CMakeLists.txt
author Alpar Juttner <alpar@cs.elte.hu>
Tue, 28 Apr 2015 18:13:42 +0200
changeset 1343 20f95cd51aba
parent 1337 4add05447ca0
parent 1340 f70f688d9ef9
child 1346 f95b18d99843
permissions -rw-r--r--
Merge bugfix #595
     1 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
     2 
     3 IF(POLICY CMP0048) 
     4   CMAKE_POLICY(SET CMP0048 OLD) 
     5 ENDIF(POLICY CMP0048)
     6 
     7 IF(POLICY CMP0043) 
     8   CMAKE_POLICY(SET CMP0043 OLD) 
     9 ENDIF(POLICY CMP0043)
    10 
    11 SET(PROJECT_NAME "LEMON")
    12 PROJECT(${PROJECT_NAME})
    13 
    14 INCLUDE(FindPythonInterp)
    15 INCLUDE(FindWget)
    16 
    17 IF(EXISTS ${PROJECT_SOURCE_DIR}/cmake/version.cmake)
    18   INCLUDE(${PROJECT_SOURCE_DIR}/cmake/version.cmake)
    19 ELSEIF(DEFINED ENV{LEMON_VERSION})
    20   SET(LEMON_VERSION $ENV{LEMON_VERSION} CACHE STRING "LEMON version string.")
    21 ELSE()
    22   EXECUTE_PROCESS(
    23     COMMAND
    24     hg log -r. --template "{latesttag}"
    25     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
    26     OUTPUT_VARIABLE HG_REVISION_TAG
    27     ERROR_QUIET
    28     OUTPUT_STRIP_TRAILING_WHITESPACE
    29   )
    30   EXECUTE_PROCESS(
    31     COMMAND
    32     hg log -r. --template "{latesttagdistance}"
    33     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
    34     OUTPUT_VARIABLE HG_REVISION_DIST
    35     ERROR_QUIET
    36     OUTPUT_STRIP_TRAILING_WHITESPACE
    37   )
    38   EXECUTE_PROCESS(
    39     COMMAND
    40     hg log -r. --template "{node|short}"
    41     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
    42     OUTPUT_VARIABLE HG_REVISION_ID
    43     ERROR_QUIET
    44     OUTPUT_STRIP_TRAILING_WHITESPACE
    45   )
    46 
    47   IF(HG_REVISION_TAG STREQUAL "")
    48     SET(HG_REVISION_ID "hg-tip")
    49   ELSE()
    50     IF(HG_REVISION_TAG STREQUAL "null")
    51       SET(HG_REVISION_TAG "trunk")
    52     ELSEIF(HG_REVISION_TAG MATCHES "^r")
    53       STRING(SUBSTRING ${HG_REVISION_TAG} 1 -1 HG_REVISION_TAG)
    54     ENDIF()
    55     IF(HG_REVISION_DIST STREQUAL "0")
    56       SET(HG_REVISION ${HG_REVISION_TAG})
    57     ELSE()
    58       SET(HG_REVISION
    59 	"${HG_REVISION_TAG}+${HG_REVISION_DIST}-${HG_REVISION_ID}")
    60     ENDIF()
    61   ENDIF()
    62 
    63   SET(LEMON_VERSION ${HG_REVISION} CACHE STRING "LEMON version string.")
    64 ENDIF()
    65 
    66 SET(PROJECT_VERSION ${LEMON_VERSION})
    67 
    68 SET(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
    69 
    70 FIND_PACKAGE(Doxygen)
    71 FIND_PACKAGE(Ghostscript)
    72 
    73 IF(WIN32)
    74   SET(LEMON_WIN32 TRUE)
    75 ENDIF(WIN32)
    76 
    77 SET(LEMON_ENABLE_GLPK YES CACHE STRING "Enable GLPK solver backend.")
    78 SET(LEMON_ENABLE_ILOG YES CACHE STRING "Enable ILOG (CPLEX) solver backend.")
    79 SET(LEMON_ENABLE_COIN YES CACHE STRING "Enable COIN solver backend.")
    80 SET(LEMON_ENABLE_SOPLEX YES CACHE STRING "Enable SoPlex solver backend.")
    81 
    82 IF(LEMON_ENABLE_GLPK) 
    83   FIND_PACKAGE(GLPK 4.33)
    84 ENDIF(LEMON_ENABLE_GLPK)
    85 IF(LEMON_ENABLE_ILOG)
    86   FIND_PACKAGE(ILOG)
    87 ENDIF(LEMON_ENABLE_ILOG)
    88 IF(LEMON_ENABLE_COIN)
    89   FIND_PACKAGE(COIN)
    90 ENDIF(LEMON_ENABLE_COIN)
    91 IF(LEMON_ENABLE_SOPLEX)
    92   FIND_PACKAGE(SOPLEX)
    93 ENDIF(LEMON_ENABLE_SOPLEX)
    94 
    95 IF(GLPK_FOUND)
    96   SET(LEMON_HAVE_LP TRUE)
    97   SET(LEMON_HAVE_MIP TRUE)
    98   SET(LEMON_HAVE_GLPK TRUE)
    99 ENDIF(GLPK_FOUND)
   100 IF(ILOG_FOUND)
   101   SET(LEMON_HAVE_LP TRUE)
   102   SET(LEMON_HAVE_MIP TRUE)
   103   SET(LEMON_HAVE_CPLEX TRUE)
   104 ENDIF(ILOG_FOUND)
   105 IF(COIN_FOUND)
   106   SET(LEMON_HAVE_LP TRUE)
   107   SET(LEMON_HAVE_MIP TRUE)
   108   SET(LEMON_HAVE_CLP TRUE)
   109   SET(LEMON_HAVE_CBC TRUE)
   110 ENDIF(COIN_FOUND)
   111 IF(SOPLEX_FOUND)
   112   SET(LEMON_HAVE_LP TRUE)
   113   SET(LEMON_HAVE_SOPLEX TRUE)
   114 ENDIF(SOPLEX_FOUND)
   115 
   116 IF(ILOG_FOUND)
   117   SET(DEFAULT_LP "CPLEX")
   118   SET(DEFAULT_MIP "CPLEX")
   119 ELSEIF(COIN_FOUND)
   120   SET(DEFAULT_LP "CLP")
   121   SET(DEFAULT_MIP "CBC")
   122 ELSEIF(GLPK_FOUND)
   123   SET(DEFAULT_LP "GLPK")
   124   SET(DEFAULT_MIP "GLPK")
   125 ELSEIF(SOPLEX_FOUND)
   126   SET(DEFAULT_LP "SOPLEX")
   127 ENDIF()
   128 
   129 IF(NOT LEMON_DEFAULT_LP OR
   130     (NOT ILOG_FOUND AND (LEMON_DEFAULT_LP STREQUAL "CPLEX")) OR
   131     (NOT COIN_FOUND AND (LEMON_DEFAULT_LP STREQUAL "CLP")) OR
   132     (NOT GLPK_FOUND AND (LEMON_DEFAULT_LP STREQUAL "GLPK")) OR
   133     (NOT SOPLEX_FOUND AND (LEMON_DEFAULT_LP STREQUAL "SOPLEX")))
   134   SET(LEMON_DEFAULT_LP ${DEFAULT_LP} CACHE STRING
   135     "Default LP solver backend (GLPK, CPLEX, CLP or SOPLEX)" FORCE)
   136 ELSE()
   137   SET(LEMON_DEFAULT_LP ${DEFAULT_LP} CACHE STRING
   138     "Default LP solver backend (GLPK, CPLEX, CLP or SOPLEX)")
   139 ENDIF()
   140 IF(NOT LEMON_DEFAULT_MIP OR
   141     (NOT ILOG_FOUND AND (LEMON_DEFAULT_MIP STREQUAL "CPLEX")) OR
   142     (NOT COIN_FOUND AND (LEMON_DEFAULT_MIP STREQUAL "CBC")) OR
   143     (NOT GLPK_FOUND AND (LEMON_DEFAULT_MIP STREQUAL "GLPK")))
   144   SET(LEMON_DEFAULT_MIP ${DEFAULT_MIP} CACHE STRING
   145     "Default MIP solver backend (GLPK, CPLEX or CBC)" FORCE)
   146 ELSE()
   147   SET(LEMON_DEFAULT_MIP ${DEFAULT_MIP} CACHE STRING
   148     "Default MIP solver backend (GLPK, CPLEX or CBC)")
   149 ENDIF()
   150 
   151 
   152 IF(DEFINED ENV{LEMON_CXX_WARNING})
   153   SET(CXX_WARNING $ENV{LEMON_CXX_WARNING})
   154 ELSE()
   155   IF(CMAKE_COMPILER_IS_GNUCXX)
   156     SET(CXX_WARNING "-Wall -W -Wunused -Wformat=2 -Wctor-dtor-privacy -Wnon-virtual-dtor -Wno-char-subscripts -Wwrite-strings -Wno-char-subscripts -Wreturn-type -Wcast-qual -Wcast-align -Wsign-promo -Woverloaded-virtual -fno-strict-aliasing -Wold-style-cast -Wno-unknown-pragmas")
   157     SET(CMAKE_CXX_FLAGS_DEBUG CACHE STRING "-ggdb")
   158     SET(CMAKE_C_FLAGS_DEBUG CACHE STRING "-ggdb")
   159   ELSEIF(MSVC)
   160     # This part is unnecessary 'casue the same is set by the lemon/core.h.
   161     # Still kept as an example.
   162 
   163     # SET(CXX_WARNING "/wd4250 /wd4267 /wd4355 /wd4503 /wd4800 /wd4996")
   164 
   165     # Suppressed warnings:
   166     # C4250: 'class1' : inherits 'class2::member' via dominance
   167     # C4267: conversion from 'size_t' to 'type', possible loss of data
   168     # C4355: 'this' : used in base member initializer list
   169     # C4503: 'function' : decorated name length exceeded, name was truncated
   170     # C4800: 'type' : forcing value to bool 'true' or 'false'
   171     #        (performance warning)
   172     # C4996: 'function': was declared deprecated
   173   ELSE()
   174     SET(CXX_WARNING "-Wall")
   175   ENDIF()
   176 ENDIF()
   177 SET(LEMON_CXX_WARNING_FLAGS ${CXX_WARNING} CACHE STRING "LEMON warning flags.")
   178 
   179 SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LEMON_CXX_WARNING_FLAGS}")
   180 
   181 IF(MSVC)
   182   SET(CMAKE_CXX_FLAGS "/bigobj ${CMAKE_CXX_FLAGS}")
   183   SET( CMAKE_CXX_FLAGS_MAINTAINER "/WX ${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING
   184     "Flags used by the C++ compiler during maintainer builds."
   185     )
   186   SET( CMAKE_C_FLAGS_MAINTAINER "/WX ${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING
   187     "Flags used by the C compiler during maintainer builds."
   188     )
   189   SET( CMAKE_EXE_LINKER_FLAGS_MAINTAINER
   190     "${CMAKE_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING
   191     "Flags used for linking binaries during maintainer builds."
   192     )
   193   SET( CMAKE_SHARED_LINKER_FLAGS_MAINTAINER
   194     "${CMAKE_SHARED_LINKER_FLAGS_DEBUG}" CACHE STRING
   195     "Flags used by the shared libraries linker during maintainer builds."
   196     )
   197 ELSE()
   198   SET( CMAKE_CXX_FLAGS_MAINTAINER "-Werror -ggdb -O0" CACHE STRING
   199     "Flags used by the C++ compiler during maintainer builds."
   200     )
   201   SET( CMAKE_C_FLAGS_MAINTAINER "-Werror -O0" CACHE STRING
   202     "Flags used by the C compiler during maintainer builds."
   203     )
   204   SET( CMAKE_EXE_LINKER_FLAGS_MAINTAINER
   205     "${CMAKE_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING
   206     "Flags used for linking binaries during maintainer builds."
   207     )
   208   SET( CMAKE_SHARED_LINKER_FLAGS_MAINTAINER
   209     "${CMAKE_SHARED_LINKER_FLAGS_DEBUG}" CACHE STRING
   210     "Flags used by the shared libraries linker during maintainer builds."
   211     )
   212 ENDIF()
   213 
   214 MARK_AS_ADVANCED(
   215     CMAKE_CXX_FLAGS_MAINTAINER
   216     CMAKE_C_FLAGS_MAINTAINER
   217     CMAKE_EXE_LINKER_FLAGS_MAINTAINER
   218     CMAKE_SHARED_LINKER_FLAGS_MAINTAINER )
   219 
   220 IF(CMAKE_CONFIGURATION_TYPES)
   221   LIST(APPEND CMAKE_CONFIGURATION_TYPES Maintainer)
   222   LIST(REMOVE_DUPLICATES CMAKE_CONFIGURATION_TYPES)
   223   SET(CMAKE_CONFIGURATION_TYPES "${CMAKE_CONFIGURATION_TYPES}" CACHE STRING
   224       "Add the configurations that we need"
   225       FORCE)
   226  endif()
   227 
   228 IF(NOT CMAKE_BUILD_TYPE)
   229   SET(CMAKE_BUILD_TYPE "Release")
   230 ENDIF()
   231 
   232 SET( CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}" CACHE STRING
   233     "Choose the type of build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug Release RelWithDebInfo MinSizeRel Maintainer."
   234     FORCE )
   235 
   236 SET_DIRECTORY_PROPERTIES(PROPERTIES
   237   COMPILE_DEFINITIONS_DEBUG "LEMON_ENABLE_DEBUG"
   238   COMPILE_DEFINITIONS_MAINTAINER "LEMON_ENABLE_DEBUG"
   239 )
   240 
   241 INCLUDE(CheckTypeSize)
   242 CHECK_TYPE_SIZE("long long" LONG_LONG)
   243 SET(LEMON_HAVE_LONG_LONG ${HAVE_LONG_LONG})
   244 
   245 INCLUDE(FindThreads)
   246 
   247 IF(NOT LEMON_THREADING)
   248   IF(CMAKE_USE_PTHREADS_INIT)
   249     SET(LEMON_THREADING "Pthread")
   250   ELSEIF(CMAKE_USE_WIN32_THREADS_INIT)
   251     SET(LEMON_THREADING "Win32")
   252   ELSE()
   253     SET(LEMON_THREADING "None")
   254   ENDIF()
   255 ENDIF()
   256 
   257 SET( LEMON_THREADING "${LEMON_THREADING}" CACHE STRING
   258   "Choose the threading library, options are: Pthread Win32 None."
   259   FORCE )
   260 
   261 IF(LEMON_THREADING STREQUAL "Pthread")
   262   SET(LEMON_USE_PTHREAD TRUE)
   263 ELSEIF(LEMON_THREADING STREQUAL "Win32")
   264   SET(LEMON_USE_WIN32_THREADS TRUE)
   265 ENDIF()
   266 
   267 ENABLE_TESTING()
   268 
   269 
   270 INCLUDE(CheckCXXCompilerFlag)
   271 CHECK_CXX_COMPILER_FLAG("-std=c++11" LEMON_CXX11)
   272 IF(LEMON_CXX11)
   273   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
   274 ENDIF()
   275 
   276 
   277 IF(${CMAKE_BUILD_TYPE} STREQUAL "Maintainer")
   278   ADD_CUSTOM_TARGET(check ALL COMMAND ${CMAKE_CTEST_COMMAND})
   279 ELSE()
   280   ADD_CUSTOM_TARGET(check COMMAND ${CMAKE_CTEST_COMMAND})
   281 ENDIF()
   282 
   283 ADD_SUBDIRECTORY(lemon)
   284 IF(${CMAKE_SOURCE_DIR} STREQUAL ${PROJECT_SOURCE_DIR})
   285   ADD_SUBDIRECTORY(contrib)
   286   ADD_SUBDIRECTORY(demo)
   287   ADD_SUBDIRECTORY(tools)
   288   ADD_SUBDIRECTORY(doc)
   289   ADD_SUBDIRECTORY(test)
   290 ENDIF()
   291 
   292 CONFIGURE_FILE(
   293   ${PROJECT_SOURCE_DIR}/cmake/LEMONConfig.cmake.in
   294   ${PROJECT_BINARY_DIR}/cmake/LEMONConfig.cmake
   295   @ONLY
   296 )
   297 IF(UNIX)
   298   INSTALL(
   299     FILES ${PROJECT_BINARY_DIR}/cmake/LEMONConfig.cmake
   300     DESTINATION share/lemon/cmake
   301   )
   302 ELSEIF(WIN32)
   303   INSTALL(
   304     FILES ${PROJECT_BINARY_DIR}/cmake/LEMONConfig.cmake
   305     DESTINATION cmake
   306   )
   307 ENDIF()
   308 
   309 CONFIGURE_FILE(
   310   ${PROJECT_SOURCE_DIR}/cmake/version.cmake.in
   311   ${PROJECT_BINARY_DIR}/cmake/version.cmake
   312   @ONLY
   313 )
   314 
   315 SET(ARCHIVE_BASE_NAME ${CMAKE_PROJECT_NAME})
   316 STRING(TOLOWER ${ARCHIVE_BASE_NAME} ARCHIVE_BASE_NAME)
   317 SET(ARCHIVE_NAME ${ARCHIVE_BASE_NAME}-${PROJECT_VERSION})
   318 ADD_CUSTOM_TARGET(dist
   319   COMMAND cmake -E remove_directory ${ARCHIVE_NAME}
   320   COMMAND hg archive ${ARCHIVE_NAME}
   321   COMMAND cmake -E copy cmake/version.cmake ${ARCHIVE_NAME}/cmake/version.cmake
   322   COMMAND tar -czf ${ARCHIVE_BASE_NAME}-nodoc-${PROJECT_VERSION}.tar.gz ${ARCHIVE_NAME}
   323   COMMAND zip -r ${ARCHIVE_BASE_NAME}-nodoc-${PROJECT_VERSION}.zip ${ARCHIVE_NAME}
   324   COMMAND cmake -E copy_directory doc/html ${ARCHIVE_NAME}/doc/html
   325   COMMAND tar -czf ${ARCHIVE_NAME}.tar.gz ${ARCHIVE_NAME}
   326   COMMAND zip -r ${ARCHIVE_NAME}.zip ${ARCHIVE_NAME}
   327   COMMAND cmake -E copy_directory doc/html ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}
   328   COMMAND tar -czf ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}.tar.gz ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}
   329   COMMAND zip -r ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}.zip ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}
   330   COMMAND cmake -E remove_directory ${ARCHIVE_NAME}
   331   COMMAND cmake -E remove_directory ${ARCHIVE_BASE_NAME}-doc-${PROJECT_VERSION}
   332   DEPENDS html
   333   WORKING_DIRECTORY ${PROJECT_BINARY_DIR})
   334 
   335 # CPACK config (Basically for NSIS)
   336 IF(${CMAKE_SOURCE_DIR} STREQUAL ${PROJECT_SOURCE_DIR})
   337   SET(CPACK_PACKAGE_NAME ${PROJECT_NAME})
   338   SET(CPACK_PACKAGE_VENDOR "EGRES")
   339   SET(CPACK_PACKAGE_DESCRIPTION_SUMMARY
   340     "LEMON - Library for Efficient Modeling and Optimization in Networks")
   341   SET(CPACK_RESOURCE_FILE_LICENSE "${PROJECT_SOURCE_DIR}/LICENSE")
   342 
   343   SET(CPACK_PACKAGE_VERSION ${PROJECT_VERSION})
   344 
   345   SET(CPACK_PACKAGE_INSTALL_DIRECTORY
   346     "${PROJECT_NAME} ${PROJECT_VERSION}")
   347   SET(CPACK_PACKAGE_INSTALL_REGISTRY_KEY
   348     "${PROJECT_NAME} ${PROJECT_VERSION}")
   349 
   350   SET(CPACK_COMPONENTS_ALL headers library html_documentation bin)
   351 
   352   SET(CPACK_COMPONENT_HEADERS_DISPLAY_NAME "C++ headers")
   353   SET(CPACK_COMPONENT_LIBRARY_DISPLAY_NAME "Dynamic-link library")
   354   SET(CPACK_COMPONENT_BIN_DISPLAY_NAME "Command line utilities")
   355   SET(CPACK_COMPONENT_HTML_DOCUMENTATION_DISPLAY_NAME "HTML documentation")
   356 
   357   SET(CPACK_COMPONENT_HEADERS_DESCRIPTION
   358     "C++ header files")
   359   SET(CPACK_COMPONENT_LIBRARY_DESCRIPTION
   360     "DLL and import library")
   361   SET(CPACK_COMPONENT_BIN_DESCRIPTION
   362     "Command line utilities")
   363   SET(CPACK_COMPONENT_HTML_DOCUMENTATION_DESCRIPTION
   364     "Doxygen generated documentation")
   365 
   366   SET(CPACK_COMPONENT_HEADERS_DEPENDS library)
   367 
   368   SET(CPACK_COMPONENT_HEADERS_GROUP "Development")
   369   SET(CPACK_COMPONENT_LIBRARY_GROUP "Development")
   370   SET(CPACK_COMPONENT_HTML_DOCUMENTATION_GROUP "Documentation")
   371 
   372   SET(CPACK_COMPONENT_GROUP_DEVELOPMENT_DESCRIPTION
   373     "Components needed to develop software using LEMON")
   374   SET(CPACK_COMPONENT_GROUP_DOCUMENTATION_DESCRIPTION
   375     "Documentation of LEMON")
   376 
   377   SET(CPACK_ALL_INSTALL_TYPES Full Developer)
   378 
   379   SET(CPACK_COMPONENT_HEADERS_INSTALL_TYPES Developer Full)
   380   SET(CPACK_COMPONENT_LIBRARY_INSTALL_TYPES Developer Full)
   381   SET(CPACK_COMPONENT_HTML_DOCUMENTATION_INSTALL_TYPES Full)
   382 
   383   SET(CPACK_GENERATOR "NSIS")
   384   SET(CPACK_NSIS_MUI_ICON "${PROJECT_SOURCE_DIR}/cmake/nsis/lemon.ico")
   385   SET(CPACK_NSIS_MUI_UNIICON "${PROJECT_SOURCE_DIR}/cmake/nsis/uninstall.ico")
   386   #SET(CPACK_PACKAGE_ICON "${PROJECT_SOURCE_DIR}/cmake/nsis\\\\installer.bmp")
   387   SET(CPACK_NSIS_INSTALLED_ICON_NAME "bin\\\\lemon.ico")
   388   SET(CPACK_NSIS_DISPLAY_NAME "${CPACK_PACKAGE_INSTALL_DIRECTORY} ${PROJECT_NAME}")
   389   SET(CPACK_NSIS_HELP_LINK "http:\\\\\\\\lemon.cs.elte.hu")
   390   SET(CPACK_NSIS_URL_INFO_ABOUT "http:\\\\\\\\lemon.cs.elte.hu")
   391   SET(CPACK_NSIS_CONTACT "lemon-user@lemon.cs.elte.hu")
   392   SET(CPACK_NSIS_CREATE_ICONS_EXTRA "
   393     CreateShortCut \\\"$SMPROGRAMS\\\\$STARTMENU_FOLDER\\\\Documentation.lnk\\\" \\\"$INSTDIR\\\\share\\\\doc\\\\index.html\\\"
   394     ")
   395   SET(CPACK_NSIS_DELETE_ICONS_EXTRA "
   396     !insertmacro MUI_STARTMENU_GETFOLDER Application $MUI_TEMP
   397     Delete \\\"$SMPROGRAMS\\\\$MUI_TEMP\\\\Documentation.lnk\\\"
   398     ")
   399 
   400   INCLUDE(CPack)
   401 ENDIF()