mlpack/CMakeLists.txt

cmake_minimum_required(VERSION 2.8.5)
project(mlpack C CXX)

# First, define all the compilation options.
# We default to debugging mode for developers.
option(DEBUG "Compile with debugging information." OFF)
option(PROFILE "Compile with profiling information." OFF)
option(ARMA_EXTRA_DEBUG "Compile with extra Armadillo debugging symbols." OFF)
option(MATLAB_BINDINGS "Compile MATLAB bindings if MATLAB is found." OFF)
option(TEST_VERBOSE "Run test cases with verbose output." OFF)
option(BUILD_TESTS "Build tests." ON)
option(BUILD_CLI_EXECUTABLES "Build command-line executables." ON)
option(BUILD_PYTHON_BINDINGS "Build Python bindings." ON)
option(BUILD_SHARED_LIBS
    "Compile shared libraries (if OFF, static libraries are compiled)." ON)
option(BUILD_WITH_COVERAGE
    "Build with support for code coverage tools (gcc only)." OFF)
option(MATHJAX
    "Use MathJax for HTML Doxygen output (disabled by default)." OFF)
option(FORCE_CXX11
    "Don't check that the compiler supports C++11, just assume it.  Make sure to specify any necessary flag to enable C++11 as part of CXXFLAGS."
    OFF)
enable_testing()

# Ensure that we have a C++11 compiler.  In newer versions of CMake, this is
# done with target_compile_features() when the mlpack library target is added in
# src/mlpack/CMakeLists.txt.
if ((${CMAKE_MAJOR_VERSION} LESS 3 OR
    (${CMAKE_MAJOR_VERSION} EQUAL 3 AND ${CMAKE_MINOR_VERSION} LESS 1))
    AND NOT FORCE_CXX11)
  # Older versions of CMake do not support target_compile_features(), so we have
  # to use something kind of hacky.
  include(CMake/CXX11.cmake)
  check_for_cxx11_compiler(HAS_CXX11)
  if(NOT HAS_CXX11)
    message(FATAL_ERROR "No C++11 compiler available!")
  endif()
  enable_cxx11()
endif ()
# Otherwise, we may have to set the C++11 mode after the mlpack target is
# defined.

# Include modules in the CMake directory.
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/CMake")

# This is as of yet unused.
#option(PGO "Use profile-guided optimization if not a debug build" ON)

# Set the CFLAGS and CXXFLAGS depending on the options the user specified.
# Only GCC-like compilers support -Wextra, and other compilers give tons of
# output for -Wall, so only -Wall and -Wextra on GCC.
if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -ftemplate-depth=1000")
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra")
endif()

# These support libraries are used if we need to link against something
# specific.  This list is a subset of MLPACK_LIBRARIES.
set(COMPILER_SUPPORT_LIBRARIES "")

# If using clang, we have to link against libc++ depending on the
# OS (at least on some systems). Further, gcc sometimes optimizes calls to
# math.h functions, making -lm unnecessary with gcc, but it may still be
# necessary with clang.
if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
  if (APPLE)
    # Detect OS X version. Use '/usr/bin/sw_vers -productVersion' to
    # extract V from '10.V.x'.
    exec_program(/usr/bin/sw_vers ARGS
        -productVersion OUTPUT_VARIABLE MACOSX_VERSION_RAW)
    string(REGEX REPLACE
        "10\\.([0-9]+).*" "\\1"
        MACOSX_VERSION
        "${MACOSX_VERSION_RAW}")

     # OSX Lion (10.7) and OS X Mountain Lion (10.8) doesn't automatically
     # select the right stdlib.
    if(${MACOSX_VERSION} LESS 9)
      set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stdlib=libc++")
      set(CMAKE_SHARED_LINKER_FLAGS
          "${CMAKE_SHARED_LINKER_FLAGS} -stdlib=libc++")
      set(CMAKE_MODULE_LINKER_FLAGS
          "${CMAKE_MODULE_LINKER_FLAGS} -stdlib=libc++")
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
     endif()
  endif()

  # Link everything with -lm.
  set(COMPILER_SUPPORT_LIBRARIES ${COMPILER_SUPPORT_LIBRARIES} "m")
  set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} "m")
endif()

# Setup build for test coverage
if(BUILD_WITH_COVERAGE)
  # Currently coverage only works with GNU g++
  if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
    # Find gcov and lcov
    find_program(GCOV gcov)
    find_program(LCOV lcov)

    if(NOT GCOV)
      message(FATAL_ERROR
          "gcov not found! gcov is required when BUILD_WITH_COVERAGE=ON.")
    endif()

    set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} "supc++")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage -fno-inline -fno-inline-small-functions -fno-default-inline -fprofile-arcs -fkeep-inline-functions")
    message(STATUS "Adding debug compile options for code coverage.")
    # Remove optimizations for better line coverage
    set(DEBUG ON)

    if(LCOV)
      configure_file(CMake/mlpack_coverage.in mlpack_coverage @ONLY)
      add_custom_target(mlpack_coverage DEPENDS mlpack_test COMMAND ${PROJECT_BINARY_DIR}/mlpack_coverage)
    else()
      message(WARNING "'lcov' not found; local coverage report is disabled. "
          "Install 'lcov' and rerun cmake to generate local coverage report.")
    endif()
  else()
    message(FATAL_ERROR "BUILD_WITH_COVERAGE can only work with GNU environment.")
  endif()
endif()

# For clock_gettime().
if (UNIX AND NOT APPLE)
  set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} "rt")
endif ()

# Debugging CFLAGS.  Turn optimizations off; turn debugging symbols on.
if(DEBUG)
  if (NOT MSVC)
    add_definitions(-DDEBUG)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O0 -ftemplate-backtrace-limit=0")
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -g -O0")
  else()
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /bigobj")
  endif()

  # mlpack uses it's own mlpack::backtrace class based on Binary File Descriptor
  # <bfd.h> and linux Dynamic Loader <libdl.h> and more portable version in future
  if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
    find_package(Bfd)
    find_package(LibDL)
    if(LIBBFD_FOUND AND LIBDL_FOUND)
      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -rdynamic")
      set(MLPACK_INCLUDE_DIRS ${MLPACK_INCLUDE_DIRS} ${LIBBFD_INCLUDE_DIRS}
          ${LIBDL_INCLUDE_DIRS})
      set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} ${LIBBFD_LIBRARIES}
          ${LIBDL_LIBRARIES})
      add_definitions(-DHAS_BFD_DL)
    else()
      message(WARNING "No libBFD and/or libDL has been found!")
    endif()
  endif()
else()
  add_definitions(-DARMA_NO_DEBUG)
  add_definitions(-DNDEBUG)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -O3")
endif()

# Profiling CFLAGS.  Turn profiling information on.
if(CMAKE_COMPILER_IS_GNUCC AND PROFILE)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pg")
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pg")
  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pg")
endif()

# If the user asked for running test cases with verbose output, turn that on.
if(TEST_VERBOSE)
  add_definitions(-DTEST_VERBOSE)
endif()

# If the user asked for extra Armadillo debugging output, turn that on.
if(ARMA_EXTRA_DEBUG)
  add_definitions(-DARMA_EXTRA_DEBUG)
endif()

# Now, find the libraries we need to compile against.  Several variables can be
# set to manually specify the directory in which each of these libraries
# resides.
#   ARMADILLO_LIBRARY - location of libarmadillo.so / armadillo.lib
#   ARMADILLO_INCLUDE_DIR - directory containing <armadillo>
#   ARMADILLO_INCLUDE_DIRS - directories necessary for Armadillo includes
#   BOOST_ROOT - root of Boost installation
#   BOOST_INCLUDEDIR - include directory for Boost
#   BOOST_LIBRARYDIR - library directory for Boost
#   MATHJAX_ROOT - root of MathJax installation

find_package(Armadillo 4.200.0 REQUIRED)

# If Armadillo was compiled without ARMA_64BIT_WORD and we are on a 64-bit
# system (where size_t will be 64 bits), suggest to the user that they should
# compile Armadillo with 64-bit words.  Note that with Armadillo 5.000.0 and
# newer, ARMA_64BIT_WORD is enabled by default.
if(CMAKE_SIZEOF_VOID_P EQUAL 8)
  # Check the version, to see if ARMA_64BIT_WORD is enabled by default.
  set(ARMA_HAS_64BIT_WORD 0)
  if(NOT (${ARMADILLO_VERSION_MAJOR} LESS 5))
    set(ARMA_HAS_64BIT_WORD 1)
  else()
    # Can we open the configuration file?  If not, issue a warning.
    if(NOT EXISTS "${ARMADILLO_INCLUDE_DIR}/armadillo_bits/config.hpp")
      message(WARNING "Armadillo configuration file "
          "(${ARMADILLO_INCLUDE_DIR}/armadillo_bits/config.hpp) does not exist!")
    else()
      # We are on a 64-bit system.  Does Armadillo have ARMA_64BIT_WORD enabled?
      file(READ "${ARMADILLO_INCLUDE_DIR}/armadillo_bits/config.hpp" ARMA_CONFIG)
      string(REGEX MATCH
          "[\r\n][ ]*#define ARMA_64BIT_WORD"
          ARMA_HAS_64BIT_WORD_PRE
          "${ARMA_CONFIG}")

      string(LENGTH "${ARMA_HAS_64BIT_WORD_PRE}" ARMA_HAS_64BIT_WORD)
    endif()
  endif()

  if(ARMA_HAS_64BIT_WORD EQUAL 0)
    message(WARNING "This is a 64-bit system, but Armadillo was compiled "
        "without 64-bit index support.  Consider recompiling Armadillo with "
        "ARMA_64BIT_WORD to enable 64-bit indices (large matrix support). "
        "mlpack will still work without ARMA_64BIT_WORD defined, but will not "
        "scale to matrices with more than 4 billion elements.")
  endif()
else()
  # If we are on a 32-bit system, we must manually specify the size of the word
  # to be 32 bits, since otherwise Armadillo will produce a warning that it is
  # disabling 64-bit support.
  if (CMAKE_SIZEOF_VOID_P EQUAL 4)
    add_definitions(-DARMA_32BIT_WORD)
  endif ()
endif()

# On Windows, Armadillo should be using LAPACK and BLAS but we still need to
# link against it.  We don't want to use the FindLAPACK or FindBLAS modules
# because then we are required to have a FORTRAN compiler (argh!) so we will try
# and find LAPACK and BLAS ourselves, using a slightly modified variant of the
# script Armadillo uses to find these.
if (WIN32)
  find_library(LAPACK_LIBRARY
      NAMES lapack liblapack lapack_win32_MT lapack_win32
      PATHS "C:/Program Files/Armadillo"
      PATH_SUFFIXES "examples/lib_win32/")

  if (NOT LAPACK_LIBRARY)
    message(FATAL_ERROR "Cannot find LAPACK library (.lib)!")
  endif ()

  find_library(BLAS_LIBRARY
      NAMES blas libblas blas_win32_MT blas_win32
      PATHS "C:/Program Files/Armadillo"
      PATH_SUFFIXES "examples/lib_win32/")

  if (NOT BLAS_LIBRARY)
    message(FATAL_ERROR "Cannot find BLAS library (.lib)!")
  endif ()

  # Piggyback LAPACK and BLAS linking into Armadillo link.
  set(ARMADILLO_LIBRARIES
       ${ARMADILLO_LIBRARIES} ${BLAS_LIBRARY} ${LAPACK_LIBRARY})
endif ()

# Include directories for the previous dependencies.
set(MLPACK_INCLUDE_DIRS ${MLPACK_INCLUDE_DIRS} ${ARMADILLO_INCLUDE_DIRS})
set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} ${ARMADILLO_LIBRARIES})

# Unfortunately this configuration variable is necessary and will need to be
# updated as time goes on and new versions are released.
set(Boost_ADDITIONAL_VERSIONS
  "1.49.0" "1.50.0" "1.51.0" "1.52.0" "1.53.0" "1.54.0" "1.55.0")
find_package(Boost 1.49
    COMPONENTS
      program_options
      unit_test_framework
      serialization
    REQUIRED
)

link_directories(${Boost_LIBRARY_DIRS})

# In Visual Studio, automatic linking is performed, so we don't need to worry
# about it.  Clear the list of libraries to link against and let Visual Studio
# handle it.
if (MSVC)
  link_directories(${Boost_LIBRARY_DIRS})
  set(Boost_LIBRARIES "")
endif ()

set(MLPACK_INCLUDE_DIRS ${MLPACK_INCLUDE_DIRS} ${Boost_INCLUDE_DIRS})
set(MLPACK_LIBRARIES ${MLPACK_LIBRARIES} ${Boost_LIBRARIES})
set(MLPACK_LIBRARY_DIRS ${MLPACK_LIBRARY_DIRS} ${Boost_LIBRARY_DIRS})

# For Boost testing framework (will have no effect on non-testing executables).
# This specifies to Boost that we are dynamically linking to the Boost test
# library.
add_definitions(-DBOOST_TEST_DYN_LINK)

# Detect OpenMP support in a compiler. If the compiler supports OpenMP, flags
# to compile with OpenMP are returned and added and the HAS_OPENMP definition is
# added for compilation.
#
# This way we can skip calls to functions defined in omp.h with code like:
# #ifdef HAS_OPENMP
# {
#   ... openMP code here ...
# }
# #endif
find_package(OpenMP)
if (OPENMP_FOUND)
  add_definitions(-DHAS_OPENMP)
  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
else ()
  # Disable warnings for all the unknown OpenMP pragmas.
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-unknown-pragmas")
endif ()

# Create a 'distclean' target in case the user is using an in-source build for
# some reason.
include(CMake/TargetDistclean.cmake OPTIONAL)

include_directories(${CMAKE_SOURCE_DIR})
include_directories(${MLPACK_INCLUDE_DIRS})

# On Windows, things end up under Debug/ or Release/.
if (WIN32)
  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
else ()
  # If not on Windows, put them under more standard UNIX-like places.  This is
  # necessary, otherwise they would all end up in
  # ${CMAKE_BINARY_DIR}/src/mlpack/methods/... or somewhere else random like
  # that.
  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/)
  set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin/)
  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib/)
endif ()

# Determine whether or not this is a git repository, so that we can set the
# version number if necessary.
find_package(Git)
set (USING_GIT "NO")
if (GIT_FOUND)
  # Run 'git rev-parse HEAD' to find out if this is a working copy. If the
  # return code is not 0, then it isn't.
  execute_process(COMMAND ${GIT_EXECUTABLE} rev-parse HEAD
      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
      OUTPUT_VARIABLE MLPACK_TMP_REV_INFO
      ERROR_VARIABLE MLPACK_TMP_REV_INFO_ERROR
      RESULT_VARIABLE MLPACK_TMP_REV_INFO_RESULT
      OUTPUT_STRIP_TRAILING_WHITESPACE)
  if (${MLPACK_TMP_REV_INFO_RESULT} EQUAL 0)
    set (USING_GIT "YES")
    add_definitions(-DMLPACK_GIT_VERSION)
    include(CMake/CreateGitVersionHeader.cmake)

    add_custom_target(mlpack_gitversion ALL
        COMMAND ${CMAKE_COMMAND} -P CMake/CreateGitVersionHeader.cmake
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
        COMMENT "Updating gitversion.hpp (if necessary)")
  # Add gitversion.hpp to the list of sources.
  set(MLPACK_SRCS ${MLPACK_SRCS}
      "${CMAKE_CURRENT_SOURCE_DIR}/src/mlpack/core/util/gitversion.hpp")
  endif ()
endif ()

# Create a target to generate arma_config.hpp, which is used to warn the user
# when they are doing something stupid when linking something against mlpack.
include(CMake/CreateArmaConfigInfo.cmake)

add_custom_target(mlpack_arma_config ALL
    COMMAND ${CMAKE_COMMAND}
        -D ARMADILLO_INCLUDE_DIR="${ARMADILLO_INCLUDE_DIR}"
        -D ARMADILLO_VERSION_MAJOR="${ARMADILLO_VERSION_MAJOR}"
        -P CMake/CreateArmaConfigInfo.cmake
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    COMMENT "Updating arma_config.hpp (if necessary)")
set(MLPACK_SRCS ${MLPACK_SRCS}
    "${CMAKE_CURRENT_SOURCE_DIR}/src/mlpack/core/util/arma_config.hpp")

# Recurse into the rest of the project.
add_subdirectory(src/mlpack)

# If we need to keep gitversion.hpp up to date, then make sure the mlpack target
# depends on it.
if (USING_GIT STREQUAL "YES")
  add_dependencies(mlpack mlpack_gitversion)
endif ()

# Make the mlpack_arma_config target depend on mlpack (we couldn't do this
# before the add_subdirectory() call because the mlpack target didn't exist
# before that).
add_dependencies(mlpack mlpack_arma_config)

# Make a target to generate the documentation.  If Doxygen isn't installed, then
# I guess this option will just be unavailable.
find_package(Doxygen)
if (DOXYGEN_FOUND)
  if (MATHJAX)
    find_package(MathJax)
    if (NOT MATHJAX_FOUND)
      message(STATUS "Using MathJax at the MathJax Content Delivery Network. "
          "Be careful, formulas will not be shown without the internet.")
    endif ()
  endif ()
  # Preprocess the Doxyfile.  This is done before 'make doc'.
  add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/Doxyfile
      PRE_BUILD
      COMMAND ${CMAKE_COMMAND}
          -D DESTDIR="${CMAKE_BINARY_DIR}"
          -D MATHJAX="${MATHJAX}"
          -D MATHJAX_FOUND="${MATHJAX_FOUND}"
          -D MATHJAX_PATH="${MATHJAX_PATH}"
          -P "${CMAKE_CURRENT_SOURCE_DIR}/CMake/GenerateDoxyfile.cmake"
      WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
      DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/Doxyfile"
      COMMENT "Creating Doxyfile to generate Doxygen documentation"
  )

  # Generate documentation.
  add_custom_target(doc
      COMMAND "${DOXYGEN_EXECUTABLE}" "${CMAKE_BINARY_DIR}/Doxyfile"
      DEPENDS "${CMAKE_BINARY_DIR}/Doxyfile"
      WORKING_DIRECTORY "${CMAKE_BINARY_DIR}"
      COMMENT "Generating API documentation with Doxygen"
  )

  install(DIRECTORY ${CMAKE_BINARY_DIR}/doc/html
      DESTINATION share/doc/mlpack
      COMPONENT doc
      OPTIONAL
  )
endif ()

# Make a target to generate the man page documentation, but only if we are on a
# UNIX-like system.
if (UNIX)
  find_program(TXT2MAN txt2man)

  # It's not a requirement that we make man pages.
  if (NOT TXT2MAN)
    message(WARNING "txt2man not found; man pages will not be generated.")
  else ()
    # We have the tools.  We can make them.
    add_custom_target(man ALL
        ${CMAKE_CURRENT_SOURCE_DIR}/CMake/allexec2man.sh
            ${CMAKE_CURRENT_SOURCE_DIR}/CMake/exec2man.sh
            ${CMAKE_BINARY_DIR}/share/man
        WORKING_DIRECTORY
          ${CMAKE_BINARY_DIR}/bin
        DEPENDS
          mlpack_adaboost
          mlpack_approx_kfn
          mlpack_kfn
          mlpack_knn
          mlpack_krann
          mlpack_cf
          mlpack_dbscan
          mlpack_decision_stump
          mlpack_decision_tree
          mlpack_det
          mlpack_emst
          mlpack_fastmks
          mlpack_gmm_train
          mlpack_gmm_probability
          mlpack_gmm_generate
          mlpack_hmm_generate
          mlpack_hmm_loglik
          mlpack_hmm_train
          mlpack_hmm_viterbi
          mlpack_hoeffding_tree
          mlpack_kernel_pca
          mlpack_kmeans
          mlpack_lars
          mlpack_linear_regression
          mlpack_local_coordinate_coding
          mlpack_logistic_regression
          mlpack_lsh
          mlpack_mean_shift
          mlpack_nbc
          mlpack_nca
          mlpack_nmf
          mlpack_pca
          mlpack_perceptron
          mlpack_radical
          mlpack_range_search
          mlpack_softmax_regression
          mlpack_sparse_coding
        COMMENT "Generating man pages from built executables."
    )

    # Set the rules to install the documentation.
    install(DIRECTORY ${CMAKE_BINARY_DIR}/share/man/
        DESTINATION share/man/man1/)
  endif ()
endif ()

# Create the pkg-config file, if we have pkg-config.
find_package(PkgConfig)
if (PKG_CONFIG_FOUND)
  # mlpack.pc must be generated as a separate target, otherwise it is possible
  # that the given version could be out of date.  We don't need to worry about
  # the library or include directories changing, because CMake will re-run this
  # portion of the code whenever any of those changes.  But the version must be
  # re-extracted every time the library is built.

  # So, we have to parse our list of library directories, libraries, and include
  # directories in order to get the correct line to give to pkg-config.
  # Next, adapt the list of include directories.
  foreach (incldir ${MLPACK_INCLUDE_DIRS})
    # Filter out some obviously unnecessary directories.
    if (NOT "${incldir}" STREQUAL "/usr/include")
      set(MLPACK_INCLUDE_DIRS_STRING "${MLPACK_INCLUDE_DIRS_STRING}
          -I${incldir}")
    endif ()
  endforeach ()
  # Add the install directory too.
  set(MLPACK_INCLUDE_DIRS_STRING
      "${MLPACK_INCLUDE_DIRS_STRING} -I${CMAKE_INSTALL_PREFIX}/include/")

  # Create the list of link directories.
  set(MLPACK_LIBRARIES_LIST)
  foreach (linkdir ${MLPACK_LIBRARY_DIRS})
    list(APPEND MLPACK_LIBRARIES_LIST "-L${linkdir}")
  endforeach ()

  foreach(lib ${MLPACK_LIBRARIES})
    string(SUBSTRING "${lib}" 0 1 first)
    if ("${first}" STREQUAL "/")
      # We need to split the directory and the library.
      string(REGEX REPLACE "(.*/)[^/]*$" "\\1" library_dir "${lib}")
      string(REGEX REPLACE ".*/lib([^/]*).so.*$" "\\1" library_name "${lib}")

      list(APPEND MLPACK_LIBRARIES_LIST "-L${library_dir}")
      list(APPEND MLPACK_LIBRARIES_LIST "-l${library_name}")
    else ()
      list(APPEND MLPACK_LIBRARIES_LIST "-l${lib}")
    endif ()
  endforeach ()
  # Don't forget to add mlpack as a dependency too.
  list(APPEND MLPACK_LIBRARIES_LIST "-L${CMAKE_INSTALL_PREFIX}/lib/")
  list(APPEND MLPACK_LIBRARIES_LIST "-lmlpack")

  # Filter duplicate dependencies and directories.
  list(REMOVE_DUPLICATES MLPACK_LIBRARIES_LIST)

  # Filter out known unnecessary directories.
  list(REMOVE_ITEM MLPACK_LIBRARIES_LIST
      "-L/usr/lib"
      "-L/usr/lib/"
      "-L/usr/lib/x86_64-linux-gnu"
      "-L/usr/lib/x86_64-linux-gnu/"
      "-L/usr/lib/i386-linux-gnu"
      "-L/usr/lib/i386-linux-gnu/")

  string(REPLACE ";" " " MLPACK_LIBRARIES_STRING "${MLPACK_LIBRARIES_LIST}")

  # Do first stage of configuration.
  set(MLPACK_VERSION_STRING "@MLPACK_VERSION_STRING@")
  configure_file(
    ${CMAKE_CURRENT_SOURCE_DIR}/CMake/mlpack.pc.in
    ${CMAKE_BINARY_DIR}/CMake/mlpack.pc.in.partial @ONLY)

  add_custom_target(pkgconfig ALL
      ${CMAKE_COMMAND}
          -P "${CMAKE_CURRENT_SOURCE_DIR}/CMake/GeneratePkgConfig.cmake"
      DEPENDS mlpack_headers
      COMMENT "Generating mlpack.pc (pkg-config) file.")

  # Do we need a different directory?
  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/lib/pkgconfig/mlpack.pc
      DESTINATION lib/pkgconfig/)
endif ()