Query about GAMSPy academic license

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?

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

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.