# Ceres Solver - A fast non-linear least squares minimizer

# Copyright 2015 Google Inc. All rights reserved.

# http://ceres-solver.org/

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions are met:

#

# * Redistributions of source code must retain the above copyright notice,

#   this list of conditions and the following disclaimer.

# * Redistributions in binary form must reproduce the above copyright notice,

#   this list of conditions and the following disclaimer in the documentation

#   and/or other materials provided with the distribution.

# * Neither the name of Google Inc. nor the names of its contributors may be

#   used to endorse or promote products derived from this software without

#   specific prior written permission.

#

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

# POSSIBILITY OF SUCH DAMAGE.

#

# Author: alexs.mac@gmail.com (Alex Stewart)

#

# FindEigen.cmake - Find Eigen library, version >= 3.

#

# This module defines the following variables:

#

# EIGEN_FOUND: TRUE iff Eigen is found.

# EIGEN_INCLUDE_DIRS: Include directories for Eigen.

# EIGEN_VERSION: Extracted from Eigen/src/Core/util/Macros.h

# EIGEN_WORLD_VERSION: Equal to 3 if EIGEN_VERSION = 3.2.0

# EIGEN_MAJOR_VERSION: Equal to 2 if EIGEN_VERSION = 3.2.0

# EIGEN_MINOR_VERSION: Equal to 0 if EIGEN_VERSION = 3.2.0

# FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION: True iff the version of Eigen

#                                            found was built & installed /

#                                            exported as a CMake package.

#

# The following variables control the behaviour of this module:

#

# EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION: TRUE/FALSE, iff TRUE then

#                           then prefer using an exported CMake configuration

#                           generated by Eigen over searching for the

#                           Eigen components manually.  Otherwise (FALSE)

#                           ignore any exported Eigen CMake configurations and

#                           always perform a manual search for the components.

#                           Default: TRUE iff user does not define this variable

#                           before we are called, and does NOT specify

#                           EIGEN_INCLUDE_DIR_HINTS, otherwise FALSE.

# EIGEN_INCLUDE_DIR_HINTS: List of additional directories in which to

#                          search for eigen includes, e.g: /timbuktu/eigen3.

#

# The following variables are also defined by this module, but in line with

# CMake recommended FindPackage() module style should NOT be referenced directly

# by callers (use the plural variables detailed above instead).  These variables

# do however affect the behaviour of the module via FIND_[PATH/LIBRARY]() which

# are NOT re-called (i.e. search for library is not repeated) if these variables

# are set with valid values _in the CMake cache_. This means that if these

# variables are set directly in the cache, either by the user in the CMake GUI,

# or by the user passing -DVAR=VALUE directives to CMake when called (which

# explicitly defines a cache variable), then they will be used verbatim,

# bypassing the HINTS variables and other hard-coded search locations.

#

# EIGEN_INCLUDE_DIR: Include directory for CXSparse, not including the

#                    include directory of any dependencies.

# Called if we failed to find Eigen or any of it's required dependencies,

# unsets all public (designed to be used externally) variables and reports

# error message at priority depending upon [REQUIRED/QUIET/<NONE>] argument.

macro(EIGEN_REPORT_NOT_FOUND REASON_MSG)

  unset(EIGEN_FOUND)

  unset(EIGEN_INCLUDE_DIRS)

  unset(FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION)

  # Make results of search visible in the CMake GUI if Eigen has not

  # been found so that user does not have to toggle to advanced view.

  mark_as_advanced(CLEAR EIGEN_INCLUDE_DIR)

  # Note <package>_FIND_[REQUIRED/QUIETLY] variables defined by FindPackage()

  # use the camelcase library name, not uppercase.

  if (Eigen_FIND_QUIETLY)

    message(STATUS "Failed to find Eigen - " ${REASON_MSG} ${ARGN})

  elseif (Eigen_FIND_REQUIRED)

    message(FATAL_ERROR "Failed to find Eigen - " ${REASON_MSG} ${ARGN})

  else()

    # Neither QUIETLY nor REQUIRED, use no priority which emits a message

    # but continues configuration and allows generation.

    message("-- Failed to find Eigen - " ${REASON_MSG} ${ARGN})

  endif ()

  return()

endmacro(EIGEN_REPORT_NOT_FOUND)

# Protect against any alternative find_package scripts for this library having

# been called previously (in a client project) which set EIGEN_FOUND, but not

# the other variables we require / set here which could cause the search logic

# here to fail.

unset(EIGEN_FOUND)

# -----------------------------------------------------------------

# By default, if the user has expressed no preference for using an exported

# Eigen CMake configuration over performing a search for the installed

# components, and has not specified any hints for the search locations, then

# prefer an exported configuration if available.

if (NOT DEFINED EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION

    AND NOT EIGEN_INCLUDE_DIR_HINTS)

  message(STATUS "No preference for use of exported Eigen CMake configuration "

    "set, and no hints for include directory provided. "

    "Defaulting to preferring an installed/exported Eigen CMake configuration "

    "if available.")

  set(EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION TRUE)

endif()

if (EIGEN_PREFER_EXPORTED_EIGEN_CMAKE_CONFIGURATION)

  # Try to find an exported CMake configuration for Eigen.

  #

  # We search twice, s/t we can invert the ordering of precedence used by

  # find_package() for exported package build directories, and installed

  # packages (found via CMAKE_SYSTEM_PREFIX_PATH), listed as items 6) and 7)

  # respectively in [1].

  #

  # By default, exported build directories are (in theory) detected first, and

  # this is usually the case on Windows.  However, on OS X & Linux, the install

  # path (/usr/local) is typically present in the PATH environment variable

  # which is checked in item 4) in [1] (i.e. before both of the above, unless

  # NO_SYSTEM_ENVIRONMENT_PATH is passed).  As such on those OSs installed

  # packages are usually detected in preference to exported package build

  # directories.

  #

  # To ensure a more consistent response across all OSs, and as users usually

  # want to prefer an installed version of a package over a locally built one

  # where both exist (esp. as the exported build directory might be removed

  # after installation), we first search with NO_CMAKE_PACKAGE_REGISTRY which

  # means any build directories exported by the user are ignored, and thus

  # installed directories are preferred.  If this fails to find the package

  # we then research again, but without NO_CMAKE_PACKAGE_REGISTRY, so any

  # exported build directories will now be detected.

  #

  # To prevent confusion on Windows, we also pass NO_CMAKE_BUILDS_PATH (which

  # is item 5) in [1]), to not preferentially use projects that were built

  # recently with the CMake GUI to ensure that we always prefer an installed

  # version if available.

  #

  # [1] http://www.cmake.org/cmake/help/v2.8.11/cmake.html#command:find_package

  find_package(Eigen3 QUIET

                      NO_MODULE

                      NO_CMAKE_PACKAGE_REGISTRY

                      NO_CMAKE_BUILDS_PATH)

  if (EIGEN3_FOUND)

    message(STATUS "Found installed version of Eigen: ${Eigen3_DIR}")

  else()

    # Failed to find an installed version of Eigen, repeat search allowing

    # exported build directories.

    message(STATUS "Failed to find installed Eigen CMake configuration, "

      "searching for Eigen build directories exported with CMake.")

    # Again pass NO_CMAKE_BUILDS_PATH, as we know that Eigen is exported and

    # do not want to treat projects built with the CMake GUI preferentially.

    find_package(Eigen3 QUIET

                        NO_MODULE

                        NO_CMAKE_BUILDS_PATH)

    if (EIGEN3_FOUND)

      message(STATUS "Found exported Eigen build directory: ${Eigen3_DIR}")

    endif()

  endif()

  if (EIGEN3_FOUND)

    set(FOUND_INSTALLED_EIGEN_CMAKE_CONFIGURATION TRUE)

    set(EIGEN_FOUND ${EIGEN3_FOUND})

    set(EIGEN_INCLUDE_DIR "${EIGEN3_INCLUDE_DIR}" CACHE STRING

      "Eigen include directory" FORCE)

  else()

    message(STATUS "Failed to find an installed/exported CMake configuration "

      "for Eigen, will perform search for installed Eigen components.")

  endif()

endif()

if (NOT EIGEN_FOUND)

  # Search user-installed locations first, so that we prefer user installs

  # to system installs where both exist.

  list(APPEND EIGEN_CHECK_INCLUDE_DIRS

    /usr/local/include

    /usr/local/homebrew/include # Mac OS X

    /opt/local/var/macports/software # Mac OS X.

    /opt/local/include

    /usr/include)

  # Additional suffixes to try appending to each search path.

  list(APPEND EIGEN_CHECK_PATH_SUFFIXES

    eigen3 # Default root directory for Eigen.

    Eigen/include/eigen3 # Windows (for C:/Program Files prefix) < 3.3

    Eigen3/include/eigen3 ) # Windows (for C:/Program Files prefix) >= 3.3

  # Search supplied hint directories first if supplied.

  find_path(EIGEN_INCLUDE_DIR

    NAMES Eigen/Core

    HINTS ${EIGEN_INCLUDE_DIR_HINTS}

    PATHS ${EIGEN_CHECK_INCLUDE_DIRS}

    PATH_SUFFIXES ${EIGEN_CHECK_PATH_SUFFIXES})

  if (NOT EIGEN_INCLUDE_DIR OR

      NOT EXISTS ${EIGEN_INCLUDE_DIR})

    eigen_report_not_found(

      "Could not find eigen3 include directory, set EIGEN_INCLUDE_DIR to "

      "path to eigen3 include directory, e.g. /usr/local/include/eigen3.")

  endif (NOT EIGEN_INCLUDE_DIR OR

    NOT EXISTS ${EIGEN_INCLUDE_DIR})

  # Mark internally as found, then verify. EIGEN_REPORT_NOT_FOUND() unsets

  # if called.

  set(EIGEN_FOUND TRUE)

endif()

# Extract Eigen version from Eigen/src/Core/util/Macros.h

if (EIGEN_INCLUDE_DIR)

  set(EIGEN_VERSION_FILE ${EIGEN_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h)

  if (NOT EXISTS ${EIGEN_VERSION_FILE})

    eigen_report_not_found(

      "Could not find file: ${EIGEN_VERSION_FILE} "

      "containing version information in Eigen install located at: "

      "${EIGEN_INCLUDE_DIR}.")

  else (NOT EXISTS ${EIGEN_VERSION_FILE})

    file(READ ${EIGEN_VERSION_FILE} EIGEN_VERSION_FILE_CONTENTS)

    string(REGEX MATCH "#define EIGEN_WORLD_VERSION [0-9]+"

      EIGEN_WORLD_VERSION "${EIGEN_VERSION_FILE_CONTENTS}")

    string(REGEX REPLACE "#define EIGEN_WORLD_VERSION ([0-9]+)" "\\1"

      EIGEN_WORLD_VERSION "${EIGEN_WORLD_VERSION}")

    string(REGEX MATCH "#define EIGEN_MAJOR_VERSION [0-9]+"

      EIGEN_MAJOR_VERSION "${EIGEN_VERSION_FILE_CONTENTS}")

    string(REGEX REPLACE "#define EIGEN_MAJOR_VERSION ([0-9]+)" "\\1"

      EIGEN_MAJOR_VERSION "${EIGEN_MAJOR_VERSION}")

    string(REGEX MATCH "#define EIGEN_MINOR_VERSION [0-9]+"

      EIGEN_MINOR_VERSION "${EIGEN_VERSION_FILE_CONTENTS}")

    string(REGEX REPLACE "#define EIGEN_MINOR_VERSION ([0-9]+)" "\\1"

      EIGEN_MINOR_VERSION "${EIGEN_MINOR_VERSION}")

    # This is on a single line s/t CMake does not interpret it as a list of

    # elements and insert ';' separators which would result in 3.;2.;0 nonsense.

    set(EIGEN_VERSION "${EIGEN_WORLD_VERSION}.${EIGEN_MAJOR_VERSION}.${EIGEN_MINOR_VERSION}")

  endif (NOT EXISTS ${EIGEN_VERSION_FILE})

endif (EIGEN_INCLUDE_DIR)

# Set standard CMake FindPackage variables if found.

if (EIGEN_FOUND)

  set(EIGEN_INCLUDE_DIRS ${EIGEN_INCLUDE_DIR})

endif (EIGEN_FOUND)

# Handle REQUIRED / QUIET optional arguments and version.

include(FindPackageHandleStandardArgs)

find_package_handle_standard_args(Eigen

  REQUIRED_VARS EIGEN_INCLUDE_DIRS

  VERSION_VAR EIGEN_VERSION)

# Only mark internal variables as advanced if we found Eigen, otherwise

# leave it visible in the standard GUI for the user to set manually.

if (EIGEN_FOUND)

  mark_as_advanced(FORCE EIGEN_INCLUDE_DIR

    Eigen3_DIR) # Autogenerated by find_package(Eigen3)

endif (EIGEN_FOUND)