From e6ebf077fb7de147eb6e3d4b9935b22a276dfdcc Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Fri, 12 Jan 2024 20:17:53 +0800
Subject: [PATCH 01/15] Fix for finding LibXC and ELPA

---
 CMakeLists.txt        | 11 +++++-----
 cmake/FindELPA.cmake  | 50 +++++++++++++++++++++++++++----------------
 cmake/FindLibxc.cmake | 43 +++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 23 deletions(-)
 create mode 100644 cmake/FindLibxc.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 431f844993..19bd7adeb4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -508,11 +508,12 @@ if(DEFINED Libxc_DIR)
   set(ENABLE_LIBXC ON)
 endif()
 if(ENABLE_LIBXC)
-  find_package(Libxc REQUIRED HINTS
-    ${Libxc_DIR}/share/cmake/Libxc
-    ${Libxc_DIR}/lib/cmake/Libxc
-    ${Libxc_DIR}/lib64/cmake/Libxc
-  )
+#  find_package(Libxc REQUIRED HINTS
+#    ${Libxc_DIR}/share/cmake/Libxc
+#    ${Libxc_DIR}/lib/cmake/Libxc
+#    ${Libxc_DIR}/lib64/cmake/Libxc
+#  )
+  find_package(Libxc REQUIRED)
   message(STATUS "Found Libxc: version " ${Libxc_VERSION})
   if(${Libxc_VERSION} VERSION_LESS 5.1.7)
     message(FATAL_ERROR "LibXC >= 5.1.7 is required.")
diff --git a/cmake/FindELPA.cmake b/cmake/FindELPA.cmake
index 5769f7248c..8606490a6e 100644
--- a/cmake/FindELPA.cmake
+++ b/cmake/FindELPA.cmake
@@ -7,23 +7,37 @@
 #  ELPA_INCLUDE_DIR - Where to find ELPA headers.
 #
 
-find_path(ELPA_INCLUDE_DIR
-    elpa/elpa.h
-    HINTS ${ELPA_DIR}
-    PATH_SUFFIXES "include" "include/elpa"
-    )
-if(USE_OPENMP)
-    find_library(ELPA_LIBRARY
-        NAMES elpa_openmp elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
+# Legacy Routine
+#find_path(ELPA_INCLUDE_DIR
+#    elpa/elpa.h
+#    HINTS ${ELPA_DIR}
+#    PATH_SUFFIXES "include" "include/elpa"
+#    )
+#if(USE_OPENMP)
+#    find_library(ELPA_LIBRARY
+#        NAMES elpa_openmp elpa
+#        HINTS ${ELPA_DIR}
+#        PATH_SUFFIXES "lib"
+#        )
+#else()
+#    find_library(ELPA_LIBRARY
+#        NAMES elpa
+#        HINTS ${ELPA_DIR}
+#        PATH_SUFFIXES "lib"
+#        )
+#endif()
+
+find_package(PkgConfig)
+
+if(PKG_CONFIG_FOUND)
+        if(USE_OPENMP)
+    pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa_openmp)
+  else()
+    pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa)
+  endif()
 else()
-    find_library(ELPA_LIBRARY
-        NAMES elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
+  message(
+    "ELPA : We need pkg-config to get all information about the elpa library")
 endif()
 
 # Handle the QUIET and REQUIRED arguments and
@@ -33,8 +47,8 @@ find_package_handle_standard_args(ELPA DEFAULT_MSG ELPA_LIBRARY ELPA_INCLUDE_DIR
 
 # Copy the results to the output variables and target.
 if(ELPA_FOUND)
-    set(ELPA_LIBRARIES ${ELPA_LIBRARY})
-    set(ELPA_INCLUDE_DIR ${ELPA_INCLUDE_DIR})
+    set(ELPA_LIBRARY ${ELPA_LIBRARIES})
+    set(ELPA_INCLUDE_DIR ${ELPA_INCLUDE_DIRS})
 
     if(NOT TARGET ELPA::ELPA)
         add_library(ELPA::ELPA UNKNOWN IMPORTED)
diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
new file mode 100644
index 0000000000..4446b2e7da
--- /dev/null
+++ b/cmake/FindLibxc.cmake
@@ -0,0 +1,43 @@
+###############################################################################
+# - Find ELPA
+# Find the native ELPA headers and libraries.
+#
+#  ELPA_FOUND        - True if libelpa is found.
+#  ELPA_LIBRARIES    - List of libraries when using libyaml
+#  ELPA_INCLUDE_DIR - Where to find ELPA headers.
+#
+
+#find_path(ELPA_INCLUDE_DIR
+#    elpa/elpa.h
+#    HINTS ${ELPA_DIR}
+#    PATH_SUFFIXES "include" "include/elpa"
+#    )
+
+find_package(PkgConfig)
+
+if(PKG_CONFIG_FOUND)
+	pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
+else()
+  message(
+	  "LibXC : We need pkg-config to get all information about the libxc library")
+endif()
+
+# Handle the QUIET and REQUIRED arguments and
+# set ELPA_FOUND to TRUE if all variables are non-zero.
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
+
+# Copy the results to the output variables and target.
+if(Libxc_FOUND AND NOT TARGET Libxc::xc)
+	set(Libxc_LIBRARY ${Libxc_LINK_LIBRARIES})
+	set(Libxc_LIBRARIES ${Libxc_LIBRARY})
+	set(Libxc_INCLUDE_DIR ${Libxc_INCLUDE_DIRS})
+	add_library(Libxc::xc UNKNOWN IMPORTED)
+	set_target_properties(Libxc::xc PROPERTIES
+		IMPORTED_LOCATION "${Libxc_LIBRARY}"
+		INTERFACE_INCLUDE_DIRECTORIES "${Libxc_INCLUDE_DIR}")
+endif()
+
+set(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES} ${Libxc_INCLUDE_DIR})
+
+mark_as_advanced(Libxc_INCLUDE_DIR Libxc_LIBRARY)

From b43112b1f38b30cf707b0580da6463e9addc2558 Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Fri, 12 Jan 2024 20:49:24 +0800
Subject: [PATCH 02/15] For compatibility to previous routines

---
 cmake/FindELPA.cmake  | 63 +++++++++++++++++++++++++++----------------
 cmake/FindLibxc.cmake | 19 +++++++------
 2 files changed, 51 insertions(+), 31 deletions(-)

diff --git a/cmake/FindELPA.cmake b/cmake/FindELPA.cmake
index 8606490a6e..2200d43dc1 100644
--- a/cmake/FindELPA.cmake
+++ b/cmake/FindELPA.cmake
@@ -7,25 +7,24 @@
 #  ELPA_INCLUDE_DIR - Where to find ELPA headers.
 #
 
-# Legacy Routine
-#find_path(ELPA_INCLUDE_DIR
-#    elpa/elpa.h
-#    HINTS ${ELPA_DIR}
-#    PATH_SUFFIXES "include" "include/elpa"
-#    )
-#if(USE_OPENMP)
-#    find_library(ELPA_LIBRARY
-#        NAMES elpa_openmp elpa
-#        HINTS ${ELPA_DIR}
-#        PATH_SUFFIXES "lib"
-#        )
-#else()
-#    find_library(ELPA_LIBRARY
-#        NAMES elpa
-#        HINTS ${ELPA_DIR}
-#        PATH_SUFFIXES "lib"
-#        )
-#endif()
+find_path(ELPA_INCLUDE_DIR
+    elpa/elpa.h
+    HINTS ${ELPA_DIR}
+    PATH_SUFFIXES "include" "include/elpa"
+    )
+if(USE_OPENMP)
+    find_library(ELPA_LIBRARY
+        NAMES elpa_openmp elpa
+        HINTS ${ELPA_DIR}
+        PATH_SUFFIXES "lib"
+        )
+else()
+    find_library(ELPA_LIBRARY
+        NAMES elpa
+        HINTS ${ELPA_DIR}
+        PATH_SUFFIXES "lib"
+        )
+endif()
 
 find_package(PkgConfig)
 
@@ -36,18 +35,36 @@ if(PKG_CONFIG_FOUND)
     pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa)
   endif()
 else()
-  message(
-    "ELPA : We need pkg-config to get all information about the elpa library")
+  find_path(ELPA_INCLUDE_DIRS
+    elpa/elpa.h
+    HINTS ${ELPA_DIR}
+    PATH_SUFFIXES "include" "include/elpa"
+    )
+  if(USE_OPENMP)
+	  find_library(ELPA_LINK_LIBRARIES
+        NAMES elpa_openmp elpa
+        HINTS ${ELPA_DIR}
+        PATH_SUFFIXES "lib"
+        )
+  else()
+	  find_library(ELPA_LINK_LIBRARIES
+        NAMES elpa
+        HINTS ${ELPA_DIR}
+        PATH_SUFFIXES "lib"
+        )
+  endif()
+  #message(
+  #  "ELPA : We need pkg-config to get all information about the elpa library")
 endif()
 
 # Handle the QUIET and REQUIRED arguments and
 # set ELPA_FOUND to TRUE if all variables are non-zero.
 include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(ELPA DEFAULT_MSG ELPA_LIBRARY ELPA_INCLUDE_DIR)
+find_package_handle_standard_args(ELPA DEFAULT_MSG ELPA_LINK_LIBRARIES ELPA_INCLUDE_DIRS)
 
 # Copy the results to the output variables and target.
 if(ELPA_FOUND)
-    set(ELPA_LIBRARY ${ELPA_LIBRARIES})
+    set(ELPA_LIBRARY ${ELPA_LINK_LIBRARIES})
     set(ELPA_INCLUDE_DIR ${ELPA_INCLUDE_DIRS})
 
     if(NOT TARGET ELPA::ELPA)
diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 4446b2e7da..23f8689e27 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -13,20 +13,23 @@
 #    PATH_SUFFIXES "include" "include/elpa"
 #    )
 
+include(FindPackageHandleStandardArgs)
+
 find_package(PkgConfig)
 
 if(PKG_CONFIG_FOUND)
-	pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
+  pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
+  find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
 else()
-  message(
-	  "LibXC : We need pkg-config to get all information about the libxc library")
+  find_package(Libxc REQUIRED HINTS
+    ${Libxc_DIR}/share/cmake/Libxc
+    ${Libxc_DIR}/lib/cmake/Libxc
+    ${Libxc_DIR}/lib64/cmake/Libxc
+  )
+  #message(
+  #	  "LibXC : We need pkg-config to get all information about the libxc library")
 endif()
 
-# Handle the QUIET and REQUIRED arguments and
-# set ELPA_FOUND to TRUE if all variables are non-zero.
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
-
 # Copy the results to the output variables and target.
 if(Libxc_FOUND AND NOT TARGET Libxc::xc)
 	set(Libxc_LIBRARY ${Libxc_LINK_LIBRARIES})

From e8d46c447d62be2c0270b5274088fbed1470cd60 Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Fri, 12 Jan 2024 21:04:40 +0800
Subject: [PATCH 03/15] syntax fix for FindELPA.cmake

---
 cmake/FindELPA.cmake | 39 ++++++++++-----------------------------
 1 file changed, 10 insertions(+), 29 deletions(-)

diff --git a/cmake/FindELPA.cmake b/cmake/FindELPA.cmake
index 2200d43dc1..a6f5663c22 100644
--- a/cmake/FindELPA.cmake
+++ b/cmake/FindELPA.cmake
@@ -7,25 +7,6 @@
 #  ELPA_INCLUDE_DIR - Where to find ELPA headers.
 #
 
-find_path(ELPA_INCLUDE_DIR
-    elpa/elpa.h
-    HINTS ${ELPA_DIR}
-    PATH_SUFFIXES "include" "include/elpa"
-    )
-if(USE_OPENMP)
-    find_library(ELPA_LIBRARY
-        NAMES elpa_openmp elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
-else()
-    find_library(ELPA_LIBRARY
-        NAMES elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
-endif()
-
 find_package(PkgConfig)
 
 if(PKG_CONFIG_FOUND)
@@ -41,17 +22,17 @@ else()
     PATH_SUFFIXES "include" "include/elpa"
     )
   if(USE_OPENMP)
-	  find_library(ELPA_LINK_LIBRARIES
-        NAMES elpa_openmp elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
+    find_library(ELPA_LINK_LIBRARIES
+      NAMES elpa_openmp elpa
+      HINTS ${ELPA_DIR}
+      PATH_SUFFIXES "lib"
+      )
   else()
-	  find_library(ELPA_LINK_LIBRARIES
-        NAMES elpa
-        HINTS ${ELPA_DIR}
-        PATH_SUFFIXES "lib"
-        )
+    find_library(ELPA_LINK_LIBRARIES
+      NAMES elpa
+      HINTS ${ELPA_DIR}
+      PATH_SUFFIXES "lib"
+      )
   endif()
   #message(
   #  "ELPA : We need pkg-config to get all information about the elpa library")

From 283b67fe1efb7d501404339f4f1fc24535f4b29b Mon Sep 17 00:00:00 2001
From: YI Zeping <18586016708@163.com>
Date: Mon, 15 Jan 2024 14:21:29 +0800
Subject: [PATCH 04/15] Update cmake/FindELPA.cmake

Co-authored-by: Chun Cai <amoycaic@gmail.com>
---
 cmake/FindELPA.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/FindELPA.cmake b/cmake/FindELPA.cmake
index a6f5663c22..ec539d8b81 100644
--- a/cmake/FindELPA.cmake
+++ b/cmake/FindELPA.cmake
@@ -10,7 +10,7 @@
 find_package(PkgConfig)
 
 if(PKG_CONFIG_FOUND)
-        if(USE_OPENMP)
+  if(USE_OPENMP)
     pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa_openmp)
   else()
     pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa)

From f9e3642d621939aafbcc2a98f1ee70859467dc1a Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Mon, 15 Jan 2024 15:04:11 +0800
Subject: [PATCH 05/15] Using CMake interface as default for finding LibXC

---
 cmake/FindLibxc.cmake | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 23f8689e27..1bccd7f113 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -17,20 +17,22 @@ include(FindPackageHandleStandardArgs)
 
 find_package(PkgConfig)
 
-if(PKG_CONFIG_FOUND)
-  pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
-  find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
-else()
-  find_package(Libxc REQUIRED HINTS
+# Using CMake interface as default.
+# NO REQUIRED here, otherwhile it would throw error
+# with no LibXC found.
+find_package(Libxc HINTS
     ${Libxc_DIR}/share/cmake/Libxc
     ${Libxc_DIR}/lib/cmake/Libxc
     ${Libxc_DIR}/lib64/cmake/Libxc
   )
-  #message(
-  #	  "LibXC : We need pkg-config to get all information about the libxc library")
+if(NOT Libxc_FOUND AND PKG_CONFIG_FOUND)
+  pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
+  find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
 endif()
 
 # Copy the results to the output variables and target.
+# if find_package() above works, Libxc::xc would be present and
+# below would be skipped.
 if(Libxc_FOUND AND NOT TARGET Libxc::xc)
 	set(Libxc_LIBRARY ${Libxc_LINK_LIBRARIES})
 	set(Libxc_LIBRARIES ${Libxc_LIBRARY})
@@ -39,6 +41,9 @@ if(Libxc_FOUND AND NOT TARGET Libxc::xc)
 	set_target_properties(Libxc::xc PROPERTIES
 		IMPORTED_LOCATION "${Libxc_LIBRARY}"
 		INTERFACE_INCLUDE_DIRECTORIES "${Libxc_INCLUDE_DIR}")
+elseif(NOT Libxc_FOUND)
+  message(FATAL_ERROR
+          "LibXC : We need pkg-config to get all information about the libxc library")
 endif()
 
 set(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES} ${Libxc_INCLUDE_DIR})

From 660d3906fa95b1a234463a34111c057dd24af5dd Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Mon, 15 Jan 2024 15:47:00 +0800
Subject: [PATCH 06/15] update docs

---
 cmake/FindELPA.cmake             | 3 +++
 cmake/FindLibxc.cmake            | 9 ++++++---
 docs/quick_start/easy_install.md | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/cmake/FindELPA.cmake b/cmake/FindELPA.cmake
index ec539d8b81..328b75035f 100644
--- a/cmake/FindELPA.cmake
+++ b/cmake/FindELPA.cmake
@@ -10,6 +10,9 @@
 find_package(PkgConfig)
 
 if(PKG_CONFIG_FOUND)
+  if(DEFINED ELPA_DIR)
+    string(APPEND CMAKE_PREFIX_PATH ";${ELPA_DIR}")
+  endif()
   if(USE_OPENMP)
     pkg_search_module(ELPA REQUIRED IMPORTED_TARGET GLOBAL elpa_openmp)
   else()
diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 1bccd7f113..74348a5adc 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -17,6 +17,9 @@ include(FindPackageHandleStandardArgs)
 
 find_package(PkgConfig)
 
+if(DEFINED Libxc_DIR)
+  string(APPEND CMAKE_PREFIX_PATH ";${Libxc_DIR}")
+endif()
 # Using CMake interface as default.
 # NO REQUIRED here, otherwhile it would throw error
 # with no LibXC found.
@@ -28,6 +31,9 @@ find_package(Libxc HINTS
 if(NOT Libxc_FOUND AND PKG_CONFIG_FOUND)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
   find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
+elseif(NOT PKG_CONFIG_FOUND)
+  message(FATAL_ERROR
+          "LibXC : We need pkg-config to get all information about the libxc library")
 endif()
 
 # Copy the results to the output variables and target.
@@ -41,9 +47,6 @@ if(Libxc_FOUND AND NOT TARGET Libxc::xc)
 	set_target_properties(Libxc::xc PROPERTIES
 		IMPORTED_LOCATION "${Libxc_LIBRARY}"
 		INTERFACE_INCLUDE_DIRECTORIES "${Libxc_INCLUDE_DIR}")
-elseif(NOT Libxc_FOUND)
-  message(FATAL_ERROR
-          "LibXC : We need pkg-config to get all information about the libxc library")
 endif()
 
 set(CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES} ${Libxc_INCLUDE_DIR})
diff --git a/docs/quick_start/easy_install.md b/docs/quick_start/easy_install.md
index 957b9d3262..4bb409495b 100644
--- a/docs/quick_start/easy_install.md
+++ b/docs/quick_start/easy_install.md
@@ -111,7 +111,7 @@ Here, 'build' is the path for building ABACUS; and '-D' is used for setting up s
   - `LAPACK_DIR`: Path to OpenBLAS library `libopenblas.so`(including BLAS and LAPACK)
   - `SCALAPACK_DIR`: Path to ScaLAPACK library `libscalapack.so`
   - `ELPA_DIR`: Path to ELPA install directory; should be the folder containing 'include' and 'lib'.
-  > Note: If you install ELPA from source, please add a symlink to avoid the additional include file folder with version name: `ln -s elpa/include/elpa-2021.05.002/elpa elpa/include/elpa`. This is a known behavior of ELPA.
+  > Note: If you install ELPA from source and have no `pkg-config` installed, please add a symlink to avoid the additional include file folder with version name: `ln -s elpa/include/elpa-2021.05.002/elpa elpa/include/elpa` to help the build system find ELPA headers.
 
   - `FFTW3_DIR`: Path to FFTW3.
   - `CEREAL_INCLUDE_DIR`: Path to the parent folder of `cereal/cereal.hpp`. Will download from GitHub if absent.

From 7bd18db5e4e5ceba44857857d4d2206aac29e933 Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Mon, 15 Jan 2024 15:51:05 +0800
Subject: [PATCH 07/15] fix for FindLibxc: changing imcompatible if statement

---
 cmake/FindLibxc.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 74348a5adc..0d438a8583 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -28,7 +28,7 @@ find_package(Libxc HINTS
     ${Libxc_DIR}/lib/cmake/Libxc
     ${Libxc_DIR}/lib64/cmake/Libxc
   )
-if(NOT Libxc_FOUND AND PKG_CONFIG_FOUND)
+if(NOT TARGET Libxc::xc AND PKG_CONFIG_FOUND)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
   find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
 elseif(NOT PKG_CONFIG_FOUND)

From ab0ab5a51003a30e55649190b059d687a0272cdd Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Mon, 15 Jan 2024 15:54:22 +0800
Subject: [PATCH 08/15] fix for FindLibxc: changing imcompatible if statement

---
 cmake/FindLibxc.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 0d438a8583..f5494df3d8 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -31,7 +31,7 @@ find_package(Libxc HINTS
 if(NOT TARGET Libxc::xc AND PKG_CONFIG_FOUND)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
   find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
-elseif(NOT PKG_CONFIG_FOUND)
+elseif(NOT TARGET Libxc::xc NOT PKG_CONFIG_FOUND)
   message(FATAL_ERROR
           "LibXC : We need pkg-config to get all information about the libxc library")
 endif()

From f887d41057db9406196f4c93f9e440f4d4fa5919 Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Mon, 15 Jan 2024 15:56:00 +0800
Subject: [PATCH 09/15] fix for FindLibxc: changing imcompatible if statement

---
 cmake/FindLibxc.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index f5494df3d8..df9d5e5210 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -31,7 +31,7 @@ find_package(Libxc HINTS
 if(NOT TARGET Libxc::xc AND PKG_CONFIG_FOUND)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
   find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
-elseif(NOT TARGET Libxc::xc NOT PKG_CONFIG_FOUND)
+elseif(NOT TARGET Libxc::xc AND NOT PKG_CONFIG_FOUND)
   message(FATAL_ERROR
           "LibXC : We need pkg-config to get all information about the libxc library")
 endif()

From 7cdd7b4749cfeac5dc4f54dfa373be6315aee7b0 Mon Sep 17 00:00:00 2001
From: yizeyi18 <18586016708@163.com>
Date: Tue, 16 Jan 2024 15:17:09 +0800
Subject: [PATCH 10/15] update docs for installing pkg-config

---
 docs/quick_start/easy_install.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/quick_start/easy_install.md b/docs/quick_start/easy_install.md
index 4bb409495b..cb9c8e0cd4 100644
--- a/docs/quick_start/easy_install.md
+++ b/docs/quick_start/easy_install.md
@@ -28,7 +28,7 @@ These requirements support the calculation of plane-wave basis in ABACUS. For LC
 Some of these packages can be installed with popular package management system, such as `apt` and `yum`:
 
 ```bash
-sudo apt update && sudo apt install -y libopenblas-openmp-dev liblapack-dev libscalapack-mpi-dev libelpa-dev libfftw3-dev libcereal-dev libxc-dev g++ make cmake bc git
+sudo apt update && sudo apt install -y libopenblas-openmp-dev liblapack-dev libscalapack-mpi-dev libelpa-dev libfftw3-dev libcereal-dev libxc-dev g++ make cmake bc git pkgconf
 ```
 
 > Installing ELPA by apt only matches requirements on Ubuntu 22.04. For earlier linux distributions, you should build ELPA from source.

From 3ce7ac69de7ae8431410077a32d56e9be4684c75 Mon Sep 17 00:00:00 2001
From: Chun Cai <amoycaic@gmail.com>
Date: Wed, 17 Jan 2024 11:40:51 +0800
Subject: [PATCH 11/15] Update FindLibxc.cmake

---
 cmake/FindLibxc.cmake | 26 ++++----------------------
 1 file changed, 4 insertions(+), 22 deletions(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index df9d5e5210..630eb38ead 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -1,22 +1,5 @@
-###############################################################################
-# - Find ELPA
-# Find the native ELPA headers and libraries.
-#
-#  ELPA_FOUND        - True if libelpa is found.
-#  ELPA_LIBRARIES    - List of libraries when using libyaml
-#  ELPA_INCLUDE_DIR - Where to find ELPA headers.
-#
-
-#find_path(ELPA_INCLUDE_DIR
-#    elpa/elpa.h
-#    HINTS ${ELPA_DIR}
-#    PATH_SUFFIXES "include" "include/elpa"
-#    )
-
 include(FindPackageHandleStandardArgs)
 
-find_package(PkgConfig)
-
 if(DEFINED Libxc_DIR)
   string(APPEND CMAKE_PREFIX_PATH ";${Libxc_DIR}")
 endif()
@@ -28,14 +11,13 @@ find_package(Libxc HINTS
     ${Libxc_DIR}/lib/cmake/Libxc
     ${Libxc_DIR}/lib64/cmake/Libxc
   )
-if(NOT TARGET Libxc::xc AND PKG_CONFIG_FOUND)
+if(NOT TARGET Libxc::xc)
+  find_package(PkgConfig REQUIRED)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
-  find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
-elseif(NOT TARGET Libxc::xc AND NOT PKG_CONFIG_FOUND)
-  message(FATAL_ERROR
-          "LibXC : We need pkg-config to get all information about the libxc library")
 endif()
 
+find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
+
 # Copy the results to the output variables and target.
 # if find_package() above works, Libxc::xc would be present and
 # below would be skipped.

From e8438195b0ea38e0897c1bf6c0f4e46eb3f38bd1 Mon Sep 17 00:00:00 2001
From: Chun Cai <amoycaic@gmail.com>
Date: Wed, 17 Jan 2024 14:45:03 +0800
Subject: [PATCH 12/15] Update FindLibxc.cmake

---
 cmake/FindLibxc.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/FindLibxc.cmake b/cmake/FindLibxc.cmake
index 630eb38ead..4a3c04cba7 100644
--- a/cmake/FindLibxc.cmake
+++ b/cmake/FindLibxc.cmake
@@ -14,9 +14,9 @@ find_package(Libxc HINTS
 if(NOT TARGET Libxc::xc)
   find_package(PkgConfig REQUIRED)
   pkg_search_module(Libxc REQUIRED IMPORTED_TARGET GLOBAL libxc)
+  find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
 endif()
 
-find_package_handle_standard_args(Libxc DEFAULT_MSG Libxc_LINK_LIBRARIES Libxc_INCLUDE_DIRS)
 
 # Copy the results to the output variables and target.
 # if find_package() above works, Libxc::xc would be present and

From 821977decd280ef6a32c5936f7becc5524556e9d Mon Sep 17 00:00:00 2001
From: YI Zeping <18586016708@163.com>
Date: Wed, 17 Jan 2024 06:55:37 +0000
Subject: [PATCH 13/15] remove previous LibXC routine in CMakeLists.txt

Co-authored-by: Chun Cai <amoycaic@gmail.com>
---
 CMakeLists.txt | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 19bd7adeb4..d3db9f529d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -508,11 +508,7 @@ if(DEFINED Libxc_DIR)
   set(ENABLE_LIBXC ON)
 endif()
 if(ENABLE_LIBXC)
-#  find_package(Libxc REQUIRED HINTS
-#    ${Libxc_DIR}/share/cmake/Libxc
-#    ${Libxc_DIR}/lib/cmake/Libxc
-#    ${Libxc_DIR}/lib64/cmake/Libxc
-#  )
+  # use `cmake/FindLibxc.cmake` to detect Libxc installation with `pkg-config`
   find_package(Libxc REQUIRED)
   message(STATUS "Found Libxc: version " ${Libxc_VERSION})
   if(${Libxc_VERSION} VERSION_LESS 5.1.7)

From a9cbf70d83af005b7a5ccad10af94f32ca360de8 Mon Sep 17 00:00:00 2001
From: YI Zeping <18586016708@163.com>
Date: Wed, 17 Jan 2024 07:01:05 +0000
Subject: [PATCH 14/15] Update easy_install.md with Makefile-built LibXC
 supported

---
 docs/quick_start/easy_install.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/quick_start/easy_install.md b/docs/quick_start/easy_install.md
index cb9c8e0cd4..f38d56d229 100644
--- a/docs/quick_start/easy_install.md
+++ b/docs/quick_start/easy_install.md
@@ -116,7 +116,7 @@ Here, 'build' is the path for building ABACUS; and '-D' is used for setting up s
   - `FFTW3_DIR`: Path to FFTW3.
   - `CEREAL_INCLUDE_DIR`: Path to the parent folder of `cereal/cereal.hpp`. Will download from GitHub if absent.
   - `Libxc_DIR`: (Optional) Path to Libxc.
-  > Note: Building Libxc from source with Makefile does NOT support using it in CMake here. Please compile Libxc with CMake instead.
+  > Note: In ABACUS v3.5.1 or earlier, Libxc built from source with Makefile is NOT supported; please compile Libxc with CMake instead.
   - `LIBRI_DIR`: (Optional) Path to LibRI.
   - `LIBCOMM_DIR`: (Optional) Path to LibComm.
 

From 3eb0e2fe8d631706aba49a4f44600e5334b7abe7 Mon Sep 17 00:00:00 2001
From: YI Zeping <18586016708@163.com>
Date: Wed, 17 Jan 2024 07:15:18 +0000
Subject: [PATCH 15/15] Update easy_install.md to include different behavior in
 different version on finding ELPA

---
 docs/quick_start/easy_install.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/quick_start/easy_install.md b/docs/quick_start/easy_install.md
index f38d56d229..45adc8e60a 100644
--- a/docs/quick_start/easy_install.md
+++ b/docs/quick_start/easy_install.md
@@ -111,7 +111,7 @@ Here, 'build' is the path for building ABACUS; and '-D' is used for setting up s
   - `LAPACK_DIR`: Path to OpenBLAS library `libopenblas.so`(including BLAS and LAPACK)
   - `SCALAPACK_DIR`: Path to ScaLAPACK library `libscalapack.so`
   - `ELPA_DIR`: Path to ELPA install directory; should be the folder containing 'include' and 'lib'.
-  > Note: If you install ELPA from source and have no `pkg-config` installed, please add a symlink to avoid the additional include file folder with version name: `ln -s elpa/include/elpa-2021.05.002/elpa elpa/include/elpa` to help the build system find ELPA headers.
+  > Note: In ABACUS v3.5.1 or earlier, if you install ELPA from source , please add a symlink to avoid the additional include file folder with version name: `ln -s elpa/include/elpa-2021.05.002/elpa elpa/include/elpa` to help the build system find ELPA headers.
 
   - `FFTW3_DIR`: Path to FFTW3.
   - `CEREAL_INCLUDE_DIR`: Path to the parent folder of `cereal/cereal.hpp`. Will download from GitHub if absent.