In case you think GAMS or the solver fails, please provide us with as much relevant information as possible, such as:

• Your operating system
• GAMS version and solver used
• Size and structure (linear, nonlinear etc.) of the model

Most of these information are included in the log file (.log):

• If you are using the GAMSIDE, there will be a file called model_name.log in your GAMS project directory. Alternatively you may just copy and paste the content of the process window into an e-mail.
• If you are working from the command line, please use the additional command line option lo=2 (e.g. gams trnsport.gms lo=2) to redirect the screen output into a log file.

Find below an example of a log file (trnsport.log):

--- Job trnsport.gms Start 08/10/15 11:44:37 24.4.6 r52563 WEX-WEI x86 64bit/MS Windows
GAMS 24.4.6   Copyright (C) 1987-2015 GAMS Development. All rights reserved
Licensee: Franz Nelissen                                 S150318/0001CN-GEN
          GAMS Software GmbH                                         DC3459
--- Starting compilation
--- trnsport.gms(69) 3 Mb
--- Starting execution: elapsed 0:00:00.002
--- trnsport.gms(45) 4 Mb
--- Generating LP model transport
--- trnsport.gms(66) 4 Mb
---   6 rows  7 columns  19 non-zeroes
....

Please send us that file.

If possible also attach a (zipped) copy of your model and all necessary data files, which will allow us to reproduce the problem. In case there are confidential issues, you may send us a scalar version of your model, click here for instructions about that.

Our e-mail system can handle attachments up to a size of 15MB. If you have to send us larger files please use our file upload facility and send us the name of the uploaded file.

As a security measure to prevent potential viruses, our mail system does not accept executable files (such as files ending in .exe, bat, or cmd), even if they are sent in a zipped (.zip, .tar, .tgz, .taz, .z, .gz) format. Any message of this type sent to us will be bounced back you. Adding an underscore to the file attachment (e.g. file.zip_) will help.

Please also visit our Support Wiki.

You can reach GAMS by several means of communication: mail, fax and phone. The full addresses are:

1. GAMS Development Corporation, USA
   • Phone: (+1) 202 342-0180
   • support@gams.com
2. GAMS Software GmbH, Germany
   • Phone: (+49) 221 949-9170
   • support@gams.com