Email Interface

The NEOS Server accepts job submitted via email to The job must be provided in the XML format required by the solver either in the body of the email or as a plain text attachment. To illustrate the process, we show the steps for submitting a GAMS model of a nonlinearly constrained chemical equilibrium optimization problem to the solver KNITRO. The file ChemEq.txt contains the GAMS model of the problem.

Step 1: Select a solver
Go to the list of available solvers by category to select an appropriate solver for your optimization problem.

Step 2: Select the input format
Next to the name of each solver is the list of input types available for the solver; each input type links to a page that contains specific information for the solver-input type combination. Depending on the solver, the input types may be modeling languages (e.g., AMPL, GAMS), programming languages (e.g., C, Fortran) or a solver- or a problem-specific input type (e.g., TSPLIB for TSP, SDPA for semidefinite programming).

For KNITRO, the input types are AMPL and GAMS; when we click on the GAMS link, we are redirected to the information page for KNITRO-GAMS.

Step 3: Prepare the XML format
In the box in the upper right corner (labeled NEOS Interfaces to KNITRO), click on the Email link to view the XML template. The XML template for KNITRO-GAMS is shown below.

The contents of the ChemEq.txt file need to be copied and pasted into the section with the <model> tags and the <wantlog> section needs to specify "yes". The XML version of the file is available here.

Step 4: Submit the job
Compose an email addressed to with the contents of the XML file (e.g. ChemEq-xml.txt) copied and pasted into the body of the message OR with the XML file attached in plain text format. Shortly after you send the email, you should receive a confirmation email with the job number and the password. The email also may include the list of jobs running and queued.
NEOS has received and assigned your submission as job #3079882, password 'SXqtnCsj'

If you do not receive a confirmation email, see the NEOS Server FAQ Why hasn't the server responded to my emailed job yet? for troubleshooting suggestions.

Step 5: Receive the results
If you submitted the job from a valid email address, the results will be sent to you when the job is completed. Alternatively, you can use the job number and password to view the job queue and the job results on the NEOS job admin page. Note that jobs submitted to NEOS are limited to 8 hours of CPU time and at most 3 GB of memory. If you don't receive any results (but you received an initial confirmation email that the NEOS Server received the job), it may be that the job exceeded one of the limits. See the NEOS Server FAQ I submitted a job to NEOS but I never received the results. for more information.