MESSAGEix requires GAMS.
Run the installer.
Ensure that the
PATHenvironment variable on your system includes the path to the GAMS program:
on Windows, in the GAMS installer…
Check the box labeled “Use advanced installation mode.”
Check the box labeled “Add GAMS directory to PATH environment variable” on the Advanced Options page.
on other platforms (macOS or Linux), add the following line to a file such as
MESSAGE-MACRO and MACRO require GAMS 24.8.1 or later (see
The latest version is recommended.
GAMS is proprietary software and requires a license to solve optimization problems.
To run both the
ixmp tutorials and test suites, a “free demonstration” license is required; the free license is suitable for these small models.
Versions of GAMS up to version 29 include such a license with the installer; since version 30, the free demo license is no longer included, but may be requested via the GAMS website.
If you only have a license for an older version of GAMS, install both the older and the latest versions.
reporting.Reporter.visualize() uses Graphviz, a program for graph visualization.
Installing message_ix causes the python
graphviz package to be installed.
If you want to use
visualize() or run the test suite, the Graphviz program itself must also be installed; otherwise it is optional.
If you Install MESSAGEix via Anaconda, Graphviz is installed automatically via its conda-forge package. For other methods of installation, see the Graphviz download page for downloads and instructions for your system.
After installing GAMS, we recommend that new users install Anaconda, and then use it to install MESSAGEix. Advanced users may choose to install MESSAGEix from source code (next section).
Install Python via Anaconda. We recommend the latest version; currently Python 3.8.
Open a command prompt. We recommend Windows users use the “Anaconda Prompt” to avoid permissions issues when installing and using MESSAGEix. This program is available in the Windows Start menu after installing Anaconda.
$ conda install -c conda-forge message-ix
Install ixmp from source.
(Optional) If you intend to contribute changes to MESSAGEix, first register a Github account, and fork the message_ix repository. This will create a new repository
<user>/message_ix. (Please also see Contributing to MESSAGEix development.)
Clone either the main repository, or your fork; using the Github Desktop client, or the command line:
$ git clone email@example.com:iiasa/message_ix.git # or: $ git clone firstname.lastname@example.org:USER/message_ix.git
Open a command prompt in the
message_ixdirectory and type:
$ pip install --editable .[docs,reporting,tests,tutorial]
--editableflag ensures that changes to the source code are picked up every time
import message_ixis used in Python code. The
[docs,reporting,tests,tutorial]extra dependencies ensure additional dependencies are installed.
(Optional) If you will be using
MESSAGE_master.gmsoutside of Python
message_ixto run MESSAGEix, you will likely modify this file, but will not want to commit these changes to Git. Set the Git “assume unchanged” bit for this file:
$ git update-index --assume-unchanged message_ix/model/MESSAGE_master.gms
To unset the bit, use
--no-assume-unchanged. See the Git documentation for more details.
(Optional) Run the built-in test suite to check that MESSAGEix functions correctly on your system:
By default, the GAMS files containing the mathematical model core are installed
message_ix (e.g., in your Python
site-packages directory). Many
users will simply want to run MESSAGEix, or use the Python or R APIs to
manipulate data, parameters and scenarios. For these uses, direct editing of the
GAMS files is not necessary.
To edit the files directly—to change the mathematical formulation, such as adding new types of parameters, constraints, etc.—use the
message-ix command-line program to copy the model files in a directory of your choice:
$ message-ix copy-model /path/for/model/files
You can also set the
message model dir configuration key so that this copy of the files is used by default:
$ message-ix config set "message model dir" /path/for/model/files
…or do both in one step:
$ message-ix copy-model --set-default /path/for/model/files