Merge pull request sxs-collaboration#5343 from nilsvu/find_fftw

Find FFTW3 with CMake

cmake/FindFFTW.cmake

@@ -0,0 +1,36 @@
+# Distributed under the MIT License.
+# See LICENSE.txt for details.
+
+# Find FFTW3 (The Fastest Fourier Transform in the West)
+# http://www.fftw.org/
+#
+# Defines the `FFTW::FFTW` target to link against.
+
+if(NOT FFTW_ROOT)
+  # Need to set to empty to avoid warnings with --warn-uninitialized
+  set(FFTW_ROOT "")
+  set(FFTW_ROOT $ENV{FFTW_ROOT})
+endif()
+
+find_path(FFTW_INCLUDE_DIR
+  NAMES fftw3.h
+  PATH_SUFFIXES include
+  HINTS ${FFTW_ROOT}
+  )
+
+find_library(FFTW_LIB
+  NAMES fftw3
+  PATH_SUFFIXES lib64 lib
+  HINTS ${FFTW_ROOT}
+  )
+
+if (FFTW_INCLUDE_DIR AND FFTW_LIB)
+  add_library(FFTW::FFTW INTERFACE IMPORTED)
+  target_include_directories(FFTW::FFTW INTERFACE ${FFTW_INCLUDE_DIR})
+  target_link_libraries(FFTW::FFTW INTERFACE ${FFTW_LIB})
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(FFTW
+  REQUIRED_VARS FFTW_INCLUDE_DIR FFTW_LIB)
+mark_as_advanced(FFTW_INCLUDE_DIR FFTW_LIB)

cmake/FindSpEC.cmake

@@ -45,14 +45,29 @@ find_package(MPI COMPONENTS C)
 
 if (SPEC_PACKAGED_EXPORTER_LIB AND SPEC_EXPORTER_FACTORY_OBJECTS AND
     SPEC_EXPORTER_INCLUDE_DIR AND MPI_C_FOUND)
+  add_library(SpEC::Exporter INTERFACE IMPORTED)
+  target_include_directories(
+    SpEC::Exporter INTERFACE ${SPEC_EXPORTER_INCLUDE_DIR})
+  add_interface_lib_headers(
+    TARGET SpEC::Exporter
+    HEADERS
+    Exporter.hpp
+  )
+  target_link_libraries(
+    SpEC::Exporter
+    INTERFACE
+    MPI::MPI_C
+    # The order of these next two lines is important
+    ${SPEC_EXPORTER_FACTORY_OBJECTS}
+    ${SPEC_PACKAGED_EXPORTER_LIB}
+  )
 
   # Deal with FFTW3
   #
   # If it was dynamically linked into SpEC then we need to dynamically link it
   # into SpECTRE.
   set(_MACHINE_DEF_FILE
     ${SPEC_ROOT}/MakefileRules/this_machine.def)
-  set(_FFTW3_LINK_FLAGS "")
   if (EXISTS ${_MACHINE_DEF_FILE})
     file(STRINGS ${_MACHINE_DEF_FILE} _MACHINE_DEF)
     # Filter starting comments
@@ -61,34 +76,13 @@ if (SPEC_PACKAGED_EXPORTER_LIB AND SPEC_EXPORTER_FACTORY_OBJECTS AND
     list(TRANSFORM _MACHINE_DEF REPLACE "[ ]*#.*" "")
     string(REGEX MATCH "FFTW_LIB[^;]+"
       _FFTW3_DEF "${_MACHINE_DEF}")
-    string(REGEX REPLACE
-      "FFTW_LIB[ +]+=[ ]" ""
-      _FFTW3_LINK_FLAGS
-      ${_FFTW3_DEF})
     string(FIND ${_FFTW3_DEF} "-lfftw3" _FOUND_FFTW3_SHARED)
-    # If we did not find a shared lib, do not add linking flags.
-    if(${_FOUND_FFTW3_SHARED} STREQUAL -1)
-      set(_FFTW3_LINK_FLAGS "")
+    # If we found a shared FFTW lib in SpEC, find and link FFTW here
+    if(NOT ${_FOUND_FFTW3_SHARED} STREQUAL "-1")
+      find_package(FFTW REQUIRED)
+      target_link_libraries(SpEC::Exporter INTERFACE FFTW::FFTW)
     endif()
   endif()
-
-  add_library(SpEC::Exporter INTERFACE IMPORTED)
-  target_include_directories(
-    SpEC::Exporter INTERFACE ${SPEC_EXPORTER_INCLUDE_DIR})
-  add_interface_lib_headers(
-    TARGET SpEC::Exporter
-    HEADERS
-    Exporter.hpp
-  )
-  target_link_libraries(
-    SpEC::Exporter
-    INTERFACE
-    MPI::MPI_C
-    # The order of these next two lines is important
-    ${SPEC_EXPORTER_FACTORY_OBJECTS}
-    ${SPEC_PACKAGED_EXPORTER_LIB}
-    ${_FFTW3_LINK_FLAGS}
-  )
 endif()
 
 include(FindPackageHandleStandardArgs)