CMakeLists.txt

# Copyright (c) 2010-2022, Lawrence Livermore National Security, LLC. Produced
# at the Lawrence Livermore National Laboratory. All Rights reserved. See files
# LICENSE and NOTICE for details. LLNL-CODE-806117.
#
# This file is part of the MFEM library. For more information and source code
# availability visit https://mfem.org.
#
# MFEM is free software; you can redistribute it and/or modify it under the
# terms of the BSD-3 license. We welcome feedback and contributions, see file
# CONTRIBUTING.md for details.

# The variable CMAKE_CXX_STANDARD and related were introduced in CMake v3.1
cmake_minimum_required(VERSION 3.1)
set(USER_CONFIG "${CMAKE_CURRENT_SOURCE_DIR}/config/user.cmake" CACHE PATH
  "Path to optional user configuration file.")

# Require C++11 and disable compiler-specific extensions
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

# Load user settings before the defaults - this way the defaults will not
# overwrite the user set options. If the user has not set all options, we still
# have the defaults.
message(STATUS "(optional) USER_CONFIG = ${USER_CONFIG}")
include("${USER_CONFIG}" OPTIONAL)
include("${CMAKE_CURRENT_SOURCE_DIR}/config/defaults.cmake")

# Allow overwriting of the compiler by setting CXX/MPICXX on the command line or
# in user.cmake.
if (NOT CMAKE_CXX_COMPILER)
  if (CXX)
    set(CMAKE_CXX_COMPILER ${CXX})
    # Avoid some issues when CXX is defined
    unset(CXX)
    unset(CXX CACHE)
  endif()
  if (MFEM_USE_MPI AND MPICXX)
    # In parallel MPICXX takes precedence, if defined.
    set(CMAKE_CXX_COMPILER ${MPICXX})
    # Setting the variables below circumvents autodetection, see FindMPI.cmake.
    set(MPI_CXX_INCLUDE_PATH "")
    set(MPI_CXX_LIBRARIES "")
  endif()
endif()

#-------------------------------------------------------------------------------
# Project name and version
#-------------------------------------------------------------------------------
project(mfem NONE)
# Current version of MFEM, see also `makefile`.
#   mfem_VERSION = (string)
#   MFEM_VERSION = (int)   [automatically derived from mfem_VERSION]
set(${PROJECT_NAME}_VERSION 4.4.1)

# Prohibit in-source build
if (${PROJECT_SOURCE_DIR} STREQUAL ${PROJECT_BINARY_DIR})
  message(FATAL_ERROR
    "MFEM does not support in-source CMake builds at this time.")
endif (${PROJECT_SOURCE_DIR} STREQUAL ${PROJECT_BINARY_DIR})

# Set xSDK defaults.
set(USE_XSDK_DEFAULTS_DEFAULT OFF)
set(XSDK_ENABLE_CXX ON)
set(XSDK_ENABLE_C OFF)
set(XSDK_ENABLE_Fortran OFF)

# Check if we need to enable C or Fortran.
if (CMAKE_VERSION VERSION_LESS 3.2 OR
    MFEM_USE_CONDUIT OR
    MFEM_USE_SIDRE OR
    MFEM_USE_PETSC)
   # This seems to be needed by:
   #  * find_package(BLAS REQUIRED) and
   #  * find_package(HDF5 REQUIRED) needed, in turn, by:
   #    - find_package(AXOM REQUIRED)
   #  * find_package(PETSc REQUIRED)
   set(XSDK_ENABLE_C ON)
endif()
if (MFEM_USE_STRUMPACK)
  # Just needed to find the MPI_Fortran libraries to link with
  set(XSDK_ENABLE_Fortran ON)
endif()
if (MFEM_USE_GINKGO AND ("${CMAKE_CXX_STANDARD}" LESS "14"))
  set(CMAKE_CXX_STANDARD 14)
endif()

# Include xSDK default CMake file.
include("${CMAKE_CURRENT_SOURCE_DIR}/config/XSDKDefaults.cmake")

# Enable languages.
enable_language(CXX)
if (MINGW)
   # MinGW GCC does not expose the functions jn/_jn, yn/_yn (used in Example
   # 25/25p) unless we use '-std=gnu++11':
   set(CMAKE_CXX_EXTENSIONS ON)
endif()
if (MFEM_USE_CUDA)
   if (MFEM_USE_HIP)
      message(FATAL_ERROR " *** MFEM_USE_HIP cannot be combined with MFEM_USE_CUDA.")
   endif()
   # MFEM_USE_CUDA requires CMake 3.8 or newer (for direct CUDA support)
   cmake_minimum_required(VERSION 3.8 FATAL_ERROR)
   # Use ${CMAKE_CXX_COMPILER} as the cuda host compiler.
   if (NOT CMAKE_CUDA_HOST_COMPILER)
      set(CMAKE_CUDA_HOST_COMPILER ${CMAKE_CXX_COMPILER})
   endif()
   enable_language(CUDA)
   set(CMAKE_CUDA_STANDARD 11)
   if (MFEM_USE_GINKGO)
     set(CMAKE_CUDA_STANDARD 14)
   endif()
   set(CMAKE_CUDA_STANDARD_REQUIRED ON)
   set(CMAKE_CUDA_EXTENSIONS OFF)
   set(CUDA_FLAGS "--expt-extended-lambda")
   if (CMAKE_VERSION VERSION_LESS 3.18.0)
      set(CUDA_FLAGS "-arch=${CUDA_ARCH} ${CUDA_FLAGS}")
   elseif (NOT CMAKE_CUDA_ARCHITECTURES)
      string(REGEX REPLACE "^sm_" "" ARCH_NUMBER "${CUDA_ARCH}")
      if ("${CUDA_ARCH}" STREQUAL "sm_${ARCH_NUMBER}")
         set(CMAKE_CUDA_ARCHITECTURES "${ARCH_NUMBER}")
      else()
         message(FATAL_ERROR "Unknown CUDA_ARCH: ${CUDA_ARCH}")
      endif()
   else()
      set(CUDA_ARCH "CMAKE_CUDA_ARCHITECTURES: ${CMAKE_CUDA_ARCHITECTURES}")
   endif()
   message(STATUS "Using CUDA architecture: ${CUDA_ARCH}")
   if (CMAKE_VERSION VERSION_LESS 3.12.0)
      # CMake versions 3.8 and 3.9 require this to work; 3.10 and 3.11 are not
      # tested and may not actually need this (but should be ok to keep).
      set(CUDA_FLAGS "-ccbin=${CMAKE_CXX_COMPILER} ${CUDA_FLAGS}")
      set(CMAKE_CUDA_HOST_LINK_LAUNCHER ${CMAKE_CXX_COMPILER})
   endif()
   set(CMAKE_CUDA_FLAGS "${CUDA_FLAGS}" CACHE STRING
       "CUDA flags set for MFEM" FORCE)
   set(CUSPARSE_FOUND TRUE)
   set(CUSPARSE_LIBRARIES "cusparse")
   set(CUBLAS_FOUND TRUE)
   set(CUSBLAS_LIBRARIES "cublas")
endif()

if (XSDK_ENABLE_C)
   enable_language(C)
endif()
if (XSDK_ENABLE_Fortran)
   enable_language(Fortran)
endif()

# Suppress warnings about MACOSX_RPATH
set(CMAKE_MACOSX_RPATH OFF CACHE BOOL "")

# CMake needs to know where to find things
set(MFEM_CMAKE_PATH ${PROJECT_SOURCE_DIR}/config)
set(CMAKE_MODULE_PATH ${MFEM_CMAKE_PATH}/cmake/modules)

# Load MFEM CMake utilities.
include(MfemCmakeUtilities)

string(TOUPPER "${PROJECT_NAME}" PROJECT_NAME_UC)
mfem_version_to_int(${${PROJECT_NAME}_VERSION} ${PROJECT_NAME_UC}_VERSION)
set(${PROJECT_NAME_UC}_VERSION_STRING ${${PROJECT_NAME}_VERSION})
if (EXISTS ${PROJECT_SOURCE_DIR}/.git)
   execute_process(
     COMMAND git describe --all --long --abbrev=40 --dirty --always
     WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
     OUTPUT_VARIABLE ${PROJECT_NAME_UC}_GIT_STRING
     ERROR_QUIET OUTPUT_STRIP_TRAILING_WHITESPACE)
endif()
if (NOT ${PROJECT_NAME_UC}_GIT_STRING)
   set(${PROJECT_NAME_UC}_GIT_STRING "(unknown)")
endif()

#-------------------------------------------------------------------------------
# Process configuration options
#-------------------------------------------------------------------------------

# MFEM_DEBUG
if (CMAKE_BUILD_TYPE MATCHES "Debug|debug|DEBUG")
  set(MFEM_DEBUG ON)
else()
  set(MFEM_DEBUG OFF)
endif()

# AMD HIP
if (MFEM_USE_HIP)
  if (HIP_ARCH)
    message(STATUS "Using HIP architecture: ${HIP_ARCH}")
    set(GPU_TARGETS "${HIP_ARCH}" CACHE STRING "HIP targets to compile for")
  endif()
  if (ROCM_PATH)
    list(INSERT CMAKE_PREFIX_PATH 0 ${ROCM_PATH})
  endif()
  find_package(HIP REQUIRED)
  find_package(HIPSPARSE REQUIRED)
endif()

# MPI -> hypre; PETSc (optional)
if (MFEM_USE_MPI)
  find_package(MPI REQUIRED)
  set(MPI_CXX_INCLUDE_DIRS ${MPI_CXX_INCLUDE_PATH})
  if (MFEM_MPIEXEC)
    set(MPIEXEC ${MFEM_MPIEXEC})
  endif()
  if (MFEM_MPIEXEC_NP)
    set(MPIEXEC_NUMPROC_FLAG ${MFEM_MPIEXEC_NP})
  endif()
  # Parallel MFEM depends on hypre
  find_package(HYPRE REQUIRED)
  set(MFEM_HYPRE_VERSION ${HYPRE_VERSION})
  if (MFEM_USE_PETSC)
    find_package(PETSc REQUIRED)
    message(STATUS "Found PETSc version ${PETSC_VERSION}")
    if (PETSC_VERSION AND (PETSC_VERSION VERSION_LESS 3.8.0))
      message(FATAL_ERROR "PETSc version >= 3.8.0 is required")
    endif()
    set(PETSC_INCLUDE_DIRS ${PETSC_INCLUDES})
    if (MFEM_USE_SLEPC)
      find_package(SLEPc REQUIRED config)
      message(STATUS "Found SLEPc version ${SLEPC_VERSION}")
    endif()
  endif()
else()
  set(PKGS_NEED_MPI SUPERLU MUMPS PETSC SLEPC STRUMPACK PUMI)
  foreach(PKG IN LISTS PKGS_NEED_MPI)
    if (MFEM_USE_${PKG})
      message(STATUS "Disabling package ${PKG} - requires MPI")
      set(MFEM_USE_${PKG} OFF CACHE BOOL "Disabled - requires MPI" FORCE)
    endif()
  endforeach()
endif()

if (MFEM_USE_METIS)
  find_package(METIS REQUIRED)
endif()

if (MFEM_USE_GINKGO)
  find_package(Ginkgo REQUIRED)
  if (Ginkgo_FOUND)
    get_target_property(Ginkgo_INCLUDE_DIRS
      Ginkgo::ginkgo INTERFACE_INCLUDE_DIRECTORIES)
    set(Ginkgo_LIBRARIES Ginkgo::ginkgo)
  endif()
endif()

# zlib
if (MFEM_USE_ZLIB)
  find_package(ZLIB REQUIRED)
endif()

# Backtrace with libunwind
if (MFEM_USE_LIBUNWIND)
  set(MFEMBacktrace_REQUIRED_PACKAGES "Libunwind" "LIBDL" "CXXABIDemangle")
  find_package(MFEMBacktrace REQUIRED)
endif()

# BLAS, LAPACK
if (MFEM_USE_LAPACK)
  find_package(BLAS REQUIRED)
  find_package(LAPACK REQUIRED)
endif()

# OpenMP
if (MFEM_USE_OPENMP OR MFEM_USE_LEGACY_OPENMP)
  if (NOT MFEM_THREAD_SAFE AND MFEM_USE_LEGACY_OPENMP)
    message(FATAL_ERROR " *** MFEM_USE_LEGACY_OPENMP requires MFEM_THREAD_SAFE=ON.")
  endif()
  find_package(OpenMP REQUIRED)
  set(OPENMP_LIBRARIES ${OpenMP_CXX_LIBRARIES})
  if(APPLE)
    # On macOS, the compiler needs additional help to find the <omp.h> header.
    # See issue #2642 for more information.
    set(OPENMP_INCLUDE_DIRS ${OpenMP_CXX_INCLUDE_DIRS})
  endif(APPLE)
endif()

# SuiteSparse (before SUNDIALS which may depend on KLU)
if (MFEM_USE_SUITESPARSE)
  find_package(SuiteSparse REQUIRED
    UMFPACK KLU AMD BTF CHOLMOD COLAMD CAMD CCOLAMD config)
endif()

# SUNDIALS
if (MFEM_USE_SUNDIALS)
  set(SUNDIALS_COMPONENTS CVODES ARKODE KINSOL NVector_Serial)
  if (MFEM_USE_MPI)
    list(APPEND SUNDIALS_COMPONENTS NVector_Parallel NVector_MPIPlusX)
  endif()
  if (MFEM_USE_CUDA)
    list(APPEND SUNDIALS_COMPONENTS NVector_Cuda)
  endif()
  find_package(SUNDIALS REQUIRED ${SUNDIALS_COMPONENTS})
endif()

# Mesquite
if (MFEM_USE_MESQUITE)
  find_package(Mesquite REQUIRED)
endif()

# SuperLU_DIST can only be enabled in parallel
if (MFEM_USE_SUPERLU)
  if (MFEM_USE_MPI)
    find_package(SuperLUDist REQUIRED)
  else()
    message(FATAL_ERROR " *** SuperLU_DIST requires that MPI be enabled.")
  endif()
endif()

# MUMPS can only be enabled in parallel
if (MFEM_USE_MUMPS)
  if (MFEM_USE_MPI)
    find_package(MUMPS REQUIRED mumps_common pord)
  else()
    message(FATAL_ERROR " *** MUMPS requires that MPI be enabled.")
  endif()
endif()

# STRUMPACK can only be enabled in parallel
if (MFEM_USE_STRUMPACK)
  if (MFEM_USE_MPI)
    find_package(STRUMPACK REQUIRED)
  else()
    message(FATAL_ERROR " *** STRUMPACK requires that MPI be enabled.")
  endif()
endif()

# GnuTLS
if (MFEM_USE_GNUTLS)
  find_package(_GnuTLS REQUIRED)
endif()

# GSLIB
if (MFEM_USE_GSLIB)
  find_package(GSLIB REQUIRED)
endif()

# NetCDF
if (MFEM_USE_NETCDF)
  find_package(NetCDF REQUIRED)
endif()

# MPFR
if (MFEM_USE_MPFR)
  find_package(MPFR REQUIRED)
endif()

if (MFEM_USE_CEED)
  find_package(libCEED REQUIRED)
endif()

if (MFEM_USE_AMGX)
  find_package(AMGX REQUIRED)
endif()

if (MFEM_USE_CONDUIT)
    find_package(Conduit REQUIRED conduit relay blueprint)
endif()

if (MFEM_USE_FMS)
    find_package(FMS REQUIRED fms)
endif()

# Axom/Sidre
if (MFEM_USE_SIDRE)
  find_package(Axom REQUIRED Axom)
endif()

# PUMI
if (MFEM_USE_PUMI)
  # If PUMI_DIR was specified, only link to that directory,
  # i.e. don't link to another installation in /usr/lib by mistake
  find_package(SCOREC 2.2.6 REQUIRED OPTIONAL_COMPONENTS gmi_sim
    CONFIG PATHS ${PUMI_DIR} NO_DEFAULT_PATH)
  if (SCOREC_FOUND)
    # Define a header file with the MFEM_USE_SIMMETRIX preprocessor variable
    set(MFEM_USE_SIMMETRIX ${SCOREC_gmi_sim_FOUND})
    set(PUMI_FOUND ${SCOREC_FOUND})
    get_target_property(PUMI_INCLUDE_DIRS
      SCOREC::apf INTERFACE_INCLUDE_DIRECTORIES)
    set(PUMI_LIBRARIES SCOREC::core)
  endif()
endif()

# Moonolith
if(MFEM_USE_MOONOLITH)
  find_package(ParMoonolith REQUIRED)
  if(ParMoonolith_FOUND)
    get_target_property(
      MOONOLITH_INCLUDE_DIRS ParMoonolith::par_moonolith
      INTERFACE_INCLUDE_DIRECTORIES)
    set(MOONOLITH_FOUND TRUE)
    set(MOONOLITH_LIBRARIES ParMoonolith::par_moonolith)
    message(
      STATUS
      "MOONOLITH_LIBRARIES=${MOONOLITH_LIBRARIES}, MOONOLITH_INCLUDE_DIRS=${MOONOLITH_INCLUDE_DIRS}")
  endif()
endif()

# HiOp optimizer
if (MFEM_USE_HIOP)
  find_package(HIOP REQUIRED)
  # find_package updates HIOP_FOUND, HIOP_INCLUDE_DIRS, HIOP_LIBRARIES
endif()

# CoDiPack package
if (MFEM_USE_CODIPACK)
  find_package(CODIPACK REQUIRED)
  # find_package updates CODIPACK_FOUND, CODIPACK_INCLUDE_DIRS, CODIPACK_LIBRARIES
endif()

# OCCA
if (MFEM_USE_OCCA)
   find_package(OCCA REQUIRED)
endif()

# RAJA
if (MFEM_USE_RAJA)
   find_package(RAJA REQUIRED)
endif()

# UMPIRE
if (MFEM_USE_UMPIRE)
   find_package(UMPIRE REQUIRED)
endif()

# GOOGLE-BENCHMARK
if (MFEM_USE_BENCHMARK)
   find_package(Benchmark REQUIRED)
endif()

# Caliper
if (MFEM_USE_CALIPER)
  find_package(Caliper REQUIRED)
endif()

# Algoim
if (MFEM_USE_ALGOIM)
  find_package(Algoim REQUIRED)
endif()

# ADIOS2 for parallel I/O
if (MFEM_USE_ADIOS2)
   find_package(ADIOS2 REQUIRED)
endif()

if (MFEM_USE_MKL_CPARDISO)
  if (MFEM_USE_MPI)
   find_package(MKL_CPARDISO REQUIRED MKL_SEQUENTIAL MKL_LP64 MKL_MPI_WRAPPER)
  endif()
endif()

# PARELAG
if (MFEM_USE_PARELAG)
   find_package(PARELAG REQUIRED)
endif()

# Enzyme
if (MFEM_USE_ENZYME)
   find_package(ENZYME REQUIRED)
endif()

# MFEM_TIMER_TYPE
if (NOT DEFINED MFEM_TIMER_TYPE)
  if (APPLE)
    # use std::clock from <ctime> for UserTime and
    # use mach_absolute_time from <mach/mach_time.h> for RealTime
    set(MFEM_TIMER_TYPE 4)
  elseif (WIN32)
    set(MFEM_TIMER_TYPE 3) # QueryPerformanceCounter from <windows.h>
  else()
    find_package(POSIXClocks)
    if (POSIXCLOCKS_FOUND)
      set(MFEM_TIMER_TYPE 2) # use high-resolution POSIX clocks
    else()
      set(MFEM_TIMER_TYPE 0) # use std::clock from <ctime>
    endif()
  endif()
endif()

# List all possible libraries in order of dependencies.
# [METIS < SuiteSparse]:
#    With newer versions of SuiteSparse which include METIS header using 64-bit
#    integers, the METIS header (with 32-bit indices, as used by mfem) needs to
#    be before SuiteSparse.
set(MFEM_TPLS OPENMP HYPRE BLAS LAPACK SuperLUDist METIS SuiteSparse SUNDIALS
    PETSC SLEPC MESQUITE MUMPS STRUMPACK AXOM FMS CONDUIT Ginkgo GNUTLS GSLIB
    NETCDF MPFR PUMI HIOP POSIXCLOCKS MFEMBacktrace ZLIB OCCA CEED RAJA UMPIRE
    ADIOS2 CUBLAS CUSPARSE MKL_CPARDISO AMGX CALIPER CODIPACK BENCHMARK PARELAG
    MPI_CXX HIP HIPSPARSE MOONOLITH BLITZ ALGOIM ENZYME)

# Add all *_FOUND libraries in the variable TPL_LIBRARIES.
set(TPL_LIBRARIES "")
set(TPL_INCLUDE_DIRS "")
foreach(TPL IN LISTS MFEM_TPLS)
  if (${TPL}_FOUND)
    message(STATUS "MFEM: using package ${TPL}")
    list(APPEND TPL_LIBRARIES ${${TPL}_LIBRARIES})
    list(APPEND TPL_INCLUDE_DIRS ${${TPL}_INCLUDE_DIRS})
  endif()
endforeach(TPL)
list(REMOVE_DUPLICATES TPL_LIBRARIES)
list(REMOVE_DUPLICATES TPL_INCLUDE_DIRS)
# message(STATUS "TPL_INCLUDE_DIRS = ${TPL_INCLUDE_DIRS}")

if (OPENMP_FOUND)
  message(STATUS "MFEM: using package OpenMP")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
  if (MFEM_USE_CUDA)
    set(CMAKE_CUDA_FLAGS "${CMAKE_CUDA_FLAGS} -Xcompiler=${OpenMP_CXX_FLAGS}")
  endif()
endif()

message(STATUS "MFEM build type: CMAKE_BUILD_TYPE = ${CMAKE_BUILD_TYPE}")
message(STATUS "MFEM version: v${MFEM_VERSION_STRING}")
message(STATUS "MFEM git string: ${MFEM_GIT_STRING}")

#-------------------------------------------------------------------------------
# Define and configure the MFEM library
#-------------------------------------------------------------------------------

# Headers and sources
set(SOURCES "")
set(HEADERS "")
set(MFEM_SOURCE_DIRS general linalg mesh fem)

if(MFEM_USE_MOONOLITH)
  set(MFEM_SOURCE_DIRS ${MFEM_SOURCE_DIRS} fem/moonolith)
endif()

foreach(DIR IN LISTS MFEM_SOURCE_DIRS)
  add_subdirectory(${DIR})
endforeach()

if (MFEM_USE_CUDA)
  set_source_files_properties(${SOURCES} PROPERTIES LANGUAGE CUDA)
endif()

add_subdirectory(config)
set(MASTER_HEADERS
  ${PROJECT_SOURCE_DIR}/mfem.hpp
  ${PROJECT_SOURCE_DIR}/mfem-performance.hpp)

set(_lib_path "${CMAKE_INSTALL_PREFIX}/lib")
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH ON CACHE BOOL "")
set(CMAKE_INSTALL_RPATH "${_lib_path}" CACHE PATH "")
set(CMAKE_INSTALL_NAME_DIR "${_lib_path}" CACHE PATH "")

set(MFEM_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} CACHE PATH
    "The MFEM source directory" FORCE)
set(MFEM_INSTALL_DIR ${CMAKE_INSTALL_PREFIX} CACHE PATH
    "The MFEM install directory" FORCE)

# Declaring the library
mfem_add_library(mfem ${SOURCES} ${HEADERS} ${MASTER_HEADERS})
# message(STATUS "TPL_LIBRARIES = ${TPL_LIBRARIES}")
target_link_libraries(mfem PUBLIC ${TPL_LIBRARIES})
if (MINGW)
  target_link_libraries(mfem PRIVATE ws2_32)
endif()
if (MSVC)
  target_compile_options(mfem PUBLIC "/wd4819")
endif()
message(STATUS "TPL_INCLUDE_DIRS = ${TPL_INCLUDE_DIRS}")
target_include_directories(mfem
  PUBLIC
    $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
    ${TPL_INCLUDE_DIRS})
set_target_properties(mfem PROPERTIES VERSION "${mfem_VERSION}")
set_target_properties(mfem PROPERTIES SOVERSION "${mfem_VERSION}")

# If building out-of-source, define MFEM_CONFIG_FILE to point to the config file
# inside the build directory.
if (NOT ("${PROJECT_SOURCE_DIR}" STREQUAL "${PROJECT_BINARY_DIR}"))
  target_compile_definitions(mfem PRIVATE
    "MFEM_CONFIG_FILE=\"${PROJECT_BINARY_DIR}/config/_config.hpp\"")
endif()

# Generate configuration file in the build directory: config/_config.hpp.
configure_file(
  "${PROJECT_SOURCE_DIR}/config/cmake/config.hpp.in"
  "${PROJECT_BINARY_DIR}/config/_config.hpp")

# Create substitute mfem.hpp and mfem-performance.hpp in the build directory,
# if it is different from the source directory.
if (NOT ("${PROJECT_SOURCE_DIR}" STREQUAL "${PROJECT_BINARY_DIR}"))
  foreach(Header mfem.hpp mfem-performance.hpp)
    message(STATUS
      "Writing substitute header --> \"${Header}\"")
    file(WRITE "${PROJECT_BINARY_DIR}/${Header}"
"// Auto-generated file.
#define MFEM_CONFIG_FILE \"${PROJECT_BINARY_DIR}/config/_config.hpp\"
#include \"${PROJECT_SOURCE_DIR}/${Header}\"
")
    # This version will be installed in the top include directory:
    file(WRITE "${PROJECT_BINARY_DIR}/InstallHeaders/${Header}"
"// Auto-generated file.
#include \"mfem/${Header}\"
")
  endforeach()
endif()

set(MFEM_CUSTOM_TARGET_PREFIX CACHE STRING "")

#-------------------------------------------------------------------------------
# Examples, miniapps, benchmarks and testing
#-------------------------------------------------------------------------------

# Enable testing and benchmarks if required
if (MFEM_ENABLE_TESTING)
  enable_testing()
  set(MFEM_ALL_TESTS_TARGET_NAME tests)
  add_mfem_target(${MFEM_ALL_TESTS_TARGET_NAME} OFF)
  add_subdirectory(tests EXCLUDE_FROM_ALL)

  # Create a target for all benchmarks and, optionally, enable it.
  set(MFEM_ALL_BENCHMARKS_TARGET_NAME benchmarks)
  add_mfem_target(${MFEM_ALL_BENCHMARKS_TARGET_NAME}
                  ${MFEM_ENABLE_GOOGLE_BENCHMARKS})
  add_subdirectory(tests/benchmarks EXCLUDE_FROM_ALL)
endif()

# Define a target that all examples and miniapps will depend on.
set(MFEM_EXEC_PREREQUISITES_TARGET_NAME exec_prerequisites)
add_custom_target(${MFEM_EXEC_PREREQUISITES_TARGET_NAME})

# Create a target for all examples and, optionally, enable it.
set(MFEM_ALL_EXAMPLES_TARGET_NAME examples)
add_mfem_target(${MFEM_ALL_EXAMPLES_TARGET_NAME} ${MFEM_ENABLE_EXAMPLES})
if (MFEM_ENABLE_EXAMPLES)
  add_subdirectory(examples) #install examples if enabled
else()
  add_subdirectory(examples EXCLUDE_FROM_ALL)
endif()

# Create a target for all miniapps and, optionally, enable it.
set(MFEM_ALL_MINIAPPS_TARGET_NAME miniapps)
add_mfem_target(${MFEM_ALL_MINIAPPS_TARGET_NAME} ${MFEM_ENABLE_MINIAPPS})
add_subdirectory(miniapps EXCLUDE_FROM_ALL)

# Target to build all executables, i.e. everything.
add_custom_target(exec)
add_dependencies(exec
  ${MFEM_ALL_BENCHMARKS_TARGET_NAME}
  ${MFEM_ALL_EXAMPLES_TARGET_NAME}
  ${MFEM_ALL_MINIAPPS_TARGET_NAME}
  ${MFEM_ALL_TESTS_TARGET_NAME})
# Here, we want to "add_dependencies(test exec)". However, dependencies for
# 'test' (and other built-in targets) can not be added with add_dependencies():
#  - https://gitlab.kitware.com/cmake/cmake/issues/8438
#  - https://cmake.org/Bug/view.php?id=8438

# Add a target to copy the mfem data directory to the build directory
add_custom_command(OUTPUT data_is_copied
  COMMAND ${CMAKE_COMMAND} -E copy_directory ${PROJECT_SOURCE_DIR}/data data
  COMMAND ${CMAKE_COMMAND} -E touch data_is_copied
  COMMENT "Copying the data directory ...")
add_custom_target(copy_data DEPENDS data_is_copied)
# Add 'copy_data' as a prerequisite for all executables, if the source and the
# build directories are not the same.
if (NOT ("${PROJECT_SOURCE_DIR}" STREQUAL "${PROJECT_BINARY_DIR}"))
  add_dependencies(${MFEM_EXEC_PREREQUISITES_TARGET_NAME} copy_data)
endif()

# Add 'check' target - quick test
set(MFEM_CHECK_TARGET_NAME ${MFEM_CUSTOM_TARGET_PREFIX}check)
if (NOT MFEM_USE_MPI)
  add_custom_target(${MFEM_CHECK_TARGET_NAME}
    ${CMAKE_CTEST_COMMAND} -R \"^ex1_ser\" -C ${CMAKE_CFG_INTDIR}
    USES_TERMINAL)
  add_dependencies(${MFEM_CHECK_TARGET_NAME} ex1)
else()
  add_custom_target(${MFEM_CHECK_TARGET_NAME}
    ${CMAKE_CTEST_COMMAND} -R \"^ex1p\" -C ${CMAKE_CFG_INTDIR}
    USES_TERMINAL)
  add_dependencies(${MFEM_CHECK_TARGET_NAME} ex1p)
endif()

#-------------------------------------------------------------------------------
# Documentation
#-------------------------------------------------------------------------------
add_subdirectory(doc)

#-------------------------------------------------------------------------------
# Installation
#-------------------------------------------------------------------------------

message(STATUS "CMAKE_INSTALL_PREFIX = ${CMAKE_INSTALL_PREFIX}")
set(INSTALL_INCLUDE_DIR include
  CACHE PATH "Relative path for installing header files.")
set(INSTALL_LIB_DIR lib
  CACHE PATH "Relative path for installing the library.")
# other options: "share/mfem/cmake", "lib/mfem/cmake"
set(INSTALL_CMAKE_DIR lib/cmake/mfem
  CACHE PATH "Relative path for installing cmake config files.")

target_include_directories(mfem
  PUBLIC
    $<INSTALL_INTERFACE:${INSTALL_INCLUDE_DIR}>)

# The 'install' target will not depend on 'all'.
# set(CMAKE_SKIP_INSTALL_ALL_DEPENDENCY TRUE)

set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME Development)

# Install the library
install(TARGETS ${PROJECT_NAME}
  EXPORT ${PROJECT_NAME_UC}Targets
  DESTINATION ${INSTALL_LIB_DIR})

# Install the master headers
foreach(Header mfem.hpp mfem-performance.hpp)
  install(FILES ${PROJECT_BINARY_DIR}/InstallHeaders/${Header}
    DESTINATION ${INSTALL_INCLUDE_DIR})
endforeach()
install(FILES ${MASTER_HEADERS} DESTINATION ${INSTALL_INCLUDE_DIR}/mfem)

# Install the headers; currently, the miniapps headers are excluded
install(DIRECTORY ${MFEM_SOURCE_DIRS}
  DESTINATION ${INSTALL_INCLUDE_DIR}/mfem
  FILES_MATCHING PATTERN "*.hpp")

# Install the okl files
if (MFEM_USE_OCCA)
  install(DIRECTORY ${MFEM_SOURCE_DIRS}
    DESTINATION ${INSTALL_INCLUDE_DIR}/mfem
    FILES_MATCHING PATTERN "*.okl")
endif()

# Install the libCEED files
if (MFEM_USE_CEED)
  install(DIRECTORY ${MFEM_SOURCE_DIRS}
    DESTINATION ${INSTALL_INCLUDE_DIR}/mfem
    FILES_MATCHING PATTERN "fem/ceed/integrators/*/*.h")
endif()

# Install ${HEADERS}
# ---
# foreach (HDR ${HEADERS})
#   file(RELATIVE_PATH REL_HDR ${PROJECT_SOURCE_DIR} ${HDR})
#   get_filename_component(DIR ${REL_HDR} PATH)
#   install(FILES ${REL_HDR} DESTINATION ${INSTALL_INCLUDE_DIR}/${DIR})
# endforeach()

# Install the configuration header files
install(FILES ${PROJECT_BINARY_DIR}/config/_config.hpp
  DESTINATION ${INSTALL_INCLUDE_DIR}/mfem/config
  RENAME config.hpp)

install(FILES ${PROJECT_SOURCE_DIR}/config/tconfig.hpp
  DESTINATION ${INSTALL_INCLUDE_DIR}/mfem/config)

# Package the whole thing up nicely
include(CMakePackageConfigHelpers)

# Add all targets to the build-tree export set
export(TARGETS ${PROJECT_NAME}
  FILE "${PROJECT_BINARY_DIR}/MFEMTargets.cmake")

# Export the package for use from the build-tree (this registers the build-tree
# with the CMake user package registry.)
# TODO: How do we register the install-tree? Replacing the build-tree?
export(PACKAGE ${PROJECT_NAME})

# This is the build-tree version
set(INCLUDE_INSTALL_DIRS ${PROJECT_BINARY_DIR} ${TPL_INCLUDE_DIRS})
set(LIB_INSTALL_DIR ${PROJECT_BINARY_DIR})
configure_package_config_file(config/cmake/MFEMConfig.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}/MFEMConfig.cmake
  INSTALL_DESTINATION ${CMAKE_CURRENT_BINARY_DIR}
  PATH_VARS INCLUDE_INSTALL_DIRS LIB_INSTALL_DIR)

# This is the version that will be installed
set(INCLUDE_INSTALL_DIRS ${INSTALL_INCLUDE_DIR}  ${TPL_INCLUDE_DIRS})
set(LIB_INSTALL_DIR ${INSTALL_LIB_DIR})
configure_package_config_file(config/cmake/MFEMConfig.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/MFEMConfig.cmake
  INSTALL_DESTINATION ${INSTALL_CMAKE_DIR}
  PATH_VARS INCLUDE_INSTALL_DIRS LIB_INSTALL_DIR)

# Write the version file (same for build and install tree)
write_basic_package_version_file(
  ${CMAKE_CURRENT_BINARY_DIR}/MFEMConfigVersion.cmake
  VERSION ${${PROJECT_NAME}_VERSION}
  COMPATIBILITY SameMajorVersion )

# Install the config files
install(FILES
  ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/MFEMConfig.cmake
  ${CMAKE_CURRENT_BINARY_DIR}/MFEMConfigVersion.cmake
  DESTINATION ${INSTALL_CMAKE_DIR})

# Install the export set for use with the install-tree
install(EXPORT ${PROJECT_NAME_UC}Targets
    DESTINATION ${INSTALL_CMAKE_DIR})

#-------------------------------------------------------------------------------
# Create 'config.mk' from 'config.mk.in' for the build and install locations and
# define install rules for 'config.mk' and 'test.mk'
#-------------------------------------------------------------------------------

mfem_export_mk_files()