# Installation

## Building from Source

Building Meep directly from the source code can be challenging for users unfamiliar with building Unix software. This is mainly because of the numerous prerequisites that must be installed as well as the need to specify in the build scripts where these packages are to be found.

Meep's build systems uses the standard GNU Autotools ./configure && make && make install machinery, but requires a number of prerequisites in order to obtain a full-featured Meep installation: MPB, Libctl, Harminv, libGDSII, MPI, OpenMP, HDF5, Python, and Guile. MPB and Harminv, in turn, require LAPACK and BLAS and FFTW to be installed.

Gzipped tarballs of stable versions of the source are available on the releases page, and you can also do a git clone of the master branch of the Meep repository on Github if you have Autotools installed. For more information, see Build From Source.

## Conda Packages

### Official Releases

The recommended way to install PyMeep is using the Conda package manager. The precompiled binaries run as fast or faster than the typical build from source, are simple to install, can be upgraded easily, and take advantage of newer compilers and dependencies than those available in typical systems (e.g., gcc 7.3.0 vs. Ubuntu 16.04's 5.4; a gap of nearly three years of advances in compiler optimization). Obviously, building from source can still provide advantages if you have access to special hardware or performance libraries that require specific compiler flags (e.g., icc); building from source is also required if you are interested in working on the Meep source code, are performing system-wide installations on a server, or are using systems unsupported by Conda (e.g., supercomputers with Cray MPI).

Binary packages for serial and parallel PyMeep on Linux and macOS are currently available (64 bit architectures only), and are updated with each new Meep release. Note: the Conda packages will not work on native Windows (unless you install the Ubuntu terminal app) and do not include the Scheme interface which must be built from source. The easiest way to get started is to install Miniconda, which comes with everything necessary to create Python environments with Conda. For example, to install Miniconda with Python 3 on Linux:

wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh
bash miniconda.sh -b -p <desired_prefix>
export PATH=<desired_prefix>/bin:$PATH  Next, we create a Conda environment for PyMeep (serial version) to isolate it from other Python libraries that may be installed. conda create -n mp -c conda-forge pymeep pymeep-extras  This creates an environment called "mp" (you can name this anything you like) with PyMeep and all its dependencies. This will default to the version of Python in your Miniconda installation. The optional "pymeep-extras" package contains scipy, matplotlib, autograd, and other packages necessary if you want to try out the tutorial examples. Next, we need to activate the environment before we can start using it. conda activate mp  Now, python -c 'import meep' (or python3 -c 'import meep') should work, and you can try running some of the examples in meep/python/examples. Note: There is currently an issue with openblas 0.3.5 that causes segmentation faults on newer Skylake X-series cpus. If import meep results in an "illegal instruction" error, downgrade openblas to version 0.3.4 as follows: conda install -c conda-forge openblas=0.3.4  Warning: The pymeep package is built to work with OpenBLAS, which means numpy should also use OpenBLAS. Since the default numpy is built with MKL, installing other packages into the environment may cause conda to switch to an MKL-based numpy. This can cause segmentation faults when calling MPB. To work around this, you can make sure the no-mkl conda package is installed, make sure you're getting packages from the conda-forge channel (they use OpenBLAS for everything), or as a last resort, run import meep before importing any other library that is linked to MKL. When installing additional packages into the meep environment, you should always try to install using the -c conda-forge flag. conda can occasionally be too eager in updating packages to new versions which can leave the environment unstable. If running conda install -c conda-forge <some-package> attempts to replace conda-forge packages with equivalent versions from the defaults channel, you can force it to only use channels you specify (i.e., arguments to the -c flag) with the --override-channels flag. Installing parallel PyMeep follows the same pattern, but the package "build string" must be specified to bring in the MPI variant: conda create -n pmp -c conda-forge pymeep=*=mpi_mpich_* conda activate pmp  The first * requests the latest version of Pymeep, and the mpi_mpich_* says to get a version that includes "mpi_mpich" in the build string (the packages are currently built with the MPICH implementation of MPI). The environment includes mpi4py, so you can run an MPI job with 4 processes like this: mpirun -np 4 python <script_name>.py  If you run into issues, make sure your PYTHONPATH environment variable is unset. Note: If you experience crashes when using matplotlib on macOS, try importing meep before importing matplotlib. In addition add the following line to your ~/.matplotlib/matplotlibrc file to force the TkAgg backend: backend: TkAgg  Note: For pymeep-parallel on macOS, a bug in openmpi requires that the environment variable TMPDIR be set to a short path like /tmp. Without this workaround, you may see errors similar to this: [laptop:68818] [[53415,0],0] ORTE_ERROR_LOG: Bad parameter in file ../../orte/orted/pmix/pmix_server.c at line 264 [laptop:68818] [[53415,0],0] ORTE_ERROR_LOG: Bad parameter in file ../../../../../orte/mca/ess/hnp/ess_hnp_module.c at line 666  Note: To update, pymeep, you can do conda update -c conda-forge pymeep. If you run into problems (e.g. some other update has interfered with your environment), you can instead create a new environment from scratch each time. #### Older Releases Older releases of PyMeep are available on the conda-forge channel. The full list of available versions is here. Examples: # Create an environment with the serial version of pymeep 1.8.0 conda create -n mp1.8 -c conda-forge pymeep=1.8.0 # Create an environment with the parallel version of pymeep 1.9.0 conda create -n pmp1.9 -c conda-forge pymeep=1.9.0=mpi_mpich_*  Note that parallel (MPI) versions are only available with pymeep >= 1.8.0. ### Version Number You can determine the version number as well as the most recent commit of the Meep module via: import meep as mp print(mp.__version__)  This will show something like 1.11.0-1-g415bc8eb where the first three digits (1.11.0) refer to a stable tarball release, the following digit is the number of commits after this stable release, and the eight characters following the g in the final string refer to the commit hash. ### Non-Networked Systems To install the PyMeep Conda package on a non-networked system, using the bz2 tarball of the official release will not work without the dependencies. A possible workaround is Conda-Pack. ## Installation on Linux For most Linux distributions, there should be precompiled packages for most of Meep's prerequisites below, and we highly recommend installing those prerequisites using the available packages for your system whenever possible. Using precompiled packages means that you don't have to worry about how to install things manually. You are using packages which have already been tweaked to work well with your system, and usually your packages will be automatically upgraded when you upgrade the rest of your system. There are upcoming packages for Meep version 1.17.1 with Python interface for Ubuntu 21.04 ("Hirsute Hippo") (serial and parallel) and Debian 11 ("Bullseye") (serial and parallel) which will be released in April 2021. In the meantime, the following dependencies are already available as precompiled packages: BLAS and LAPACK possibly as part of a package for Atlas BLAS, Guile, MPI, and HDF5. One thing to be careful of is that many distributions split packages into two parts: one main package for the libraries and programs, and a devel package for header files and other things needed to compile software using those libraries. You will need to install both. So, for example, you will probably need both a guile package (probably installed by default) and a guile-dev or guile-devel package (probably not installed by default), and similarly for HDF5 etcetera. You will probably also want to install a libpng-dev or libpng-devel package in order to compile the h5topng utility in h5utils. ## Installation from source on macOS Most macOS users will probably want to install via the Conda packages as described above. It is also possible to compile Meep from source, however. Since macOS is, at its heart, a Unix system, one can, in principle compile and install Meep and all its prerequisites just as on any other Unix system. However, this process is much easier using the Homebrew package to install most of the prerequisites, since it will handle dependencies and other details for you. You will need administrator privileges on your Mac. The first steps are: • Install Xcode, the development/compiler package from Apple: type xcode-select --install in the Terminal. • Install Homebrew: download from the Homebrew site and follow the instructions there. • Run the following commands in the terminal to compile and install the prerequisites. This may take a while to complete because it will install lots of other stuff first brew doctor brew install hdf5 guile fftw gsl libpng autoconf automake libtool swig  If you don't have your own Python installation (e.g. via miniforge), you should install numpy and matplotlib and other packages used by Meep and its tests: HDF5_DIR="$(brew --prefix hdf5)" pip3 install numpy matplotlib scipy autograd jax parameterized h5py


Now, install the Harminv, libctl, MPB, and Meep packages from source. Download Harminv and, in the harminv directory, do:

./configure CPPFLAGS="-I$(brew --prefix)/include" LDFLAGS="-L$(brew --prefix)/lib" PYTHON=python3 && make && sudo make install


Use the same commands for libctl, MPB, (optionally) h5utils, (optionally) libGDSII, and Meep. For more detailed information, see Build From Source. Note that if you are installing from a git clone rather than from a release .tar.gz file, you will need to first run sh autogen.sh, and you should add --enable-maintainer-mode to the configure arguments.

You are done, and can now run Meep (Scheme interface) just by typing meep. You can run make check in the meep directory if you want to perform a self-test.

Native Windows installation is currently unsupported. The recommended procedure is to install Ubuntu using the Windows Subsystem for Linux. This gives you access to a bash terminal running Ubuntu from within Windows. From there you can install the Conda packages as described above. The drawback is that you can't see plots from matplotlib (though saving them to disk and opening them from Windows works fine). The easiest way around this is to add the jupyter package to the conda create ... command. This will allow you to run a Jupyter notebook in the browser, and from there you can visualize plots interactively.