Getting started#
This section goes through the process of getting, installing, and starting to run BOUT++.
The quickest way to get started is to use a pre-built binary. These take care of all dependencies, configuration and compilation. See section Docker image.
The remainder of this section will go through the following steps to manually install BOUT++. Only the basic functionality needed to use BOUT++ is described here; the next section (Advanced installation options) goes through more advanced options, configurations for particular machines, and how to fix some common problems.
Note: In this manual commands to run in a BASH shell will begin with ’$’, and commands specific to CSH with a ’%’.
Pre-built binaries#
Docker image#
Docker is a widely used container system, which packages together the operating system environment, libraries and other dependencies into an image. This image can be downloaded and run reproducibly on a wide range of hosts, including Windows, Linux and OS X. Here is the starting page for instructions on installing Docker.
The BOUT++ docker images are hosted on dockerhub for some releases and snapshots. Check the list of BOUT-next tags if you want a recent version of BOUT++ “next” (development) branch. First download the image:
$ sudo docker pull boutproject/boutproject/bout-next:9f4c663-petsc
then run:
$ sudo docker run --rm -it boutproject/bout-next:9f4c663-petsc
This should give a terminal in a “boutuser” home directory, in which there is “BOUT-next”, containing BOUT++ configured and compiled with NetCDF, SUNDIALS, PETSc and SLEPc. Python 3 is also installed, with ipython, NumPy, Scipy and Matplotlib libaries. To plot to screen an X11 display is needed. Alternatively a shared directory can be created to pass files between the docker image and host. The following commands both enable X11 and create a shared directory:
$ mkdir shared
$ sudo docker run --rm -it \
-e DISPLAY -v $HOME/.Xauthority:/home/boutuser/.Xauthority --net=host \
-v $PWD/shared:/home/boutuser/bout-img-shared \
boutproject/bout-next:9f4c663-petsc
This should enable plotting from python, and files in the docker image put in “/home/boutuser/bout-img-shared” should be visible on the host in the “shared” directory.
If this is successful, then you can skip to section Running BOUT++.
Obtaining BOUT++#
BOUT++ is hosted publicly on github at boutproject/BOUT-dev. You can the latest stable version from boutproject/BOUT-dev. If you want to develop BOUT++, you should use git to clone the repository. To obtain a copy of the latest version, run:
$ git clone https://github.com/boutproject/BOUT-dev.git
which will create a directory BOUT-dev
containing the code:
$ cd BOUT-dev
To get the latest changes later, go into the BOUT-dev
directory and run:
$ git pull
Development is done on the “next” branch, which you can checkout with:
$ git checkout next
Installing dependencies#
The bare-minimum requirements for compiling and running BOUT++ are:
A C++ compiler that supports C++14
An MPI compiler such as OpenMPI (www.open-mpi.org/), MPICH ( https://www.mpich.org/)
The NetCDF library (https://www.unidata.ucar.edu/downloads/netcdf)
The FFTW-3 library (http://www.fftw.org/)
is also strongly recommended. Fourier transforms are used for some
derivative methods, as well as the ShiftedMetric
parallel transform
which is used in the majority of BOUT++ tokamak simulations. Without
FFTW-3, these options will not be available.
Note
If you use an Intel compiler, you must also make sure that you have a version of GCC that supports C++14 (GCC 5+).
On supercomputers, or in other environments that use a module system, you may need to load modules for both Intel and GCC.
On a cluster or supercomputer#
If you are installing on a cluster or supercomputer then the MPI C++ compilers will
already be installed, and on Cray or IBM machines will probably be
called CC
and xlC
respectively.
On large facilities (e.g NERSC or Archer), the compilers and libraries
needed should already be installed, but you may need to load them to use them.
It is common to organise libraries using the modules
system, so try typing:
modules avail
to get a list of available modules. Some instructions for specific machines can be found in Machine-specific installation. See your system’s documentation on modules and which ones to load. If you don’t know, or modules don’t work, you can still install libraries in your home directory by following the instructions below for FFTW and NetCDF.
Ubuntu / Debian#
On Ubuntu or Debian distributions if you have administrator rights then you can install the basic dependencies with:
$ sudo apt-get install libmpich-dev libfftw3-dev libnetcdf-c++4-dev git make
To additionally build the Python interface, you need some Python packages:
$ sudo apt-get install python3 python3-distutils python3-pip python3-numpy python3-netcdf4 python3-scipy
$ pip3 install --user Cython
Further, the encoding for python needs to be utf8 - it may be required
to set export LC_CTYPE=C.utf8
.
If you do not have administrator rights, so can’t install packages, then you need to install these libraries from source into your home directory. See Advanced installation options for details on installing some of these.
Arch Linux#
$ pacman -S openmpi fftw netcdf-cxx make gcc
Fedora#
On Fedora the required libraries can be installed by running:
$ sudo dnf build-dep bout++
This will install all the dependencies that are used to install BOUT++ for fedora. Feel free to install only a subset of the suggested packages. For example, only mpich or openmpi is required. To load an mpi implementation type:
$ module load mpi
After that the mpi library is loaded. Precompiled binaries are available for fedora as well. To get precompiled BOUT++ run:
$ # install the mpich version - openmpi is available as well
$ sudo dnf install bout++-mpich-devel
$ # get the python3 modules - python2 is available as well
$ sudo dnf install python3-bout++
CMake#
BOUT++ uses the CMake build system generator. You will need CMake >= 3.17.
Note
It is possible to get the latest version of CMake using pip
:
$ pip install --user --upgrade cmake
or conda
:
$ conda install cmake
You may need to put ~/.local/bin
in your $PATH
CMake supports out-of-source builds by default, which are A Good Idea. Basic configuration with CMake looks like:
$ cmake -S . -B build
which creates a new directory build
. You can call this directory
anything you like, and you also put it anywhere you like, you just
need to specify the path to the BOUT++ source directory with the
-S
argument. This makes it very easy to keep two build directories
alongside one another, one with a debug build and one optimised, for
example.
After configuring the build directory, you can then compile BOUT++ with:
# Build the library
$ cmake --build build
# Build the library with 8 threads
$ cmake --build build -j 8
# Build the "blob2d" example
$ cmake --build build --target blob2d
By default, CMake will use makefiles
, and so it is possible to
also build BOUT++ with make
from the build directory – note that
you must still run cmake
once first to configure BOUT++:
$ cmake . -B build
$ cd build
$ make
Note
You might see some instructions in the documentation using make
– they should be run from the build
directory.
You can see what build options are available with:
$ cmake . -B build -LH
...
// Enable backtrace
BOUT_ENABLE_BACKTRACE:BOOL=ON
// Output coloring
BOUT_ENABLE_COLOR:BOOL=ON
// Enable OpenMP support
BOUT_ENABLE_OPENMP:BOOL=OFF
// Enable support for PETSc time solvers and inversions
BOUT_USE_PETSC:BOOL=OFF
...
CMake uses the -D<variable>=<choice>
syntax to control these
variables. You can set <package>_ROOT
to guide CMake in finding
the various optional third-party packages (except for PETSc/SLEPc,
which use _DIR
). Note that some packages have funny
captialisation, for example NetCDF_ROOT
! Use -LH
to see the
form that each package expects.
CMake understands the usual environment variables for setting the compiler, compiler/linking flags, as well as having built-in options to control them and things like static vs shared libraries, etc. See the CMake documentation for more infomation.
A more complicated CMake configuration command might look like:
$ CC=mpicc CXX=mpic++ cmake . -B build \
-DBOUT_USE_PETSC=ON -DPETSC_DIR=/path/to/petsc/ \
-DBOUT_USE_SLEPC=ON -DSLEPC_DIR=/path/to/slepc/ \
-DBOUT_USE_SUNDIALS=ON -DSUNDIALS_ROOT=/path/to/sundials \
-DBOUT_USE_NETCDF=ON -DNetCDF_ROOT=/path/to/netcdf \
-DBOUT_ENABLE_OPENMP=ON \
-DBOUT_ENABLE_SIGFPE=OFF \
-DCMAKE_BUILD_TYPE=Debug \
-DBUILD_SHARED_LIBS=ON
-DCMAKE_INSTALL_PREFIX=/path/to/install/BOUT++
If you wish to change the configuration after having built BOUT++
,
it’s wise to delete the CMakeCache.txt
file in the build
directory. The equivalent of make distclean
with CMake is to just
delete the entire build directory and reconfigure.
If you need to debug a CMake build, you can see the compile and link
commands which are being issued by adding --verbose
to the build
command:
$ cmake --build build --verbose
Common CMake Options#
The default build configuration options try to be sensible for new users and developers, but there are a few you probably want to set manually for production runs or for debugging:
CMAKE_BUILD_TYPE
: The default isRelWithDebInfo
, which builds an optimised executable with debug symbols included. Change this toRelease
to remove the debug symbols, orDebug
for an unoptimised build, but better debug experienceCHECK
: This sets the level of internal runtime checking done in the BOUT++ library, and ranges from 0 to 4 (inclusive). By default, this is 2, which aims to be a balance between useful checks and speed. Set this to 0 for faster production runs, and to 4 for more in-depth (and slower) checking.BOUT_UPDATE_GIT_SUBMODULE
: This is on by default, and ensures that the bundled git submodules are up-to-date. You should turn this off if you are using system versions, or if you run into problems updating the submodules.NetCDF_ROOT
: NetCDF is one of the few required, non-bundled dependencies. If CMake is having trouble finding netCDF, or the correct version, you should set this variable to the installed location of the netCDF C library.BOUT_BUILD_EXAMPLES
,BOUT_TESTS
: These two options are particularly useful for developers of the BOUT++ library, and for new users. You can turn them off to save some time configuring the library. By default, these are on, but the examples and tests are not built unless you specifically ask for them, using the targetsbuild-all-examples
andbuild-check
respectively.
Downloading Dependencies#
If you don’t have some dependencies installed, CMake can be used to download, configure and compile them alongside BOUT++.
For NetCDF, use -DBOUT_DOWNLOAD_NETCDF_CXX4=ON
For SUNDIALS, use -DBOUT_DOWNLOAD_SUNDIALS=ON
. If using ccmake
this option
may not appear initially. This automatically sets BOUT_USE_SUNDIALS=ON
, and
configures SUNDIALS to use MPI.
Bundled Dependencies#
BOUT++ bundles some dependencies, currently mpark.variant, fmt and
googletest. If you wish to
use an existing installation of mpark.variant
, you can set
-DBOUT_USE_SYSTEM_MPARK_VARIANT=ON
, and supply the installation
path using mpark_variant_ROOT
via the command line or environment
variable if it is installed in a non standard loction. Similarly for
fmt
, using -DBOUT_USE_SYSTEM_FMT=ON
and fmt_ROOT
respectively. To turn off both, you can set
-DBOUT_USE_GIT_SUBMODULE=OFF
.
The recommended way to use googletest
is to compile it at the same
time as your project, therefore there is no option to use an external
installation for that.
./configure#
Warning
As of BOUT++ 5.0, ./configure
is no longer supported and will
be removed in 6.0. Please switch to using CMake to build BOUT++.
To compile BOUT++, you first need to configure it.
Go into the BOUT-dev
directory and run:
$ ./configure
If this finishes by printing a summary, and paths for IDL, Python, and
Octave, then the libraries are set up and you can skip to the next
section. If you see a message
“ERROR: FFTW not found. Required by BOUT++
” then make sure
FFTW-3 is installed (See the previous section on installing dependencies ).
If FFTW-3 is installed in a non-standard location, you can specify the
directory with the –with-fftw=
option e.g:
$ ./configure --with-fftw=$HOME/local
Configure should now find FFTW, and search for the NetCDF library. If
configure finishes successfully, then skip to the next section, but if
you see a message NetCDF support disabled
then configure couldn’t
find the NetCDF library. This will be followed by a message
ERROR: At least one file format must be supported
. Check that you have
NetCDF installed (See the previous section on installing dependencies ).
Like the FFTW-3 library, if NetCDF is installed in a non-standard location then
you can specify the directory with the --with-netcdf=
option e.g.:
$ ./configure --with-fftw=$HOME/local --with-netcdf=$HOME/local
which should now finish successfully, printing a summary of the configuration:
Configuration summary
PETSc support: no
SLEPc support: no
IDA support: yes
CVODE support: yes
ARKODE support: yes
NetCDF support: yes
Parallel-NetCDF support: no
If not, see Advanced installation options for some things you can try to resolve common problems.
Working with an active conda
environment#
When conda
is used, it installs separate versions of several libraries. These
can cause warnings or even failures when linking BOUT++ executables. There are
several alternatives to deal with this problem:
* The simplest but least convenient option is to use conda deactivate
before
configuring, compiling, or running any BOUT++ program.
You might sometimes want to link to the conda-installed libraries. This is probably not ideal for production runs on an HPC system (as conda downloads binary packages that will not be optimized for specific hardware), but can be a simple way to get packages for testing or on a personal computer. In this case just keep your
conda
environment active, and with luck the libraries should be picked up by the standard search mechanisms.In case you do want a fully optimized and as-stable-as-possible build for production runs, it is probably best not to depend on any conda packages for compiling or running BOUT++ executables (restrict
conda
to providing Python packages for post-processing, and their dependencies). Passing-DBOUT_IGNORE_CONDA_ENV=ON
(defaultOFF
) excludes anything in the conda environment from CMake search paths. This should totally separate BOUT++ from theconda
environment.
Natural Language Support#
BOUT++ has support for languages other than English, using GNU gettext. If you are planning on installing BOUT++ (see Installing BOUT++ (experimental)) then this should work automatically, but if you will be running BOUT++ from the directory you downloaded it into, then configure with the option:
cmake . -DCMAKE_INSTALL_LOCALEDIR=$PWD/locale
This will enable BOUT++ to find the translations.
See Natural language support for details of how to switch language when running BOUT++ simulations.
Configuring analysis routines#
The BOUT++ installation comes with a set of useful routines which can be used to prepare inputs and analyse outputs. Most of this code is now in Python, though IDL was used for many years. Python is useful In particular because the test suite scripts and examples use Python, so to run these you’ll need python configured.
When the configure script finishes, it prints out the paths you need to get IDL, Python, and Octave analysis routines working. If you just want to compile BOUT++ then you can skip to the next section, but make a note of what configure printed out.
Python configuration#
To use Python, you will need the dependencies of the boututils and boutdata libraries. The simplest way to get these is to install the packages with pip:
$ pip install --user boutdata
or conda:
$ conda install boutdata
You can also install all the packages directly (see the documentation in the boututils and boutdata repos for the most up to date list) using pip:
$ pip install --user numpy scipy matplotlib sympy netCDF4 h5py future importlib-metadata
or conda:
$ conda install numpy scipy matplotlib sympy netcdf4 h5py future importlib-metadata
They may also be available from your Linux system’s package manager.
For example on Fedora:
$ sudo dnf install python3-boututils python3-boutdata
To use the versions of boututils
and boutdata
provided by BOUT++, the path to
tools/pylib
should be added to the PYTHONPATH
environment variable. This is not
necessary if you have installed the boututils
and boutdata
packages. Instructions
for doing this are printed at the end of the configure script, for example:
Make sure that the tools/pylib directory is in your PYTHONPATH
e.g. by adding to your ~/.bashrc file
export PYTHONPATH=/home/ben/BOUT/tools/pylib/:$PYTHONPATH
To test if this command has worked, try running:
$ python -c "import boutdata"
If this doesn’t produce any error messages then Python is configured correctly.
Note that boututils
and boutdata
are provided by BOUT++ as submodules, so versions
compatible with the checked out version of BOUT++ are downloaded into the
externalpackages
directory. These are the versions used by the tests run by make
check
even if you have installed boututils
and boutdata
on your system.
IDL configuration#
If you want to use IDL to analyse
BOUT++ outputs, then the IDL_PATH
environment variable should include the
tools/idllib/
subdirectory included with BOUT++.
The required command (for Bash) is printed at the end of the BOUT++ configuration:
$ export IDL_PATH=...
After running that command, check that idl
can find the analysis routines by running:
$ idl
IDL> .r collect
IDL> help, /source
You should see the function COLLECT
in the BOUT/tools/idllib
directory. If not, something is wrong with your IDL_PATH
variable.
On some machines, modifying IDL_PATH
causes problems, in which case
you can try modifying the path inside IDL by running:
IDL> !path = !path + ":/path/to/BOUT-dev/tools/idllib"
where you should use the full path. You can get this by going to the
tools/idllib
directory and typing pwd
. Once this is done
you should be able to use collect
and other routines.
Compiling BOUT++#
Once BOUT++ has been configured, you can compile the bulk of the code by
going to the BOUT-dev
directory and running:
$ cmake --build <build-directory>
where <build-directory>
is the path to the build directory
At the end of this, you should see a file libbout++.so
in the
lib/
subdirectory of the BOUT++ build directory. If you get an error,
please create an issue on Github
including:
Which machine you’re compiling on
The output from make, including full error message
The
CMakeCache.txt
file in the BOUT++ build directory
Running the test suite#
BOUT++ comes with three sets of test suites: unit tests, integrated tests and method of manufactured solutions (MMS) tests. The easiest way to run all of them is to simply do:
$ cmake --build <build-directory> --target check
Alternatively, if you just want to run one set of them individually, you can do:
$ cmake --build <build-directory> --target check-unit-tests
$ cmake --build <build-directory> --target check-integrated-tests
$ cmake --build <build-directory> --target check-mms-tests
Note: The integrated and MMS test suites currently uses the mpirun
command to launch the runs, so won’t work on machines which use a job
submission system like slurm or PBS.
These tests should all pass, but if not please create an issue on Github containing:
Which machine you’re running on
The
CMakeCache.txt
file in the BOUT++ build directoryThe
run.log.*
files in the directory of the test which failed
If the tests pass, congratulations! You have now got a working installation of BOUT++. Unless you want to use some experimental features of BOUT++, skip to section [sec-running] to start running the code.
Installing BOUT++ (experimental)#
Most BOUT++ users install and develop their own copies in their home directory, so do not need to install BOUT++ to a system directory. As of version 4.1 (August 2017), it is possible to install BOUT++ but this is not widely used and so should be considered experimental.
After configuring and compiling BOUT++ as above, BOUT++ can be installed
to system directories by running as superuser or sudo
:
$ sudo cmake --build <build-directory> --target install
Danger
Do not do this unless you know what you’re doing!
This will install the following files under /usr/local/
:
/usr/local/bin/bout-config
A script which can be used to query BOUT++ configuration and compile codes with BOUT++./usr/local/include/bout++/...
header files for BOUT++/usr/local/lib/libbout++.so
The main BOUT++ library/usr/local/lib/libpvode.so
and/usr/local/lib/libpvpre.so
, the PVODE library/usr/local/share/bout++/pylib/...
Python analysis routines/usr/local/share/bout++/idllib/...
IDL analysis routines
To install BOUT++ under a different directory, use the prefix=
flag e.g. to install in your home directory:
$ cmake --build <build-directory> --target install -DCMAKE_INSTALL_PREFIX=$HOME/local/
You can also specify this prefix when configuring, in the usual way (see ./configure):
$ cmake -S . -B <build-directory> -DCMAKE_INSTALL_PREFIX=$HOME/local/
$ cmake --build <build-directory> -j 4
$ cmake --build <build-directory> --target install
More control over where files are installed is possible by passing options to
cmake
, following the GNU conventions:
-DCMAKE_INSTALL_BINDIR=
sets wherebout-config
will be installed ( default/usr/local/bin
)-DCMAKE_INSTALL_INCLUDEDIR=
sets where thebout++/*.hxx
header files wil be installed (default/usr/local/include
)-DCMAKE_INSTALL_LIBDIR=
sets where thelibbout++.so
,libpvode.so
andlibpvpre.so
libraries are installed (default/usr/local/lib
)
After installing, that you can run bout-config
e.g:
$ bout-config --all
which should print out the list of configuration settings which bout-config
can provide.
If this doesn’t work, check that the directory containing bout-config
is in your PATH
.
The python and IDL analysis scripts can be configured using
bout-config
rather than manually setting paths as in
Configuring analysis routines. Add this line to your startup file
(e.g. $HOME/.bashrc
):
export PYTHONPATH=`bout-config --python`:$PYTHONPATH
note the back ticks around bout-config --python
not
quotes. Similarly for IDL:
export IDL_PATH=`bout-config --idl`:'<IDL_DEFAULT>':$IDL_PATH
More details on using bout-config are in the section on makefiles.