Add optional DFT-D4 support

Author: Growl1234

CMakeLists.txt

@@ -34,6 +34,7 @@ option(USE_ELPA "Enable ELPA for LCAO" ON)
 option(ENABLE_LIBRI "Enable LibRI for hybrid functional" OFF)
 option(ENABLE_LIBCOMM "Enable LibComm" OFF)
 option(ENABLE_PEXSI "Enable PEXSI for LCAO" OFF)
+option(ENABLE_DFTD4 "Enable DFT-D4 dispersion correction" OFF)
 
 option(BUILD_TESTING "Build unittests" OFF)
 option(DEBUG_INFO "Print message to debug" OFF)
@@ -236,6 +237,18 @@ if(ENABLE_COVERAGE)
   add_coverage(${ABACUS_BIN_NAME})
 endif()
 
+if(ENABLE_DFTD4)
+  # DFTD4 requires enabling C and Fortran to work
+  enable_language(C)
+  enable_language(Fortran)
+  # Avoid custom-lapack fallback when resolving DFT-D4 dependencies
+  find_package(BLAS REQUIRED)
+  find_package(LAPACK REQUIRED)
+  find_package(dftd4 4.2.0 REQUIRED)
+  if(NOT TARGET dftd4::dftd4)
+    message(FATAL_ERROR "DFT-D4 was found, but target dftd4::dftd4 is missing.")
+  endif()
+endif()
 
 macro(set_if_higher VARIABLE VALUE)
   if(${VARIABLE} LESS ${VALUE})

source/source_estate/elecstate_print.cpp

@@ -249,6 +249,11 @@ void print_etot(const Magnetism& magnet,
             titles.push_back("E_vdwD3");
             energies_Ry.push_back(elec.f_en.evdw);
         }
+        else if (vdw_method == "d4")
+        {
+            titles.push_back("E_vdwD4");
+            energies_Ry.push_back(elec.f_en.evdw);
+        }
 
         // mohan add 20251108
 		if (PARAM.inp.dft_plus_u)

source/source_hamilt/module_vdw/CMakeLists.txt

@@ -1,16 +1,25 @@
-add_library(
-        vdw
-        OBJECT
-        vdwd2_parameters.cpp
-        vdwd3_parameters_tab.cpp
-        vdwd3_parameters.cpp
-        vdwd2.cpp
-        vdwd3.cpp
-        vdwd3_autoset_xcname.cpp
-        vdwd3_autoset_xcparam.cpp
-        vdw.cpp
+set(vdw_sources
+    vdwd2_parameters.cpp
+    vdwd3_parameters_tab.cpp
+    vdwd3_parameters.cpp
+    vdwd2.cpp
+    vdwd3.cpp
+    vdwd3_autoset_xcname.cpp
+    vdwd3_autoset_xcparam.cpp
+    vdw.cpp
 )
 
+if(ENABLE_DFTD4)
+  list(APPEND vdw_sources vdwd4.cpp)
+endif()
+
+add_library(vdw OBJECT ${vdw_sources})
+
+if(ENABLE_DFTD4)
+  target_link_libraries(vdw PUBLIC dftd4::dftd4)
+  target_compile_definitions(vdw PUBLIC __DFTD4)
+endif()
+
 if(ENABLE_COVERAGE)
   add_coverage(vdw)
 endif()
@@ -19,4 +28,4 @@ if(BUILD_TESTING)
   if(ENABLE_MPI)
     add_subdirectory(test)
   endif()
-endif()
+endif()

source/source_hamilt/module_vdw/vdw.cpp

@@ -6,6 +6,10 @@
 #include "vdwd3.h"
 #include "source_base/tool_quit.h"
 
+#ifdef __DFTD4
+#include "vdwd4.h"
+#endif
+
 std::string parse_xcname(const std::string &xc_input,
                          const std::vector<std::string> &xc_psp)
 {
@@ -70,6 +74,28 @@ std::unique_ptr<Vdw> make_vdw(const UnitCell &ucell,
         vdw_ptr->parameter().initial_parameters(parse_xcname(input.dft_functional, xc_psp), input, plog);
         return vdw_ptr;
     }
+    else if (input.vdw_method == "d4")
+    {
+#ifdef __DFTD4
+        std::vector<std::string> xc_psp(ucell.ntype);
+        for (int it = 0; it < ucell.ntype; it++)
+        {
+            xc_psp[it] = ucell.atoms[it].ncpp.xc_func;
+        }
+
+        std::string xc_name = input.vdw_d4_xc;
+        if (xc_name == "default")
+        {
+            xc_name = parse_xcname(input.dft_functional, xc_psp);
+        }
+
+        return vdw::make_unique<Vdwd4>(ucell, xc_name, input);
+#else
+        ModuleBase::WARNING_QUIT("ModuleHamiltGeneral::ModuleVDW::make_vdw",
+                                 "DFT-D4 support was not enabled at build time. "
+                                 "Rebuild ABACUS with -DENABLE_DFTD4=ON.");
+#endif
+    }
     else if (input.vdw_method != "none")
     {
         ModuleBase::WARNING_QUIT("ModuleHamiltGeneral::ModuleVDW::make_vdw",