be part of the StormSPEED source code? (The latter would require the build to be integrated into CIME.)

This version improves clarity and flow. Let me know if further adjustments are needed!

Is there anyone in particular you want to be part of this conversation?

No response

Will this change (regression test) answers?

No

Will you be implementing this enhancement yourself?

Any CAM SE can do this

[sjsprecious]

Based on the discussion with @PeterHjortLauritzen and @jtruesdal today, we think:

1. it is better to begin with the system module of Kokkos on Derecho and make sure everything works as expected.

2. adds the build script of Kokkos into the StormSPEED source code so that a user can choose to build Kokkos from scratch if their machine does not have Kokkos installed.

For the second step, John thinks we may be able to just change the build scripts in the StormSPEED source code so no changes are needed on the CIME's end. The build script used by E3SM can be found at https://github.com/E3SM-Project/E3SM/blob/master/share/build/buildlib.kokkos. We can treat Kokkos as an external library and save it under the libraries folder.