Installation Notes for Windows

# Installation

1. Run windows_x64_64.exe (Windows 64bit): This file is available from https://www.gams.com/latest. Please note that the installation may require administrative privileges on your machine.

You have two options to run the installer: In default or advanced mode. In the default mode, the installer will prompt you for the name of the directory in which to install GAMS. We call this directory the GAMS directory. You may accept the default choice or pick another directory. Please remember: if you want to install two different versions of GAMS, they must be in separate directories.

If you choose to use the advanced mode, the installer will also ask you for a name of a start menu folder, if GAMS should be installed for all users, if the GAMS directory should be added to the PATH environment variable and which desktop icons should be created.

The GAMS License page allows to select a GAMS license. The installer tries to find GAMS licenses in different locations and automatically selects a license to be used with the following precedence:

• Clipboard
• C:\Users\username\Documents\GAMS
• Previous GAMS installation found from the registry (User)
• Previous GAMS installation found from the registry (System)

In addition it is possible to browse for a license file (gamslice.txt) or to skip all license related actions (No License) and install one after the installation process. Note that the use of GAMS requires a license. A free demo license can be requested at https://www.gams.com/download. A license file is written to C:\Users\username\Documents\GAMS when installing for Current User (default). Installing for All Users or checking Write License to System Directory will write the license to the GAMS system directory instead.

For automating the installation of GAMS, it is possible to provide the command line parameters /SP- /SILENT. This will install GAMS in a non-interactive manner using default settings. Note that depending on the security settings, the User Account Control asking for permission might still be active. The following command line parameters are available to further customize the non-interactive installation:

• /allUsers=yes|no (default:no): Can be used in order to install for All Users instead of Current User.
• /noLicense=yes|no (default:no): Can be used in order to prevent any GAMS license from being written.
• /noIcons can be used in order to check the Don't create a Start Menu folder checkbox on the Select Start Menu Folder page.
• /desktopIcons=yes|no (default:yes) can be used in order to turn on/off the creation of Desktop icons.
Attention
Under Windows 10 the Windows Installer package may not update system environment variables (see Microsoft Support). To work around this issue, log off of Windows after the installation, and then log on again.
2. During the installation of GAMS, the setup process helps in setting up the license to be used with GAMS. In case no license has been selected during this process it is required to set this up manually. The license file is nowadays sent via email, with instructions. You can also request a demo license from https://www.gams.com/download. If you don't have a license file yet, choose No license when asked for the GAMS license options. You can install a license later by either manually creating the license file gamslice.txt in a directory GAMS searches to find a license or use the corresponding GAMS Studio dialog.

GAMS searches a couple of system wide and user specific standard locations for a license file.

3. Choose the default solvers: Run GAMS Studio by double clicking studio.exe from the GAMS system subdirectory Studio. To view or edit the default solvers, open the GAMS Configuration Editor in Studio. You can also skip this and thus accept the existing defaults if you wish, but most users want to select new default solvers for each model type.
4. Run a few models to test the GAMS system: The Model Library Explorer allows you to pick some models from the GAMS model library easily. After selecting one, press F9 to run it, and view the solution. To test your installation, run the following models from the GAMS model library:
LP:    trnsport (objective value:  153.675)
NLP:   chenery  (objective value:  1058.9)
MIP:   bid      (optimal solution: 15210109.512)
MINLP: procsel  (optimal solution: 1.9231)
MCP:   scarfmcp (no objective function)
MPSGE: scarfmge (no objective function)


# Visual C++ Redistributable Dependency

• Some solvers in the system as well as GAMS Studio have dependencies on certain Visual C++ libraries. These are present on most Windows systems but are missing on some. If you get a complaint about missing libraries on startup of GAMS Studio or when solving a model, please run the installer vcredist_x64.exe for these libraries, which can be found in the GAMS installation folder in directory [GAMS system]\apifiles\C++\lib\vs2017.

# Command Line Use of GAMS

Users wishing to use GAMS from the command line (aka the console mode) may want to perform the following steps. These steps are not necessary to run GAMS via Studio.

1. We recommend to add the GAMS directory to your environment path in order to avoid having to type in an absolute path name each time you run GAMS. Run the installer in advanced mode and mark the check-box Add GAMS directory to PATH environment variable.
2. Run the program gamsinst: gamsinst is a command line program used to configure GAMS. It prompts the user for default solvers to be used for each model type. If possible, choose solvers you have licensed, since unlicensed solvers will only run in demonstration mode. The solver defaults can be changed by:

a. rerunning gamsinst and resetting the default values

b. setting a command line default, e.g. gams trnsport lp=bdmlp

c. by an option statement in the GAMS model, e.g: option lp=bdmlp;

The system wide solver defaults are shared by the command line and GAMS Studio, so you can also choose to set these defaults using GAMS Studio.