MESA

Modules for Experiments
in Stellar Astrophysics

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What should you do before using MESA?

This page has information to help you prepare for using MESA. It is important to remember that MESA is under construction -- and probably will be for the indefinite future.

Jakub Ostrowski has created a MESA installation tutorial on YouTube that will visually guide you through these instructions. You may want to take a look!

Look through this presentation; skim the MESA papers

Before you use MESA, you should get a feel for what it can do.

For a brief summary of the capabilities of MESA, take a look at this presentation by Matteo Cantiello. (He has also provided a Keynote version.)

The full capabilities of MESA are documented in the instrument papers. Looking through the figures will give you a feel for the broad range of problems that can be studied using MESA.

Join the mailing list

The "how-to" documentation is largely embedded in the experience of the community of users. Therefore the first step to becoming a MESA user is to join the mesa-users mailing list. (Click the preceding link and complete the "Subscribing to mesa-users" section of the form.)

If you have requests for help, you should post your questions to mesa-users. You should also search the mailing list archives to look for similar questions that may have been asked in the past. And once you begin to know how to use MESA, please help by responding to posts on the list.

Check the MESA map

Take a look at the maps below to see the locations of MESA users. To have your location added, email Frank Timmes.

Map of MESA users (World)

Map of MESA users (USA)

Ensure your system meets the minimum hardware requirements

The minimum system requirements for MESA are:

Most laptop or desktop computers built in the last three years will satisfy these requirements.

Install the prerequisites (MESA SDK)

Before you can do an install for MESA, you need to get the prerequisites. The MESA SDK provided by Rich Townsend simplifies this process. It provides a prebuilt set of compilers and run-time libraries that should make your MESA install go smoothly. Visit the MESA SDK website for the details of setting it up.

If you would prefer to use ifort (the MESA SDK uses gfortran), that is also an option, so long as you use ifort 14 or later. Even if you choose to use ifort, you should still visit the MESA SDK website to get a feel for the other MESA requirements.

Not using the MESA SDK means you'll need to replace the file $MESA_DIR/utils/makefile_header with a version customized to your system. There's a template to get you started at $MESA_DIR/utils/makefile_header_non_mesasdk.

Regardless of whether you use the MESA SDK or ifort, and whether your machine runs mac or linux, the output of MESA should be bit-for-bit identical. If it's not, Bill considers it to be a bug. (This has been the case since Release 5819 in early January 2014.)

Download MESA

The simplest way to get the MESA software is to download a zip file of the latest MESA release.

The compressed file is about 1GB, so don't worry if it takes a little while to download. If you are experiencing slow download speeds, you may want to change which mirror you are using. (After you select a zipfile to download, click the "try another mirror" link near the top of the page.)

The unzipped and installed package will be large, so make sure you have at least 10 GB free on your disk.

When you unzip the file, it will create a directory named mesa-r9575. This will be your main MESA directory. You are free to rename it, just make sure to set MESA_DIR accordingly (see the next section).

You can also download zip files of older MESA releases. If you plan to do so, please read this FAQ entry.

If you'd prefer, you can instead checkout a copy of MESA from its subversion repository, using the command:

svn co -r 9575 svn://svn.code.sf.net/p/mesa/code/trunk mesa

Note that there might be newer versions out there in the svn repository, but they are probably untested, unstable, and generally not at all what you want, so please stick to the officially released ones. To repeat: always use "-r", and to make sure that you get an officially released version always follow "-r" with the version number of an official MESA release.

Set your environment variables

The easiest way to make sure that your system is always configured appropriately is to define the neccessary environment variables in your shell start-up file. The file that you need to edit will depend on which shell you're using. (If you don't set the environment variables in your shell start-up file, you will need to re-define them each time you open a new shell.)

The exact paths will vary depending on where you installed MESA and which operating system that you are using. After you add these commands to your shell startup file, don't forget to open a new shell (or source the startup file in an existing one).

You will need to mix and match different aspects of the following example configurations depending on your shell, your operating system, and your installation method.

Here is an example from a machine that uses bash as its shell (and hence uses export to set variables), runs OS X, and downloaded MESA via a zip file:

# set MESA_DIR to be the directory to which you downloaded MESA
export MESA_DIR=/Users/jschwab/Software/mesa-r9575

# set OMP_NUM_THREADS to be the number of cores on your machine
export OMP_NUM_THREADS=2

# you should have done this when you set up the MESA SDK
export MESASDK_ROOT=/Applications/mesasdk
source $MESASDK_ROOT/bin/mesasdk_init.sh

Here is an example from a machine that uses csh as its shell (and hence uses setenv to set variables), runs Linux, and downloaded MESA via SVN:

# set MESA_DIR to be the directory to which you downloaded MESA
setenv MESA_DIR /home/jschwab/Software/mesa

# set OMP_NUM_THREADS to be the number of cores on your machine
setenv OMP_NUM_THREADS 4

# you should have done this when you set up the MESA SDK
setenv MESASDK_ROOT /opt/mesasdk
source $MESASDK_ROOT/bin/mesasdk_init.csh

One caveat is that if you put the MESA SDK in your shell profile, you'll always be using the MESA SDK supplied version of gcc which may be a compatibility issue if you work with other other codes. Alternative (unsupported) initialization scripts are available here.

Compile MESA

Now we are ready to compile the code. This will take a little while, so do something else for a bit or get up and get a cup of coffee.

cd $MESA_DIR
./install

Note that there is no reason to use sudo. The MESA install does not require root privileges. Once it is done, you should receive the message

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mesa installation was successful.

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If so, move on to "getting started". If not, take a look at "troubleshooting".