GoKestrel: Kestrel AMPL client for all platforms

This project replicates https://github.com/NEOS-Server/Kestrel-AMPL-Linux/ in Go in order to produce binaries that can be easily distributed for various platforms without requiring Python to be installed.

Protocol: NEOS XML-RPC protocol

Downlaod from: https://portal.ampl.com/user/ampl/download/list

Usage

Solving directly

ampl: model diet.mod;
ampl: data diet.dat;
ampl: option solver kestrel;
ampl: option email "***@***.***";
ampl: option kestrel_options "solver=cplex";
ampl: option cplex_options "display=2";
ampl: solve;
Connecting to: neos-server.org:3333
Job XXXX submitted to NEOS, password='xxxx'
Check the following URL for progress report:
https://neos-server.org/neos/cgi-bin/nph-neos-solver.cgi?admin=results&jobnumber=XXXX&pass=xxxx
Job XXXX dispatched
password: xxxx
---------- Begin Solver Output -----------
Condor submit: 'neos.submit'
Condor submit: 'watchdog.submit'
Job submitted to NEOS HTCondor pool.
CPLEX 20.1.0.0: optimal solution; objective 88.2
1 dual simplex iterations (0 in phase I)

Using commands for asyncronous submissions

The command files kestrelsub, kestrelret, and kestrelkill are available at commands/. To insure that AMPL will find the scripts, place them in the directory (or folder) that will be current when you execute AMPL, or set option ampl_include to specify the directory where the script can be found.

$ ampl
ampl: model diet.mod;
ampl: data diet.dat;
ampl: option email "***@***.***";
ampl: option kestrel_options "solver=cplex";
ampl: commands kestrelsub;
Connecting to: neos-server.org:3333
Submitting model at kmodel.nl
Job XXXX submitted to NEOS, password='xxxx'
Check the following URL for progress report:
https://neos-server.org/neos/cgi-bin/nph-neos-solver.cgi?admin=results&jobnumber=XXXX&pass=xxxx
ampl: commands kestrelret;
Connecting to: neos-server.org:3333
Writting solution to kmodel.sol
CPLEX 20.1.0.0: optimal solution; objective 88.2
0 simplex iterations (0 in phase I)
ampl: option kestrel_options 'job=XXXX password=xxxx';
ampl: commands kestrelkill;
Connecting to: neos-server.org:3333
Job XXXX is finished

Using shell for asyncronous submissions

If the folder containing AMPL and all solvers including kestrel is in the environment variable PATH, it may be more convenient to submit/retrieve/kill jobs invoking kestrel directly instead of using commands as follows:

$ ampl
ampl: model diet.mod;
ampl: data diet.dat;
ampl: option ampl_id (_pid); # get a submission queue (first-in-first-out) for this AMPL session
ampl: option email "***@***.***"; # required by NEOS
ampl: option kestrel_options "solver=cplex"; # solver to use on NEOS
ampl: option kestrel_stub "kmodel"; # stub file used by kestrel submit/retrieve
ampl: write bkmodel; # write model to kmodel.nl
ampl: shell "kestrel submit"; # submit the job
Connecting to: neos-server.org:3333
Submitting model at kmodel.nl
Job XXXX submitted to NEOS, password='xxxx'
Check the following URL for progress report:
https://neos-server.org/neos/cgi-bin/nph-neos-solver.cgi?admin=results&jobnumber=XXXX&pass=xxxx
ampl: shell "kestrel retrieve"; # retrieve the job
Connecting to: neos-server.org:3333
Writting solution to kmodel.sol
ampl: solution kmodel.sol; # load the solution
CPLEX 20.1.0.0: optimal solution; objective 88.2
1 dual simplex iterations (0 in phase I)
ampl: shell "kestrel kill XXXX xxxx"; # to kill a job
Connecting to: neos-server.org:3333
Job XXXX is finished

Authenticated submissions

For authenticated submissions set neos_username and neos_user_password as follows:

ampl: option neos_username 'username';
ampl: option neos_user_password 'password';

Priority

Jobs submitted with the priority of long can run for at most 8 hours. Jobs submitted with the priority short can run for at most 5 minutes. Results for long jobs do not stream. You can control the priority as follows:

ampl: option kestrel_options "solver=xxx priority=short";

or

ampl: option kestrel_options "solver=xxx priority=long";

In this driver we set the default priority to short so that we can retrieve output from the solver.

License

BSD-3

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