CMake: Decouple ELPA dependency from LCAO

Author: Growl1234

CMakeLists.txt

@@ -65,7 +65,7 @@ option(ENABLE_RAPIDJSON "Enable rapid-json usage" OFF)
 option(ENABLE_CNPY "Enable cnpy usage" OFF)
 
 # Options requiring MPI and LCAO
-cmake_dependent_option(ENABLE_ELPA "Enable ELPA for LCAO" ON "ENABLE_LCAO;ENABLE_MPI" OFF)
+cmake_dependent_option(ENABLE_ELPA "Enable ELPA eigensolver" ON "ENABLE_MPI" OFF)
 cmake_dependent_option(ENABLE_LIBRI "Enable LibRI for hybrid functional"
                        OFF "ENABLE_LCAO;ENABLE_MPI" OFF)
 cmake_dependent_option(ENABLE_PEXSI "Enable PEXSI for LCAO" OFF "ENABLE_LCAO;ENABLE_MPI" OFF)
@@ -304,17 +304,15 @@ if(CMAKE_CXX_COMPILER_ID MATCHES Intel)
   set(ENABLE_ABACUS_LIBM OFF)
 endif()
 
-if(ENABLE_LCAO)
-  if(ENABLE_ELPA)
-    find_package(ELPA REQUIRED)
-  endif()
-  if(ENABLE_PEXSI)
-    find_package(PEXSI REQUIRED CONFIG)
-    if(PEXSI_VERSION VERSION_LESS "2.0.0")
-      message(FATAL_ERROR "PEXSI >= 2.0.0 is required")
-    endif()
-    set(CMAKE_CXX_STANDARD 14)
+if(ENABLE_ELPA)
+  find_package(ELPA REQUIRED)
+endif()
+if(ENABLE_PEXSI)
+  find_package(PEXSI REQUIRED CONFIG)
+  if(PEXSI_VERSION VERSION_LESS "2.0.0")
+    message(FATAL_ERROR "PEXSI >= 2.0.0 is required")
   endif()
+  set(CMAKE_CXX_STANDARD 14)
 endif()
 
 if(ENABLE_MPI)