update variable names

cmake/CMakeLists.txt

@@ -971,6 +971,20 @@ if(PKG_KOKKOS)
   endif()
 endif()
 if(PKG_KSPACE)
+  if (LMP_HEFFTE)
+    message(STATUS "<<< FFT settings >>>
+-- Primary FFT lib:  heFFTe")
+    if (HEFFTE_BACKEND)
+      message(STATUS "heFFTe backend:  ${HEFFTE_BACKEND}")
+    else()
+      message(STATUS "heFFTe backend:  stock (not intended for production)")
+    endif()
+    if(FFT_SINGLE)
+      message(STATUS "Using single precision FFTs")
+    else()
+      message(STATUS "Using double precision FFTs")
+    endif()
+  else()
     message(STATUS "<<< FFT settings >>>
 -- Primary FFT lib:  ${FFT}")
     if(FFT_SINGLE)
@@ -1005,6 +1019,7 @@ if(PKG_KSPACE)
         message(STATUS "Kokkos FFT: ${FFT}")
       endif()
     endif()
+  endif()
 endif()
 if(BUILD_DOC)
   message(STATUS "<<< Building HTML Manual >>>")

cmake/Modules/Packages/KSPACE.cmake

@@ -46,17 +46,21 @@ else()
   target_compile_definitions(lammps PRIVATE -DFFT_KISS)
 endif()
 
-option(FFT_HEFFTE  "Use heFFTe as the distributed FFT engine."  OFF)
+option(LMP_HEFFTE  "Use heFFTe as the distributed FFT engine, supersedes the FFT option."  OFF)
-if(FFT_HEFFTE)
+if(LMP_HEFFTE)
   # if FFT_HEFFTE is enabled, switch the builtin FFT engine with Heffte
-  if(FFT STREQUAL "FFTW3") # respect the backend choice, FFTW or MKL
+  set(HEFFTE_BACKEND_VALUES FFTW MKL)
+  set(HEFFTE_BACKEND "" CACHE STRING "Select heFFTe backend, e.g., FFTW or MKL")
+  set_property(CACHE HEFFTE_BACKEND PROPERTY STRINGS ${HEFFTE_BACKEND_VALUES})
+
+  if(HEFFTE_BACKEND STREQUAL "FFTW") # respect the backend choice, FFTW or MKL
     set(HEFFTE_COMPONENTS "FFTW")
     set(Heffte_ENABLE_FFTW "ON" CACHE BOOL "Enables FFTW backend for heFFTe")
-  elseif(FFT STREQUAL "MKL")
+  elseif(HEFFTE_BACKEND STREQUAL "MKL")
     set(HEFFTE_COMPONENTS "MKL")
     set(Heffte_ENABLE_MKL "ON" CACHE BOOL "Enables MKL backend for heFFTe")
   else()
-    message(FATAL_ERROR "Using -DFFT_HEFFTE=ON, requires FFT either FFTW or MKL")
+    message(WARNING "HEFFTE_BACKEND not selected, defaulting to 'stock' backend, which is not intended for production")
   endif()
 
   find_package(Heffte 2.3.0 QUIET COMPONENTS ${HEFFTE_COMPONENTS})
@@ -72,7 +76,7 @@ if(FFT_HEFFTE)
     set_target_properties(lammps PROPERTIES INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
   endif()
 
-  target_compile_definitions(lammps PRIVATE -DHEFFTE)
+  target_compile_definitions(lammps PRIVATE -DLMP_HEFFTE "-DHEFFTE_${HEFFTE_BACKEND}")
   target_link_libraries(lammps PRIVATE Heffte::Heffte)
 endif()
 

src/KSPACE/fft3d_wrap.cpp

@@ -27,7 +27,7 @@ FFT3d::FFT3d(LAMMPS *lmp, MPI_Comm comm, int nfast, int nmid, int nslow,
              int out_klo, int out_khi,
              int scaled, int permute, int *nbuf, int usecollective) : Pointers(lmp)
 {
-  #ifndef HEFFTE
+  #ifndef LMP_HEFFTE
   plan = fft_3d_create_plan(comm,nfast,nmid,nslow,
                             in_ilo,in_ihi,in_jlo,in_jhi,in_klo,in_khi,
                             out_ilo,out_ihi,out_jlo,out_jhi,out_klo,out_khi,
@@ -56,7 +56,7 @@ FFT3d::FFT3d(LAMMPS *lmp, MPI_Comm comm, int nfast, int nmid, int nslow,
 
 FFT3d::~FFT3d()
 {
-  #ifndef HEFFTE
+  #ifndef LMP_HEFFTE
   fft_3d_destroy_plan(plan);
   #endif
 }
@@ -65,7 +65,7 @@ FFT3d::~FFT3d()
 
 void FFT3d::compute(FFT_SCALAR *in, FFT_SCALAR *out, int flag)
 {
-  #ifndef HEFFTE
+  #ifndef LMP_HEFFTE
   fft_3d((FFT_DATA *) in,(FFT_DATA *) out,flag,plan);
   #else
   if (flag == 1)
@@ -86,7 +86,7 @@ void FFT3d::compute(FFT_SCALAR *in, FFT_SCALAR *out, int flag)
 
 void FFT3d::timing1d(FFT_SCALAR *in, int nsize, int flag)
 {
-  #ifndef HEFFTE
+  #ifndef LMP_HEFFTE
   fft_1d_only((FFT_DATA *) in,nsize,flag,plan);
   #endif
 }

src/KSPACE/fft3d_wrap.h

@@ -17,16 +17,18 @@
 #include "fft3d.h"    // IWYU pragma: export
 #include "pointers.h"
 
-#ifdef HEFFTE
+#ifdef LMP_HEFFTE
 #include "heffte.h"
 // select the backend
-#if defined(FFT_FFTW3)
+#if defined(HEFFTE_FFTW)
 using heffte_backend = heffte::backend::fftw;
-#elif defined(FFT_MKL)
+#elif defined(HEFFTE_MKL)
 using heffte_backend = heffte::backend::mkl;
+#elif defined(HEFFTE_)
+using heffte_backend = heffte::backend::stock;
 #endif
 
-#endif // HEFFTE
+#endif // LMP_HEFFTE
 
 namespace LAMMPS_NS {
 
@@ -41,7 +43,7 @@ class FFT3d : protected Pointers {
   void timing1d(FFT_SCALAR *, int, int);
 
  private:
-  #ifdef HEFFTE
+  #ifdef LMP_HEFFTE
   // the heFFTe plan supersedes the internal fft_plan_3d
   std::unique_ptr<heffte::fft3d<heffte_backend>> heffte_plan;
   std::vector<std::complex<FFT_SCALAR>> heffte_workspace;