Remove redundant code, refactor large block threshold

platforms/hip/CMakeLists.txt

@@ -22,14 +22,6 @@ ENDIF()
 
 FIND_PACKAGE(HIPFFT CONFIG QUIET)
 
-IF(NOT TARGET hiprtc::hiprtc)
-    add_library(hiprtc::hiprtc SHARED IMPORTED)
-    set_target_properties(hiprtc::hiprtc PROPERTIES
-        IMPORTED_LOCATION "/opt/dtk/hip/lib/libhiprtc.so"
-        INTERFACE_INCLUDE_DIRECTORIES "/opt/dtk/hip/include"
-    )
-ENDIF()
-
 SET(OPENMM_BUILD_HIP_TESTS TRUE CACHE BOOL "Whether to build HIP test cases")
 IF(BUILD_TESTING AND OPENMM_BUILD_HIP_TESTS)
     SUBDIRS(tests)

platforms/hip/src/HipNonbondedUtilities.cpp

@@ -73,7 +73,7 @@ HipNonbondedUtilities::HipNonbondedUtilities(HipContext& context) : context(cont
     // accelerate the process.  This makes building the neighbor list faster, but it prevents
     // us from sorting atom blocks by size, which leads to a slightly less efficient neighbor
     // list.  We guess based on system size which will be faster.
-    useLargeBlocks = false;
+    useLargeBlocks = (context.getNumAtoms() > 150000);
     setKernelSource(HipKernelSources::nonbonded);
 }