Without a valid GAMS license the system will not run and produces the following output:
*** No license specified and no gamslice.txt found in standard locations.
NOTE: You can find more general information on licenses in the standard price list and the academic price list.
A free demo license time-limited for 5 months is included with the GAMS distribution. The demo license lets you generate and solve small models, see also Additional Limits for the Demo and Community License . On expiration you need to update your GAMS system, which then comes with a new demo license, or buy a professional license. Demo licenses require a recent GAMS version, not older than 18 months.
GAMS will terminate with an error message, if it hits one of the limits above:
*** Status: Terminated due to a licensing error
*** Inspect listing file for more information
Users can request a free community license from community@gams.com . The community license lets you generate and solve linear models (LP, MIP, and RMIP) that do not exceed 5000 variables and 5000 constraints. For all other model types the model cannot be larger than 2500 variables and 2500 constraints. Restrictions you experience with the demo license, i.e. additional limits enforced by some solvers, time-limitation of 12 months, and a recent GAMS system also apply to the community license. The free demo and community license cannot be combined with a professional license. They are for demonstration and evaluation but not for commercial and production work.
Non-academic customers can request time-limited evaluation licenses for testing GAMS under real-world conditions. These licenses come with no functional restrictions, allowing users to utilize GAMS for up to 30 days free of charge. With an evaluation license, users can try different solvers before making a purchase decision, ensuring they find the best fit for their needs. Note that these evaluation licenses are not for commercial and production work.
Usage beyond the free demo and community license requires a license for the GAMS Base Module and for most of the GAMS/Solvers and the GAMS/Solver-Links:
We distinguish between academic and commercial licenses. Academic licenses can only be used for teaching and research at degree granting institutions. Moreover, we distinguish between time-limited and perpetual licenses. For perpetual licenses the first year of maintenance, support and updates is included in the initial purchase of the software. Maintained licenses qualify for free updates, adding components, platform-switching without additional charge, and multi-copy discounts on the same platform. After the first year maintenance can be extended by paying a fee. Licenses are typically limited to a single computer platform type (e.g. Windows or Linux), but there are also licenses available, which will work on all major platforms supported by GAMS. Free academic licenses are available for certain solvers. Please see here for further information about the pricing of an appropriate license.
A GAMS license is an ASCII file of six lines. Please copy all six lines into a new file named gamslice.txt and place this into a location searched by GAMS. Details can be found in the installation notes of the specific operating system:
Before installing a new GAMS version, please check whether it will work with your current GAMS license. The Check for Update functionality of GAMS Studio can be used to see if a newer GAMS version is available and what the newest version is that can be used with a given license.
Below is a sample output for a license, which is still under maintenance:
*** Processing GAMS system directory C:\gams\win64\24.8
*** Reading license file C:\ProgramData\GAMS\gamslice.txt
*** Your system is up to date
If your license is no longer under maintenance, you will receive a message like the one below:
*** Processing GAMS system directory C:\GAMS\win64\23.9
*** Reading license file C:\ProgramData\GAMS\gamslice.txt
*** Your license is 1276 days too old to run with the most recent system
*** The version of your GAMS system is 23.9.5
*** The last GAMS version you can use is 24.1.3
*** Please request the download of an older version from sales@gams.com
*** For ordering an update to use the most recent version (24.8.5)
*** please contact your distributor
Errors or warnings triggered by a problem with the GAMS license file (gamslice.txt) are reported both in the log file and in the listing file. Below are some typical error and warning messages and instructions on how to overcome them.
Without a license file GAMS will not work. If you have received a license file (gamslice.txt), follow the instructions from the previous section. Do not try to rename it or to modify the contents of the license file. Without a license GAMS will give you an error message like the one below:
*** No license specified and no gamslice.txt found in standard locations.
Running GAMS with an invalid license will give you an error message like the one below:
*** License File validation failed
Do not try to modify your license file, any change will break it. If the original license file is no longer available, please contact sales@gams.com and ask for a copy of your license file. Please attach the license file you are currently using. This error also pops up, if you are using a license file, which was issued for a different platform.
If are trying to run an old license file with a newer GAMS distribution, you may get an error message stating:
*** License file too old for this version of GAMS.
*** Maintenance expired 2840 days ago.
*** More than 60 days since expiration, sorry...
*** Run an older GAMS system or renew the license
Replace that GAMS system with the one you got together with your license file (use the “Check for Update” utility mentioned above to find out the latest version you can use with the current license; old systems are available on request from sales@gams.com ) or update your license to the current version.
If one of the solvers you are trying to use (or is selected as the default solver) is not included in your license file and the size of the model exceed the limits of the free demo or community version, you will get an error stating:
*** No license found
*** To update your license, please contact your distributor.
Check whether the default solvers for a particular problem class are included in the license. Please note that some of the solvers call other solvers as a sub-solver, e.g.:
The complete message is:
*** License file too old for this version of GAMS.
*** Maintenance expired xx days ago.
If GAMS continues working, you can ignore this warning. However, any forthcoming GAMS distribution will most likely not work, but downgrade to the limits of the free demo system.
This warning (without further error messages) indicates that the time limited license (e.g. an evaluation license) will stop working soon.
The model size limits enforced by GAMS are:
In addition to the GAMS model size limits, the solvers might impose stricter limits when running with a demo or community license. We use m for the number constraints, n for the number variables, nd for the number of discrete variables, nz for the number nonzeros, and nlnz for the number nonlinear nonzeros:
The demo license of MIRO connector allows up to 10 indexed input and output symbols.