Windows Users

If you will be running C/C++/Fortran models on a Windows operatoring system, you will first need to install Microsoft Visual Studio, regardless of the installation method you end up using. Visual Studio Community can be downloaded for free from here. During installation, we recommend selecting the components below. If you forget to add something during the initial download, you can always modify the installation via the “Visual Studio Installer” program.

  • “Desktop development with C++” - Workload under “Windows” section

  • “MSVC v140 - VS 2015 C++ build tools (v14.00)” - Individual component under “Compilers, build tools, and runtimes” section.

If you do not use conda to install yggdrasil, you will also need to initialize the command line build tools in any prompt you will be calling yggdrasil from. This can be done by calling yggdrasil from a “VS2015 x64 Native Tools Developer Command Prompt”, or by locating the vsvarsall.bat script that comes with Visual Studio. Information on the developer prompt and how to locate the vsvarsall.bat script can be found here. The prompt/script used must enable the Visual Studio 2015 build tools (the specific year) to be compatible with the Python C library (see the discussion here). The VS 2015 tools prompt/script will be installed from within Visual Studio 2019 by selecting the components indicated above. On a 64bit Windows machine (assuming you will be using 64 bit Python), the command to initialize these tools within a regular command prompt will look something like this, but the exact path will vary with your particular installation:

$ call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" amd64


Mac Users

If you will be running C/C++/Fortran models, you will need to install the command line developer tools on Mac which provides several utilities for compilation and code management (e.g. clang, gcc, make, git). This article outlines how to check if they are installed and install them if they are not. It also describes how to install the Homebrew package manager, which will be useful for installing non-Python dependencies if you do not plan on using conda to install yggdrasil.

Development Installation

If you would like to contribute to yggdrasil, instructions on setting up a development environment can be found here.

Manual Installation


Before installing yggdrasil from pip or the cloned repository, you should manually install the non-Python dependencies, particularly the ZeroMQ C and C++ libraries and R packages (see below).


Windows Users Be warned that there is 260 character limit to the size of the PATH environment variable (see note here). If you modify the path (e.g. to add Python or the Python scripts directory), be sure that you do not exceed this limit. If you do, Windows will not report an error, but the characters past the limit will be ignored and so those directories will not be availble on the command prompt.


Windows Users If you do not use conda to install dependencies, we highly recommend installing two package managers, Chocolatey and vcpkg, to handle the installation of the non-Python dependencies. Instructions for installing Chocolatey can be found here and instructions for installing vcpkg can be found here.

If you do not want to use conda, you can install Python yourself and then install yggdrasil via pip or from the source code (See below). Python can be installed in a number of ways, but be sure that you get Python>=3.5. Installation methods include:

  • Executable installer from the Python Software Foundaction (Recommended for Windows)

  • Package manager, e.g. * brew install python3 on Mac (be sure to include the 3) * apt-get install python on Linux * choco install python3 on Windows

  • Microsoft Visual Studio

  • Microsoft Store (Windows only; we do not recommend this method as it can be difficult to get working correctly as it requires tracking down the Scripts direcotry modifying the path yourself, see discussion here)


Mac Users Python 2 is included on Mac as the default Python (as python), but python3 is what you will want to use (Python 2 has been deprecated). If you have Mac OS Catalina, you will already have Python 3, but you may need to enable developer tools to use it. You can check to see if Python 3 is installed (or prompt the developer tool installation) by running python3 --version and python --version. If these commands do not return the same version, you will need to be sure to always use python3 and pip3 during installation (as opposed to the versions of the executables without the 3), or set Python 3 to be the default version of Python (see this article).


Windows Users If you install Python, but your prompt cannot locate Python (i.e. where python fails), you may need to add the directory containing the Python executable (and the Scripts directory inside that as discussed below) to you PATH environment variable (e.g. set path=%path%;C:\path\to\Python\directory or setx path=%path%;C:\path\to\Python\directory to make the change for new prompts). For more information on setting the path, including instruction on seting in via the GUI, see this article.

Once Python is installed, yggdrasil can be installed from the command line/prompt from either PyPI using pip

$ pip install yggdrasil-framework

or by cloning the Git repository on Github:

$ git clone --recurse-submodules

and then building the distribution.:

$ cd yggdrasil
$ pip install .

If the --recurse-submodules option was not included when cloning the repo, you will need to run the following from within the repository before calling python install to ensure that rapidjson is cloned as a submodule:

$ git submodule init
$ git submodule update

If you do not have admin privileges on the target machine, --user can be added to the end of either of the pip installation commands. When using the --user flag, you may need to add the directory containing the entry point scripts to your PATH environment variable in order to use yggdrasil command line tools (e.g. yggrun) without specifying their full path. Usually, this directory can be found using the following Python commands:

>>> import os
>>> from distutils.sysconfig import get_python_lib
>>> os.path.realpath(os.path.join(get_python_lib(), '..', '..', '..', 'bin'))


Windows Users If you used the Windows store to install Python, the above commands will not yield the correct scripts directory. It will be something along the lines of %userprofile%\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\Scripts

The displayed path can then be added either on the command link or in a startup script (e.g. .bashrc or .bash_profile), using one of the following:

$ export PATH=$PATH:<scripts_dir>  # (linux/osx, bash)
$ setenv PATH $PATH:<scripts_dir>  # (linux/osx, tcsh)
$ set PATH=%PATH%:<scripts_dir>   # (windows)

These commands will only add the directory to your path for the current session. For the change to be permanent on Linux/MacOS, the appropriate command from above can be added to your .bashrc or .bash_profile. On Windows (>=7), the following command will permanently modify your path:

$ setx PATH=%PATH%:<scripts_dir>

The changes will take affect the next time you open the terminal.

User Defined rapidjson

If you would like to use an existing installation of the rapidjson header-only library, you can pass the flag --rapidjson-include-dir=<user_defined_dir> to either of the pip installation commands from above with the location of the existing rapidjson include directory.

Additional Steps on Windows

As local communication on Windows is handled by ZeroMQ, running models written in C or C++ will require installing the ZeroMQ libraries for C and C++. If you install yggdrasil using conda, these will be installed automatically as dependencies. If you are not using conda, you will need to install them yourself.


Although not required, the ZeroMQ libraries are also recommended for message passing on Linux and MacOS operating systems as the IPC V message queues have default upper limits of 2048 bytes on some operating systems and will have to send larger messages piecemeal, adding to the message passing overhead. We recommend installing zeromq & czmq via apt on Linux (apt-get libczmq-dev libzmq3-dev) or Homebrew on Mac (brew install czmq zmq) if you do not use conda.

Installing via vcpkg

You can install the ZeroMQ C and C++ libraries via vcpkg (instructions for installing vcpkg found here. To do so run the following from your “VS2015 x64 Native Tools Developer Command Prompt”:

> vcpkg install czmq zeromq --triplet x64-windows


The --triplet x64-windows flag indicates a 64 bit version of Windows (the most common). If you have a 32 bit Windows installation or are using a 32 bit version of Python, omit the flag.

When you run yggconfig following installation of yggdrasil If you did not set the VCPKG_ROOT environment variable before installing vcpkg, you will need to add a flag indicating the location of the vcpkg installation when running yggconfig following installation of yggdrasil. e.g.:

> yggconfig --vcpkg-dir=C:\path\to\vcpkg\root\directory

If you do not do this, you will need to manually add the paths to the czmq and zeromq libraries/headers to your yggdrasil configuration file (See Configuration Options).

Building from Source

Instructions for installing the ZeroMQ C and C++ libraries can be found here At install (and any time yggconfig is called), yggdrasil will attempt to search for those libraries in those directories specified by the PATH, INCLUDE, and LIB environment variables. If yggdrasil complains that it cannot find these libraries, you can manually set them in your .yggdrasil.cfg file (See Configuration Options). If you install these libraries after installing yggdrasil you can re-configure yggdrasil and have it search for the libraries again by calling yggconfig from the command line or by setting the appropriate config options manually.

Additional Steps for Matlab Models

To run Matlab models, you will need an existing Matlab installation and license and the matlab executable must be on your path (i.e. you can call matlab from the command line and a Matlab interpreter will open). If not already available on the command line, you can enable it by adding the location of the executable to your path. The executable is usually located within a ‘bin’ directory within the directory that Matlab was installed. On Linux/Mac operating systems, this is done using the command:

$ export PATH=$PATH:</PATH/TO/MATLAB/bin/>

On Windows, this command should already be available.

While yggdrasil can now run Matlab models via the command line, it is still recommended that you install the Matlab engine for Python if you will be running Matlab models with yggdrasil frequently as using the engine reduces the time added to model startup by starting Matlab.

yggdrasil will attempt to install the Matlab engine for Python at install, but should it fail or if you want to use a non-default version of Matlab, you can also do it manually. Instructions for installing the Matlab engine as a Python package can be found on the Mathworks website. Once you have installed the Matlab engine as a python package, you can re-configure yggdrasil by calling yggconfig from the command line.


The version of Matlab that you are using will determine the versions of Python that you can use with yggdrasil. The chart below shows the versions of Python that are compatible with several versions of Matlab. If you are using an incompatible version, the instructions above for manually installing the Matlab engine as a Python package will fail with an error message indicating which versions of Python you can use.

Matlab Version

Max Python Version


2.7, 3.3, 3.4


2.7, 3.3, 3.4, 3.5


2.7, 3.3, 3.4, 3.5, 3.6


yggdrasil cannot currently run Matlab models if Matlab is installed via a Citrix environment as yggdrasil needs command line access to the Matlab executable and access to the environment in which Matlab models are run.

Additional Steps for R Models

Rtools (Windows only)

On Windows, if you do not install the R dependencies via conda, you will also need to install Rtools so that the R dependencies with C/C++/Fortran components can be compiled if they need to be installed from source. The Rtools installer and instructions for installing Rtools for R<4.0.0 can be found here. For R>=4.0.0, you will need to install Rtools40 instead (installer/instructions here).

R Interpreter

To run R models, you will need to install the R interpreter (we recommend R >= 3.5). If you installed yggdrasil using conda, this will be installed for you, but if you are not using conda, you will need to install R yourself along with the udunits package.


On Mac, this can be done via Homebrew:

$ brew install r
$ brew install udunits


On Linux this can be done via apt. Installing R >= 3.5 (recommended) requires first adding a source entry and key for your OS as shown below for for Xenial distribution of Ubuntu (Details on ubuntu, debian, redhat installation):

$ sudo add-apt-repository 'deb xenial-cran35/'
$ sudo apt-key adv --keyserver --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
$ sudo apt update
$ sudo apt-get install r-base r-base-dev
$ sudo apt-get install libudunits2-dev

If you don’t want the latest version, you can install the default using the last two lines on Ubuntu and Debian.


On Windows, you will need to download and run the installer. Links to the R 3.6 installer and additoinal information about the installation process on Windows can be found here.

R Dependencies

Even if you install the R interpreter yourself, yggdrasil will attempt to install the R dependencies it needs via CRAN when it is installed. If this fails, you may need to install these yourself from within the R interpreter. yggdrasil’s R dependencies include reticulate for calling Python from R, zeallot for allowing assignment of output to multiple variables, units for tracking physical units in R, bit64 for 64bit integers, and R6 for creating interface classes with teardown methods.

These packages can by installed from CRAN from the R interpreter.:

> install.packages("reticulate")
> install.packages("zeallot")
> install.packages("units")
> install.packages("bit64")
> install.packages("R6")


[MAC ONLY] If you have compilation issues when installing R packages on MacOS, check to make sure that which ar returns the system default (/usr/bin/ar). If you have another version of ar installed (e.g. through homebrew’s binutils), it may cause conflicts.


[MAC ONLY] If install.packages("units") fails with messages about the udunits library being missing and you installed udunits using homebrew as described above, then you can install the R units and point to the library by running:

> install.packages("units", configure.args = c("--with-udunits2-include=/usr/local/opt/udunits/include/", "--with-udunits2-lib=/usr/local/opt/udunits/lib/"))


[MAC ONLY?] If any install.packages calls fail with errors that look like those shown below, add the --no-multiarch install option to those passed (e.g. install.packages("R6", INSTALL_opts=c("--no-multiarch"))).:

*** arch - R
*** arch - R.dSYM
ERROR: loading failed for ‘R’, ‘R.dSYM’
ERROR: sub-architecture 'R' is not installed
ERROR: sub-architecture 'R.dSYM' is not installed

If you install R and/or the R dependencies after installing yggdrasil, you can complete yggdrasil’s R installation by running:

$ ygginstall R

from your terminal (Linux/Mac) or Anaconda prompt (Windows).


If you see errors along the lines of 'lib = "/usr/local/lib/R/site-library"' is not writable when running ygginstall R, it is likely that the directory R is attempting to install in requires staff privileges to edit. On Unix systems (Linux/Mac), if you have sudo access you can either add yourself to the staff group (e.g. sudo usermod -a -G staff your_user_name; then log off and back on) or add the --sudoR flag to the installation call (i.e. ygginstall R --sudoR). On windows, you can open R from an administrator prompt and install the dependencies from CRAN directly as shown above. If you do not have administrator access, you can pick a directory that you have write access to and add it to the list of paths checked by R for R libraries in your .Rprofile file (i.e. add .libPaths( c( "~/userLibrary" , .libPaths() ) )). This article describes what the .Rprofile file is and how to locate it. This article discusses this in the context of Rstudio and how to make these changes via the Rstudio GUI on Windows.

Additional Steps for RabbitMQ Message Passing

RabbitMQ connections allow messages to be passed between models when the models are not running on the same machine. To use these connections, the framework you must install the pika Python package and have access to a RabbitMQ server. If you have access to an existing RabbitMQ server, the information for that server be provided via the yggdrasil config file (See Configuration Options for information on setting config options).

Starting a local RabbitMQ Server is also relatively easy. Details on downloading, installing, and starting a RabbitMQ server can be found here. The default values for RabbitMQ related properties in the config file are set to the defaults for starting a RabbitMQ server.

Additional Steps for OpenSimRoot

If you would like to use OpenSimRoot, you will need to install GNU make. If you are on Linux/Mac or used conda to install yggdrasil it is likely that it will already be installed (you can run make --version to check). If it is not installed, and you are using a Mac OS, you can install XCode and the command line developer tools to get make and several other GNU tools (see relavent section of this article). If you are not on Mac, we recommend installing it via a package manager, e.g.

  • brew install make on Mac

  • apt-get install make on Linux

  • choco install make on Windows