Query about GAMSPy academic license

GAMSPy
1

My understanding of the GAMSPy academic license was that it provided unlimited access to commercial solvers. But I’m getting the following error with my model:

--- Job _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms Start 09/27/24 09:08:02 47.6.0 c2de9d6d DAX-DAC arm 64bit/macOS
--- Applying:
    /Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy_base/gmsprmun.txt
--- GAMS Parameters defined
    NLP conopt
    Input /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/_73b3898f-bb42-4e4a-9294-cfdc5e713404.gms
    Output /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/_73b3898f-bb42-4e4a-9294-cfdc5e713404.lst
    ScrDir /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/tmpu3rj4v_m/
    SysDir /Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy_base/
    LogOption 3
    Trace /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/_73b3898f-bb42-4e4a-9294-cfdc5e713404.txt
    License /Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy_base/user_license.txt
    OptFile 1
    OptDir /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/
    LimRow 0
    LimCol 0
    TraceOpt 3
    GDX /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/_73b3898f-bb42-4e4a-9294-cfdc5e713404out.gdx
    SolPrint 0
    PreviousWork 1
    gdxSymbols newOrChanged
Licensee: Simon Moulds                                   G240913+0003Ac-GEN
          simon.moulds@ed.ac.uk                                   GPA100377
          /Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy_base/user_license.txt
          node:40393001                                                    
          Time-limited free academic license
          The evaluation period of the license will expire on Sep 08, 2025
Processor information: 1 socket(s), 12 core(s), and 12 thread(s) available
--- Starting compilation
--- _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms(67) 5 Mb
--- Starting execution: elapsed 0:00:00.012
--- Generating NLP model mymod
--- _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms(103) 8 Mb
---   255 rows  4,894 columns  14,680 non-zeroes
---   48,935 nl-code  4,893 nl-non-zeroes
--- Range statistics (absolute non-zero finite values)
--- RHS       [min, max] : [ 1.135E-01, 2.535E+05] - Zero values observed as well
--- Bound     [min, max] : [ 1.000E-06, 1.000E-06]
--- Matrix    [min, max] : [ 1.016E-20, 4.630E+03] - Zero values observed as well
--- _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms(103) 6 Mb
--- Executing CONOPT (Solvelink=2): elapsed 0:00:00.025

CONOPT 4         47.6.0 c2de9d6d Sep 12, 2024          DAC arm 64bit/macOS    

*** No license found
*** To update your license, please contact your distributor.
*** LICENSE ERROR: (see above)
*** Contact support@gams.com for help.
--- Reading solution for model mymod
--- Executing after solve: elapsed 0:00:00.057
--- _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms(165) 6 Mb
--- GDX File /var/folders/7k/qtrfjf450td_j671mcj999bc0000gn/T/tmpaku0c5xt/_73b3898f-bb42-4e4a-9294-cfdc5e713404out.gdx
*** Status: Normal completion
--- Job _73b3898f-bb42-4e4a-9294-cfdc5e713404.gms Stop 09/27/24 09:08:02 elapsed 0:00:00.059
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy/_model.py", line 1143, in solve
    summary = runner.run()
              ^^^^^^^^^^^^
  File "/Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy/_backend/local.py", line 91, in run
    self.execute_gams(gams_string)
  File "/Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy/_backend/local.py", line 124, in execute_gams
    raise exception
  File "/Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy/_backend/local.py", line 114, in execute_gams
    self.model._update_model_attributes()
  File "/Users/smoulds/mambaforge/envs/gamspy/lib/python3.12/site-packages/gamspy/_model.py", line 887, in _update_model_attributes
    raise GamspyException(
gamspy.exceptions.GamspyException: Solve status: LicenseError. The solver cannot find the appropriate license key needed to use a specific subsolver.

=============
Error Summary
=============

**** SOLVER STATUS     7 Licensing Problems
**** MODEL STATUS      11 Licensing Problem
**** OBJECTIVE VALUE               NA

 RESOURCE USAGE, LIMIT         NA     10000000000.000
 ITERATION COUNT, LIMIT        NA    2147483647
 EVALUATION ERRORS             NA             0
*** No license found

This suggests to me that I’ve hit a size restriction, because with a smaller problem it runs fine. Please could you confirm whether the commercial solvers included with GAMSPy are restricted?

2

The page GAMS Academic Program makes it clear which (commercial) solvers are included in the free GAMSPy academic license:

Commercial Solvers: Integrated licenses for select commercial solvers, including CPLEX, COPT, and MOSEK. Additionally, link-licenses are available for GUROBI and XPRESS.

So for NLP problems, you will need to use IPOPT or IPOPTH (with the HSL linear solver).

-Michael

3

Thanks Michael. It wasn’t clear to me whether the list of included commercial solvers was exhaustive or not. Thanks for the pointer to IPOPT/IPOPTH.