Invalid `rot_source_type` is not handled on GPU, leaving rotation energy source uninitialized

Summary

Both rsrc() and corrrsrc() guard the invalid-rot_source_type error with #ifndef AMREX_USE_GPU. On GPU builds, invalid values skip the error path and proceed with uninitialized SrE / SrEcorr, contaminating UEDEN source terms.

Location

• Source/rotation/rotation_sources.cpp:117
• Source/rotation/rotation_sources.cpp:433

Problem Details

Current pattern:

} else {
#ifndef AMREX_USE_GPU
  amrex::Error("... invalid rot_source_type");
#endif
}

src[UEDEN] += SrE;      // or src[UEDEN] = SrEcorr;

On GPU, the else body does nothing and the code uses undefined values.

Impact

• Undefined behavior and non-physical energy updates when rot_source_type is misconfigured.
• Silent corruption in GPU runs instead of a clear fatal error.

Suggested Patch

Make invalid configuration fatal in all builds:

diff --git a/Source/rotation/rotation_sources.cpp b/Source/rotation/rotation_sources.cpp
--- a/Source/rotation/rotation_sources.cpp
+++ b/Source/rotation/rotation_sources.cpp
@@
     } else {
-#ifndef AMREX_USE_GPU
       amrex::Error("Error:: rotation_sources_nd.F90 :: invalid rot_source_type");
-#endif
     }
@@
     } else {
-#ifndef AMREX_USE_GPU
       amrex::Error("Error:: rotation_sources_nd.F90 :: invalid rot_source_type");
-#endif
     }

Prepared by Codex

Start in Source/rotation/rotation_sources.cpp at lines 117 and 433, reviewing the invalid rot_source_type branches in rsrc() and corrrsrc(). Check the CPU and GPU build behavior, then verify that invalid configuration cannot reach the UEDEN updates with uninitialized rotation energy sources.