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feat(3rdparty): add eigen and ceres
2019-01-03 10:25:18 +02:00
.. _chapter-building:
=======================
Building & Installation
=======================
Getting the source code
=======================
.. _section-source:
You can start with the `latest stable release
<http://ceres-solver.org/ceres-solver-1.11.0.tar.gz>`_ . Or if you want
the latest version, you can clone the git repository
.. code-block:: bash
git clone https://ceres-solver.googlesource.com/ceres-solver
.. _section-dependencies:
Dependencies
============
Ceres relies on a number of open source libraries, some of which are
optional. For details on customizing the build process, see
:ref:`section-customizing` .
- `Eigen <http://eigen.tuxfamily.org/index.php?title=Main_Page>`_
3.2.2 or later **strongly** recommended, 3.1.0 or later **required**.
.. NOTE ::
Ceres can also use Eigen as a sparse linear algebra
library. Please see the documentation for ``EIGENSPARSE`` for
more details.
- `CMake <http://www.cmake.org>`_ 2.8.0 or later.
**Required on all platforms except for Android.**
- `Google Log <http://code.google.com/p/google-glog>`_ 0.3.1 or
later. **Recommended**
.. NOTE::
Ceres has a minimal replacement of ``glog`` called ``miniglog``
that can be enabled with the ``MINIGLOG`` build
option. ``miniglog`` is needed on Android as ``glog`` currently
does not build using the NDK. It can however be used on other
platforms too.
**We do not advise using** ``miniglog`` **on platforms other than
Android due to the various performance and functionality
compromises in** ``miniglog``.
.. NOTE ::
If you are compiling ``glog`` from source, please note that currently,
the unit tests for ``glog`` (which are enabled by default) do not compile
against a default build of ``gflags`` 2.1 as the gflags namespace changed
from ``google::`` to ``gflags::``. A patch to fix this is available from
`here <https://code.google.com/p/google-glog/issues/detail?id=194>`_.
- `Google Flags <http://code.google.com/p/gflags>`_. Needed to build
examples and tests.
- `SuiteSparse
<http://faculty.cse.tamu.edu/davis/suitesparse.html>`_. Needed for
solving large sparse linear systems. **Optional; strongly recomended
for large scale bundle adjustment**
- `CXSparse <http://faculty.cse.tamu.edu/davis/suitesparse.html>`_.
Similar to ``SuiteSparse`` but simpler and slower. CXSparse has
no dependencies on ``LAPACK`` and ``BLAS``. This makes for a simpler
build process and a smaller binary. **Optional**
- `BLAS <http://www.netlib.org/blas/>`_ and `LAPACK
<http://www.netlib.org/lapack/>`_ routines are needed by
``SuiteSparse``, and optionally used by Ceres directly for some
operations.
On ``UNIX`` OSes other than Mac OS X we recommend `ATLAS
<http://math-atlas.sourceforge.net/>`_, which includes ``BLAS`` and
``LAPACK`` routines. It is also possible to use `OpenBLAS
<https://github.com/xianyi/OpenBLAS>`_ . However, one needs to be
careful to `turn off the threading
<https://github.com/xianyi/OpenBLAS/wiki/faq#wiki-multi-threaded>`_
inside ``OpenBLAS`` as it conflicts with use of threads in Ceres.
Mac OS X ships with an optimized ``LAPACK`` and ``BLAS``
implementation as part of the ``Accelerate`` framework. The Ceres
build system will automatically detect and use it.
For Windows things are much more complicated. `LAPACK For
Windows <http://icl.cs.utk.edu/lapack-for-windows/lapack/>`_
has detailed instructions..
**Optional but required for** ``SuiteSparse``.
.. _section-linux:
Linux
=====
We will use `Ubuntu <http://www.ubuntu.com>`_ as our example linux
distribution.
.. NOTE::
Up to at least Ubuntu 14.04, the SuiteSparse package in the official
package repository (built from SuiteSparse v3.4.0) **cannot** be used
to build Ceres as a *shared* library. Thus if you want to build
Ceres as a shared library using SuiteSparse, you must perform a
source install of SuiteSparse or use an external PPA (see
`bug report here <https://bugs.launchpad.net/ubuntu/+source/suitesparse/+bug/1333214>`_).
It is recommended that you use the current version of SuiteSparse
(4.2.1 at the time of writing).
Start by installing all the dependencies.
.. code-block:: bash
# CMake
sudo apt-get install cmake
# google-glog + gflags
sudo apt-get install libgoogle-glog-dev
# BLAS & LAPACK
sudo apt-get install libatlas-base-dev
# Eigen3
sudo apt-get install libeigen3-dev
# SuiteSparse and CXSparse (optional)
# - If you want to build Ceres as a *static* library (the default)
# you can use the SuiteSparse package in the main Ubuntu package
# repository:
sudo apt-get install libsuitesparse-dev
# - However, if you want to build Ceres as a *shared* library, you must
# add the following PPA:
sudo add-apt-repository ppa:bzindovic/suitesparse-bugfix-1319687
sudo apt-get update
sudo apt-get install libsuitesparse-dev
We are now ready to build, test, and install Ceres.
.. code-block:: bash
tar zxf ceres-solver-1.11.0.tar.gz
mkdir ceres-bin
cd ceres-bin
cmake ../ceres-solver-1.11.0
make -j3
make test
# Optionally install Ceres, it can also be exported using CMake which
# allows Ceres to be used without requiring installation, see the documentation
# for the EXPORT_BUILD_DIR option for more information.
make install
You can also try running the command line bundling application with one of the
included problems, which comes from the University of Washington's BAL
dataset [Agarwal]_.
.. code-block:: bash
bin/simple_bundle_adjuster ../ceres-solver-1.11.0/data/problem-16-22106-pre.txt
This runs Ceres for a maximum of 10 iterations using the
``DENSE_SCHUR`` linear solver. The output should look something like
this.
.. code-block:: bash
iter cost cost_change |gradient| |step| tr_ratio tr_radius ls_iter iter_time total_time
0 4.185660e+06 0.00e+00 1.09e+08 0.00e+00 0.00e+00 1.00e+04 0 7.59e-02 3.37e-01
1 1.062590e+05 4.08e+06 8.99e+06 5.36e+02 9.82e-01 3.00e+04 1 1.65e-01 5.03e-01
2 4.992817e+04 5.63e+04 8.32e+06 3.19e+02 6.52e-01 3.09e+04 1 1.45e-01 6.48e-01
3 1.899774e+04 3.09e+04 1.60e+06 1.24e+02 9.77e-01 9.26e+04 1 1.43e-01 7.92e-01
4 1.808729e+04 9.10e+02 3.97e+05 6.39e+01 9.51e-01 2.78e+05 1 1.45e-01 9.36e-01
5 1.803399e+04 5.33e+01 1.48e+04 1.23e+01 9.99e-01 8.33e+05 1 1.45e-01 1.08e+00
6 1.803390e+04 9.02e-02 6.35e+01 8.00e-01 1.00e+00 2.50e+06 1 1.50e-01 1.23e+00
Ceres Solver v1.11.0 Solve Report
----------------------------------
Original Reduced
Parameter blocks 22122 22122
Parameters 66462 66462
Residual blocks 83718 83718
Residual 167436 167436
Minimizer TRUST_REGION
Dense linear algebra library EIGEN
Trust region strategy LEVENBERG_MARQUARDT
Given Used
Linear solver DENSE_SCHUR DENSE_SCHUR
Threads 1 1
Linear solver threads 1 1
Linear solver ordering AUTOMATIC 22106, 16
Cost:
Initial 4.185660e+06
Final 1.803390e+04
Change 4.167626e+06
Minimizer iterations 6
Successful steps 6
Unsuccessful steps 0
Time (in seconds):
Preprocessor 0.261
Residual evaluation 0.082
Jacobian evaluation 0.412
Linear solver 0.442
Minimizer 1.051
Postprocessor 0.002
Total 1.357
Termination: CONVERGENCE (Function tolerance reached. |cost_change|/cost: 1.769766e-09 <= 1.000000e-06)
.. section-osx:
Mac OS X
========
.. NOTE::
Ceres will not compile using Xcode 4.5.x (Clang version 4.1) due to a
bug in that version of Clang. If you are running Xcode 4.5.x, please
update to Xcode >= 4.6.x before attempting to build Ceres.
On OS X, you can either use `MacPorts <https://www.macports.org/>`_ or
`Homebrew <http://mxcl.github.com/homebrew/>`_ to install Ceres Solver.
If using `MacPorts <https://www.macports.org/>`_, then
.. code-block:: bash
sudo port install ceres-solver
will install the latest version.
If using `Homebrew <http://mxcl.github.com/homebrew/>`_ and assuming
that you have the ``homebrew/science`` [#f1]_ tap enabled, then
.. code-block:: bash
brew install ceres-solver
will install the latest stable version along with all the required
dependencies and
.. code-block:: bash
brew install ceres-solver --HEAD
will install the latest version in the git repo.
You can also install each of the dependencies by hand using `Homebrew
<http://mxcl.github.com/homebrew/>`_. There is no need to install
``BLAS`` or ``LAPACK`` separately as OS X ships with optimized
``BLAS`` and ``LAPACK`` routines as part of the `vecLib
<https://developer.apple.com/library/mac/#documentation/Performance/Conceptual/vecLib/Reference/reference.html>`_
framework.
.. code-block:: bash
# CMake
brew install cmake
# google-glog and gflags
brew install glog
# Eigen3
brew install eigen
# SuiteSparse and CXSparse
brew install suite-sparse
We are now ready to build, test, and install Ceres.
.. code-block:: bash
tar zxf ceres-solver-1.11.0.tar.gz
mkdir ceres-bin
cd ceres-bin
cmake ../ceres-solver-1.11.0
make -j3
make test
# Optionally install Ceres, it can also be exported using CMake which
# allows Ceres to be used without requiring installation, see the
# documentation for the EXPORT_BUILD_DIR option for more information.
make install
Like the Linux build, you should now be able to run
``bin/simple_bundle_adjuster``.
.. rubric:: Footnotes
.. [#f1] Ceres and many of its dependencies are in `homebrew/science
<https://github.com/Homebrew/homebrew-science>`_ tap. So, if you
don't have this tap enabled, then you will need to enable it as
follows before executing any of the commands in this section.
.. code-block:: bash
brew tap homebrew/science
.. _section-windows:
Windows
=======
.. NOTE::
If you find the following CMake difficult to set up, then you may
be interested in a `Microsoft Visual Studio wrapper
<https://github.com/tbennun/ceres-windows>`_ for Ceres Solver by Tal
Ben-Nun.
On Windows, we support building with Visual Studio 2010 or newer. Note
that the Windows port is less featureful and less tested than the
Linux or Mac OS X versions due to the lack of an officially supported
way of building SuiteSparse and CXSparse. There are however a number
of unofficial ways of building these libraries. Building on Windows
also a bit more involved since there is no automated way to install
dependencies.
.. NOTE:: Using ``google-glog`` & ``miniglog`` with windows.h.
The windows.h header if used with GDI (Graphics Device Interface)
defines ``ERROR``, which conflicts with the definition of ``ERROR``
as a LogSeverity level in ``google-glog`` and ``miniglog``. There
are at least two possible fixes to this problem:
#. Use ``google-glog`` and define ``GLOG_NO_ABBREVIATED_SEVERITIES``
when building Ceres and your own project, as documented
`here <http://google-glog.googlecode.com/svn/trunk/doc/glog.html>`__.
Note that this fix will not work for ``miniglog``,
but use of ``miniglog`` is strongly discouraged on any platform for which
``google-glog`` is available (which includes Windows).
#. If you do not require GDI, then define ``NOGDI`` **before** including
windows.h. This solution should work for both ``google-glog`` and
``miniglog`` and is documented for ``google-glog``
`here <https://code.google.com/p/google-glog/issues/detail?id=33>`__.
#. Make a toplevel directory for deps & build & src somewhere: ``ceres/``
#. Get dependencies; unpack them as subdirectories in ``ceres/``
(``ceres/eigen``, ``ceres/glog``, etc)
#. ``Eigen`` 3.1 (needed on Windows; 3.0.x will not work). There is
no need to build anything; just unpack the source tarball.
#. ``google-glog`` Open up the Visual Studio solution and build it.
#. ``gflags`` Open up the Visual Studio solution and build it.
#. (Experimental) ``SuiteSparse`` Previously SuiteSparse was not available
on Windows, recently it has become possible to build it on Windows using
the `suitesparse-metis-for-windows <https://github.com/jlblancoc/suitesparse-metis-for-windows>`_
project. If you wish to use ``SuiteSparse``, follow their instructions
for obtaining and building it.
#. (Experimental) ``CXSparse`` Previously CXSparse was not available on
Windows, there are now several ports that enable it to be, including:
`[1] <https://github.com/PetterS/CXSparse>`_ and
`[2] <https://github.com/TheFrenchLeaf/CXSparse>`_. If you wish to use
``CXSparse``, follow their instructions for obtaining and building it.
#. Unpack the Ceres tarball into ``ceres``. For the tarball, you
should get a directory inside ``ceres`` similar to
``ceres-solver-1.3.0``. Alternately, checkout Ceres via ``git`` to
get ``ceres-solver.git`` inside ``ceres``.
#. Install ``CMake``,
#. Make a dir ``ceres/ceres-bin`` (for an out-of-tree build)
#. Run ``CMake``; select the ``ceres-solver-X.Y.Z`` or
``ceres-solver.git`` directory for the CMake file. Then select the
``ceres-bin`` for the build dir.
#. Try running ``Configure``. It won't work. It'll show a bunch of options.
You'll need to set:
#. ``EIGEN_INCLUDE_DIR_HINTS``
#. ``GLOG_INCLUDE_DIR_HINTS``
#. ``GLOG_LIBRARY_DIR_HINTS``
#. ``GFLAGS_INCLUDE_DIR_HINTS``
#. ``GFLAGS_LIBRARY_DIR_HINTS``
#. (Optional) ``SUITESPARSE_INCLUDE_DIR_HINTS``
#. (Optional) ``SUITESPARSE_LIBRARY_DIR_HINTS``
#. (Optional) ``CXSPARSE_INCLUDE_DIR_HINTS``
#. (Optional) ``CXSPARSE_LIBRARY_DIR_HINTS``
to the appropriate directories where you unpacked/built them. If any of
the variables are not visible in the ``CMake`` GUI, create a new entry
for them. We recommend using the ``<NAME>_(INCLUDE/LIBRARY)_DIR_HINTS``
variables rather than setting the ``<NAME>_INCLUDE_DIR`` &
``<NAME>_LIBRARY`` variables directly to keep all of the validity
checking, and to avoid having to specify the library files manually.
#. You may have to tweak some more settings to generate a MSVC
project. After each adjustment, try pressing Configure & Generate
until it generates successfully.
#. Open the solution and build it in MSVC
To run the tests, select the ``RUN_TESTS`` target and hit **Build
RUN_TESTS** from the build menu.
Like the Linux build, you should now be able to run
``bin/simple_bundle_adjuster``.
Notes:
#. The default build is Debug; consider switching it to release mode.
#. Currently ``system_test`` is not working properly.
#. CMake puts the resulting test binaries in ``ceres-bin/examples/Debug``
by default.
#. The solvers supported on Windows are ``DENSE_QR``, ``DENSE_SCHUR``,
``CGNR``, and ``ITERATIVE_SCHUR``.
#. We're looking for someone to work with upstream ``SuiteSparse`` to
port their build system to something sane like ``CMake``, and get a
fully supported Windows port.
.. _section-android:
Android
=======
Download the ``Android NDK`` version ``r9d`` or later. Run
``ndk-build`` from inside the ``jni`` directory. Use the
``libceres.a`` that gets created.
.. _section-ios:
iOS
===
.. NOTE::
You need iOS version 7.0 or higher to build Ceres Solver.
To build Ceres for iOS, we need to force ``CMake`` to find the toolchains from
the iOS SDK instead of using the standard ones. For example:
.. code-block:: bash
cmake \
-DCMAKE_TOOLCHAIN_FILE=../ceres-solver/cmake/iOS.cmake \
-DEIGEN_INCLUDE_DIR=/path/to/eigen/header \
-DIOS_PLATFORM=<PLATFORM> \
<PATH_TO_CERES_SOURCE>
``PLATFORM`` can be: ``OS``, ``SIMULATOR`` or ``SIMULATOR64``. You can
build for ``OS`` (``armv7``, ``armv7s``, ``arm64``), ``SIMULATOR`` (``i386``) or
``SIMULATOR64`` (``x86_64``) separately and use ``lipo`` to merge them into
one static library. See ``cmake/iOS.cmake`` for more options.
After building, you will get a ``libceres.a`` library, which you will need to
add to your Xcode project.
The default CMake configuration builds a bare bones version of Ceres
Solver that only depends on Eigen (``MINIGLOG`` is compiled into Ceres if it is
used), this should be sufficient for solving small to moderate sized problems
(No ``SPARSE_SCHUR``, ``SPARSE_NORMAL_CHOLESKY`` linear solvers and no
``CLUSTER_JACOBI`` and ``CLUSTER_TRIDIAGONAL`` preconditioners).
If you decide to use ``LAPACK`` and ``BLAS``, then you also need to add
``Accelerate.framework`` to your Xcode project's linking dependency.
.. _section-customizing:
Customizing the build
=====================
It is possible to reduce the libraries needed to build Ceres and
customize the build process by setting the appropriate options in
``CMake``. These options can either be set in the ``CMake`` GUI,
or via ``-D<OPTION>=<ON/OFF>`` when running ``CMake`` from the
command line. In general, you should only modify these options from
their defaults if you know what you are doing.
.. NOTE::
If you are setting variables via ``-D<VARIABLE>=<VALUE>`` when calling
``CMake``, it is important to understand that this forcibly **overwrites** the
variable ``<VARIABLE>`` in the ``CMake`` cache at the start of *every configure*.
This can lead to confusion if you are invoking the ``CMake``
`curses <http://www.gnu.org/software/ncurses/ncurses.html>`_ terminal GUI
(via ``ccmake``, e.g. ```ccmake -D<VARIABLE>=<VALUE> <PATH_TO_SRC>``).
In this case, even if you change the value of ``<VARIABLE>`` in the ``CMake``
GUI, your changes will be **overwritten** with the value passed via
``-D<VARIABLE>=<VALUE>`` (if one exists) at the start of each configure.
As such, it is generally easier not to pass values to ``CMake`` via ``-D``
and instead interactively experiment with their values in the ``CMake`` GUI.
If they are not present in the *Standard View*, toggle to the *Advanced View*
with ``<t>``.
Options controlling Ceres configuration
---------------------------------------
#. ``LAPACK [Default: ON]``: By default Ceres will use ``LAPACK`` (&
``BLAS``) if they are found. Turn this ``OFF`` to build Ceres
without ``LAPACK``. Turning this ``OFF`` also disables
``SUITESPARSE`` as it depends on ``LAPACK``.
#. ``SUITESPARSE [Default: ON]``: By default, Ceres will link to
``SuiteSparse`` if it and all of its dependencies are present. Turn
this ``OFF`` to build Ceres without ``SuiteSparse``. Note that
``LAPACK`` must be ``ON`` in order to build with ``SuiteSparse``.
#. ``CXSPARSE [Default: ON]``: By default, Ceres will link to
``CXSparse`` if all its dependencies are present. Turn this ``OFF``
to build Ceres without ``CXSparse``.
#. ``EIGENSPARSE [Default: OFF]``: By default, Ceres will not use
Eigen's sparse Cholesky factorization. The is because this part of
the code is licensed under the ``LGPL`` and since ``Eigen`` is a
header only library, including this code will result in an ``LGPL``
licensed version of Ceres.
.. NOTE::
For good performance, use Eigen version 3.2.2 or later.
#. ``GFLAGS [Default: ON]``: Turn this ``OFF`` to build Ceres without
``gflags``. This will also prevent some of the example code from
building.
#. ``MINIGLOG [Default: OFF]``: Ceres includes a stripped-down,
minimal implementation of ``glog`` which can optionally be used as
a substitute for ``glog``, thus removing ``glog`` as a required
dependency. Turn this ``ON`` to use this minimal ``glog``
implementation.
#. ``SCHUR_SPECIALIZATIONS [Default: ON]``: If you are concerned about
binary size/compilation time over some small (10-20%) performance
gains in the ``SPARSE_SCHUR`` solver, you can disable some of the
template specializations by turning this ``OFF``.
#. ``OPENMP [Default: ON]``: On certain platforms like Android,
multi-threading with ``OpenMP`` is not supported. Turn this ``OFF``
to disable multi-threading.
#. ``CXX11 [Default: OFF]`` *Non-Windows platforms only*.
Although Ceres does not currently use C++11, it does use ``shared_ptr``
(required) and ``unordered_map`` (if available); both of which existed in the
previous iterations of what became the C++11 standard: TR1 & C++0x. As such,
Ceres can compile on pre-C++11 compilers, using the TR1/C++0x versions of
``shared_ptr`` & ``unordered_map``.
Note that on Linux (GCC & Clang), compiling against the TR1/C++0x versions:
``CXX11=OFF`` (the default) *does not* require ``-std=c++11`` when compiling
Ceres, *nor* does it require that any client code using Ceres use
``-std=c++11``. However, this will cause compile errors if any client code
that uses Ceres also uses C++11 (mismatched versions of ``shared_ptr`` &
``unordered_map``).
Enabling this option: ``CXX11=ON`` forces Ceres to use the C++11
versions of ``shared_ptr`` & ``unordered_map`` if they are available, and
thus imposes the requirement that all client code using Ceres also
compile with ``-std=c++11``. This requirement is handled automatically
through CMake target properties on the exported Ceres target for CMake >=
2.8.12 (when it was introduced). Thus, any client code which uses CMake will
automatically be compiled with ``-std=c++11``. **On CMake versions <
2.8.12, you are responsible for ensuring that any code which uses Ceres is
compiled with** ``-std=c++11``.
On OS X 10.9+, Clang will use the C++11 versions of ``shared_ptr`` &
``unordered_map`` without ``-std=c++11`` and so this option does not change
the versions detected, although enabling it *will* require that client code
compile with ``-std=c++11``.
The following table summarises the effects of the ``CXX11`` option:
=================== ========== ================ ======================================
OS CXX11 Detected Version Ceres & client code require ``-std=c++11``
=================== ========== ================ ======================================
Linux (GCC & Clang) OFF tr1 **No**
Linux (GCC & Clang) ON std **Yes**
OS X 10.9+ OFF std **No**
OS X 10.9+ ON std **Yes**
=================== ========== ================ ======================================
The ``CXX11`` option does does not exist for Windows, as there any new C++
features available are enabled by default, and there is no analogue of
``-std=c++11``.
#. ``BUILD_SHARED_LIBS [Default: OFF]``: By default Ceres is built as
a static library, turn this ``ON`` to instead build Ceres as a
shared library.
#. ``EXPORT_BUILD_DIR [Default: OFF]``: By default Ceres is configured solely
for installation, and so must be installed in order for clients to use it.
Turn this ``ON`` to export Ceres' build directory location into the
`user's local CMake package registry <http://www.cmake.org/cmake/help/v3.2/manual/cmake-packages.7.html#user-package-registry>`_
where it will be detected **without requiring installation** in a client
project using CMake when `find_package(Ceres) <http://www.cmake.org/cmake/help/v3.2/command/find_package.html>`_
is invoked.
#. ``BUILD_DOCUMENTATION [Default: OFF]``: Use this to enable building
the documentation, requires `Sphinx <http://sphinx-doc.org/>`_ and the
`sphinx_rtd_theme <https://pypi.python.org/pypi/sphinx_rtd_theme>`_
package available from the Python package index. In addition,
``make ceres_docs`` can be used to build only the documentation.
#. ``MSVC_USE_STATIC_CRT [Default: OFF]`` *Windows Only*: By default
Ceres will use the Visual Studio default, *shared* C-Run Time (CRT) library.
Turn this ``ON`` to use the *static* C-Run Time library instead.
Options controlling Ceres dependency locations
----------------------------------------------
Ceres uses the ``CMake``
`find_package <http://www.cmake.org/cmake/help/v3.2/command/find_package.html>`_
function to find all of its dependencies using
``Find<DEPENDENCY_NAME>.cmake`` scripts which are either included in Ceres
(for most dependencies) or are shipped as standard with ``CMake``
(for ``LAPACK`` & ``BLAS``). These scripts will search all of the "standard"
install locations for various OSs for each dependency. However, particularly
for Windows, they may fail to find the library, in this case you will have to
manually specify its installed location. The ``Find<DEPENDENCY_NAME>.cmake``
scripts shipped with Ceres support two ways for you to do this:
#. Set the *hints* variables specifying the *directories* to search in
preference, but in addition, to the search directories in the
``Find<DEPENDENCY_NAME>.cmake`` script:
- ``<DEPENDENCY_NAME (CAPS)>_INCLUDE_DIR_HINTS``
- ``<DEPENDENCY_NAME (CAPS)>_LIBRARY_DIR_HINTS``
These variables should be set via ``-D<VAR>=<VALUE>``
``CMake`` arguments as they are not visible in the GUI.
#. Set the variables specifying the *explicit* include directory
and library file to use:
- ``<DEPENDENCY_NAME (CAPS)>_INCLUDE_DIR``
- ``<DEPENDENCY_NAME (CAPS)>_LIBRARY``
This bypasses *all* searching in the
``Find<DEPENDENCY_NAME>.cmake`` script, but validation is still
performed.
These variables are available to set in the ``CMake`` GUI. They
are visible in the *Standard View* if the library has not been
found (but the current Ceres configuration requires it), but
are always visible in the *Advanced View*. They can also be
set directly via ``-D<VAR>=<VALUE>`` arguments to ``CMake``.
Building using custom BLAS & LAPACK installs
----------------------------------------------
If the standard find package scripts for ``BLAS`` & ``LAPACK`` which ship with
``CMake`` fail to find the desired libraries on your system, try setting
``CMAKE_LIBRARY_PATH`` to the path(s) to the directories containing the
``BLAS`` & ``LAPACK`` libraries when invoking ``CMake`` to build Ceres via
``-D<VAR>=<VALUE>``. This should result in the libraries being found for any
common variant of each.
If you are building on an exotic system, or setting ``CMAKE_LIBRARY_PATH``
does not work, or is not appropriate for some other reason, one option would be
to write your own custom versions of ``FindBLAS.cmake`` &
``FindLAPACK.cmake`` specific to your environment. In this case you must set
``CMAKE_MODULE_PATH`` to the directory containing these custom scripts when
invoking ``CMake`` to build Ceres and they will be used in preference to the
default versions. However, in order for this to work, your scripts must provide
the full set of variables provided by the default scripts. Also, if you are
building Ceres with ``SuiteSparse``, the versions of ``BLAS`` & ``LAPACK``
used by ``SuiteSparse`` and Ceres should be the same.
.. _section-using-ceres:
Using Ceres with CMake
======================
In order to use Ceres in client code with CMake using
`find_package() <http://www.cmake.org/cmake/help/v3.2/command/find_package.html>`_
then either:
#. Ceres must have been installed with ``make install``.
If the install location is non-standard (i.e. is not in CMake's default
search paths) then it will not be detected by default, see:
:ref:`section-local-installations`.
Note that if you are using a non-standard install location you should
consider exporting Ceres instead, as this will not require any extra
information to be provided in client code for Ceres to be detected.
#. Or Ceres' build directory must have been exported
by enabling the ``EXPORT_BUILD_DIR`` option when Ceres was configured.
As an example of how to use Ceres, to compile `examples/helloworld.cc
<https://ceres-solver.googlesource.com/ceres-solver/+/master/examples/helloworld.cc>`_
in a separate standalone project, the following CMakeList.txt can be used:
.. code-block:: cmake
cmake_minimum_required(VERSION 2.8)
project(helloworld)
find_package(Ceres REQUIRED)
include_directories(${CERES_INCLUDE_DIRS})
# helloworld
add_executable(helloworld helloworld.cc)
target_link_libraries(helloworld ${CERES_LIBRARIES})
Irrespective of whether Ceres was installed or exported, if multiple versions
are detected, set: ``Ceres_DIR`` to control which is used. If Ceres was
installed ``Ceres_DIR`` should be the path to the directory containing the
installed ``CeresConfig.cmake`` file (e.g. ``/usr/local/share/Ceres``). If
Ceres was exported, then ``Ceres_DIR`` should be the path to the exported
Ceres build directory.
Specify Ceres version
---------------------
Additionally, when CMake has found Ceres it can optionally check the package
version, if it has been specified in the `find_package()
<http://www.cmake.org/cmake/help/v3.2/command/find_package.html>`_
call. For example:
.. code-block:: cmake
find_package(Ceres 1.2.3 REQUIRED)
.. _section-local-installations:
Local installations
-------------------
If Ceres was installed in a non-standard path by specifying
``-DCMAKE_INSTALL_PREFIX="/some/where/local"``, then the user should add
the **PATHS** option to the ``find_package()`` command, e.g.,
.. code-block:: cmake
find_package(Ceres REQUIRED PATHS "/some/where/local/")
Note that this can be used to have multiple versions of Ceres
installed. However, particularly if you have only a single version of Ceres
which you want to use but do not wish to install to a system location, you
should consider exporting Ceres using the ``EXPORT_BUILD_DIR`` option instead
of a local install, as exported versions of Ceres will be automatically detected
by CMake, irrespective of their location.
Understanding the CMake Package System
----------------------------------------
Although a full tutorial on CMake is outside the scope of this guide, here
we cover some of the most common CMake misunderstandings that crop up
when using Ceres. For more detailed CMake usage, the following references are
very useful:
- The `official CMake tutorial <http://www.cmake.org/cmake-tutorial/>`_
Provides a tour of the core features of CMake.
- `ProjectConfig tutorial <http://www.cmake.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file>`_ and the `cmake-packages documentation <http://www.cmake.org/cmake/help/git-master/manual/cmake-packages.7.html>`_
Cover how to write a ``ProjectConfig.cmake`` file, discussed below, for
your own project when installing or exporting it using CMake. It also covers
how these processes in conjunction with ``find_package()`` are actually
handled by CMake. The
`ProjectConfig tutorial <http://www.cmake.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file>`_
is the older style, currently used by Ceres for compatibility with older
versions of CMake.
.. NOTE :: **Targets in CMake.**
All libraries and executables built using CMake are represented as
*targets* created using
`add_library()
<http://www.cmake.org/cmake/help/v3.2/command/add_library.html>`_
and
`add_executable()
<http://www.cmake.org/cmake/help/v3.2/command/add_executable.html>`_.
Targets encapsulate the rules and dependencies (which can be other targets)
required to build or link against an object. This allows CMake to
implicitly manage dependency chains. Thus it is sufficient to tell CMake
that a library target: ``B`` depends on a previously declared library target
``A``, and CMake will understand that this means that ``B`` also depends on
all of the public dependencies of ``A``.
When a project like Ceres is installed using CMake, or its build directory is
exported into the local CMake package registry
(see :ref:`section-install-vs-export`), in addition to the public
headers and compiled libraries, a set of CMake-specific project configuration
files are also installed to: ``<INSTALL_ROOT>/share/Ceres`` (if Ceres is
installed), or created in the build directory (if Ceres' build directory is
exported). When `find_package
<http://www.cmake.org/cmake/help/v3.2/command/find_package.html>`_
is invoked, CMake checks various standard install locations (including
``/usr/local`` on Linux & UNIX systems), and the local CMake package registry
for CMake configuration files for the project to be found (i.e. Ceres in the
case of ``find_package(Ceres)``). Specifically it looks for:
- ``<PROJECT_NAME>Config.cmake`` (or ``<lower_case_project_name>-config.cmake``)
Which is written by the developers of the project, and is configured with
the selected options and installed locations when the project is built and
defines the CMake variables: ``<PROJECT_NAME>_INCLUDE_DIRS`` &
``<PROJECT_NAME>_LIBRARIES`` which are used by the caller to import
the project.
The ``<PROJECT_NAME>Config.cmake`` typically includes a second file installed to
the same location:
- ``<PROJECT_NAME>Targets.cmake``
Which is autogenerated by CMake as part of the install process and defines
**imported targets** for the project in the caller's CMake scope.
An **imported target** contains the same information about a library as a CMake
target that was declared locally in the current CMake project using
``add_library()``. However, imported targets refer to objects that have already
been built by a different CMake project. Principally, an imported
target contains the location of the compiled object and all of its public
dependencies required to link against it. Any locally declared target can
depend on an imported target, and CMake will manage the dependency chain, just
as if the imported target had been declared locally by the current project.
Crucially, just like any locally declared CMake target, an imported target is
identified by its **name** when adding it as a dependency to another target.
Thus, if in a project using Ceres you had the following in your CMakeLists.txt:
.. code-block:: cmake
find_package(Ceres REQUIRED)
message("CERES_LIBRARIES = ${CERES_LIBRARIES}")
You would see the output: ``CERES_LIBRARIES = ceres``. **However**, here
``ceres`` is an **imported target** created when ``CeresTargets.cmake`` was
read as part of ``find_package(Ceres REQUIRED)``. It does **not** refer
(directly) to the compiled Ceres library: ``libceres.a/so/dylib/lib``. This
distinction is important, as depending on the options selected when it was
built, Ceres can have public link dependencies which are encapsulated in the
imported target and automatically added to the link step when Ceres is added
as a dependency of another target by CMake. In this case, linking only against
``libceres.a/so/dylib/lib`` without these other public dependencies would
result in a linker error.
Note that this description applies both to projects that are **installed**
using CMake, and to those whose **build directory is exported** using
`export() <http://www.cmake.org/cmake/help/v3.2/command/export.html>`_
(instead of
`install() <http://www.cmake.org/cmake/help/v3.2/command/install.html>`_).
Ceres supports both installation and export of its build directory if the
``EXPORT_BUILD_DIR`` option is enabled, see :ref:`section-customizing`.
.. _section-install-vs-export:
Installing a project with CMake vs Exporting its build directory
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
When a project is **installed**, the compiled libraries and headers are copied
from the source & build directory to the install location, and it is these
copied files that are used by any client code. When a project's build directory
is **exported**, instead of copying the compiled libraries and headers, CMake
creates an entry for the project in the
`user's local CMake package registry <http://www.cmake.org/cmake/help/v3.2/manual/cmake-packages.7.html#user-package-registry>`_,
``<USER_HOME>/.cmake/packages`` on Linux & OS X, which contains the path to
the project's build directory which will be checked by CMake during a call to
``find_package()``. The effect of which is that any client code uses the
compiled libraries and headers in the build directory directly, **thus not
requiring the project to be installed to be used**.
Installing / Exporting a project that uses Ceres
--------------------------------------------------
As described in `Understanding the CMake Package System`_, the contents of
the ``CERES_LIBRARIES`` variable is the **name** of an imported target which
represents Ceres. If you are installing / exporting your *own* project which
*uses* Ceres, it is important to understand that:
**imported targets are not (re)exported when a project which imported them is
exported**.
Thus, when a project ``Foo`` which uses Ceres is exported, its list of
dependencies as seen by another project ``Bar`` which imports ``Foo`` via:
``find_package(Foo REQUIRED)`` will contain: ``ceres``. However, the
definition of ``ceres`` as an imported target is **not (re)exported** when Foo
is exported. Hence, without any additional steps, when processing ``Bar``,
``ceres`` will not be defined as an imported target. Thus, when processing
``Bar``, CMake will assume that ``ceres`` refers only to:
``libceres.a/so/dylib/lib`` (the compiled Ceres library) directly if it is on
the current list of search paths. In which case, no CMake errors will occur,
but ``Bar`` will not link properly, as it does not have the required public link
dependencies of Ceres, which are stored in the imported target defintion.
The solution to this is for ``Foo`` (i.e., the project that uses Ceres) to
invoke ``find_package(Ceres)`` in ``FooConfig.cmake``, thus ``ceres`` will be
defined as an imported target when CMake processes ``Bar``. An example of the
required modifications to ``FooConfig.cmake`` are show below:
.. code-block:: cmake
# Importing Ceres in FooConfig.cmake using CMake 2.8.x style.
#
# When configure_file() is used to generate FooConfig.cmake from
# FooConfig.cmake.in, @Ceres_DIR@ will be replaced with the current
# value of Ceres_DIR being used by Foo. This should be passed as a hint
# when invoking find_package(Ceres) to ensure that the same install of
# Ceres is used as was used to build Foo.
set(CERES_DIR_HINTS @Ceres_DIR@)
# Forward the QUIET / REQUIRED options.
if (Foo_FIND_QUIETLY)
find_package(Ceres QUIET HINTS ${CERES_DIR_HINTS})
elseif (Foo_FIND_REQUIRED)
find_package(Ceres REQUIRED HINTS ${CERES_DIR_HINTS})
else ()
find_package(Ceres HINTS ${CERES_DIR_HINTS})
endif()
.. code-block:: cmake
# Importing Ceres in FooConfig.cmake using CMake 3.x style.
#
# In CMake v3.x, the find_dependency() macro exists to forward the REQUIRED
# / QUIET parameters to find_package() when searching for dependencies.
#
# Note that find_dependency() does not take a path hint, so if Ceres was
# installed in a non-standard location, that location must be added to
# CMake's search list before this call.
include(CMakeFindDependencyMacro)
find_dependency(Ceres)
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