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Using NEOS

You can submit your model to be solved at NEOS via the neos terminal command. Use the command line helper graphical interface to execute a neos command:

Alternatively, type your command directly into the terminal. Checkout out our NEOS usage examples.

Limitations of NEOS and of the neos command

NEOS doesn't know your project structure

File reading commands such as data in AMPL and $include in GAMS are pretty much useless in NEOS. There are two main reasons for that:

• In each neos execution, only the files that are specified in the command line are sent to NEOS.
• The files that you submit to NEOS are renamed internally, so you will not be able to refer to them with their original names.

Therefore, unless you are refering to files that you create dynamically, during the execution of your program, you should avoid using file reading commands.

Interpreters run in restricted modes

• AMPL is executed with the -R command line option, which puts AMPL in 'server mode'. In this mode, it declines to execute cd and shell commands, forbids changes to options TMPDIR, ampl_include, and PATH (or the search path for the operating system being used), disallows pipe functions, and restricts names in option solver and file redirections to be alphanumeric (so they can only write to the current directory, which, on Unix systems at least, cannot be changed).
• GAMS is executed with the command line option -execmode=3, which sets the restriction level to 3. In this level, embedded code and all $call and execute commands are prohibited, and $echo and put commands can only write to directories in or below the working or scratchdir.

Time and memory limits

By default, your jobs will run for at most 5 minutes. If you need more time, use the --priority long command line option, which will allow your job to run for at most 8 hours. However, the output of long jobs can only be seen after completion. Additionally, every job submitted to the NEOS Server is limited to 3 GB of RAM. Learn more at the NEOS FAQ.

Unsupported files

There is no way to submit any kind of binary file to NEOS, which means that .xls and .xlsx files are not supported. Additionally, NEOS will not accept input files larger than 16 MB.

List of available solvers

Use the -s <solver_name> command line option to select one of the solvers below:

• NEOS FAQ
• Running a Solver
• Terminal Commands