New GAMS solver interface, writer, and solution loader. #3683

AnhTran01 · 2025-08-07T18:07:31Z

Fixes NA

Summary/Motivation:

This PR introduced a new GAMS solver interface that uses the LinearRepnVisitor to enable coefficient gathering when writing out the scalar GAMS model in gms format.

Changes proposed in this PR:

New GAMS solver interface in pyomo.contrib.solver.solvers
New GAMS writer in pyomo.repn.plugins
New GAMS solution loader in pyomo.contrib.solver.solvers

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

I agree my contributions are submitted under the BSD license.
I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

…ittest and coverage test

AnhTran01 · 2025-08-07T18:07:57Z

@boxblox
@abhosekar

mrmundt · 2025-08-07T18:11:30Z

@AnhTran01 - Please make sure to run black on your changes!

mrmundt

Immediate piece of feedback, recognizing that I have not thoroughly looked over anything - there are no tests anywhere, and there absolutely will need to be some.

Thanks for this, though, I am so excited!!

…riting process. Added WIP unittest for the new solver interface

…ion error

… and writing to gms.

pyomo/repn/plugins/gams_writer_v2.py

… constraint). Fixed bug of load_solution that contains constraint id in addition to variable id

…e_gdx_results

…arsing solver_options

jsiirola

(Some initial comments, mostly on configuration)

pyomo/contrib/solver/solvers/gams.py

jsiirola · 2025-08-15T21:42:22Z

pyomo/contrib/solver/solvers/gams.py

+        if config.logfile is not None:
+            config.logfile = os.path.abspath(config.logfile)
+
+        config.writer_config.put_results_format = 'gdx' if gdxcc_available else 'dat'


This should probably only overwrite the configuration if it is still None (that way users can set / override the interface)

…lable() and version()

…are no longer valid.

pyomo/contrib/solver/solvers/gams.py

pyomo/repn/plugins/gams_writer_v2.py

pyomo/contrib/solver/solvers/gms_sol_reader.py

blnicho · 2025-11-18T20:03:46Z

@AnhTran01 did you see the review comments from @mrmundt? Are you going to have a chance to work on this in the near future?

AnhTran01 · 2025-11-18T20:08:34Z

@blnicho I've seen the comments and they're part of my todo. I'm aiming to implement these by Nov. 30th.

…bounds - default to large number

…fied handling log_level conditional.

…ib.solver.common.util

…rsion. Added helper function for _simple_model and _run_simple_model

…write_path_win8p3

… -INF when None is provided

…nd _run_simple_model

Co-authored-by: Miranda Mundt <55767766+mrmundt@users.noreply.github.com>

Added new GAMS solver interface, writer, and solution loader. WIP: un…

1177492

…ittest and coverage test

Norman_Tran and others added 2 commits August 7, 2025 14:14

Ran black -S -C on commited files

2385654

Typo!

b36086f

mrmundt requested changes Aug 7, 2025

View reviewed changes

Norman_Tran and others added 14 commits August 7, 2025 17:02

Added ignore checking for constant in the objective function during w…

e91e480

…riting process. Added WIP unittest for the new solver interface

Added support for add_options for multiple solver_options

b060096

typo

96ba646

ran black formatter

b0f16a3

added add_options in the solver_interface

dde656c

Fixed bug with unable to create tmpdir. Updated test_gams_v2.py

3476f72

Merge branch 'main' into GAMS_new_solver_interface

ddfd98c

Added handling single bounded variable case (None,#) or (#, None)

eb0a3db

Match solver interface and writer configs to prevent implicit definit…

c6d2d01

…ion error

Added new gams solver interface for test_all_solvers_list()

2a6dcb7

Fixed bug of handling valid ub when writing pyomo expression

b6ead27

Fixed bug when using ComponentMap to extract duals in gms_sol_reader.py

89f80e0

Corrected handling of solution_loader. Implemented bounded constraint…

b0c3450

… and writing to gms.

Added offdigit based on error log message suggestion

a9df1d7

boxblox reviewed Aug 14, 2025

View reviewed changes

pyomo/repn/plugins/gams_writer_v2.py Show resolved Hide resolved

mrmundt and others added 4 commits August 15, 2025 07:47

Merge branch 'main' into GAMS_new_solver_interface

e04c89f

Fixed bug of extracting constraint dual when alias exits (for bounded…

518758e

… constraint). Fixed bug of load_solution that contains constraint id in addition to variable id

Added aliases as part of parse_dat_results to be consistent with pars…

a2ef9cc

…e_gdx_results

Removed code duplication between the solver interface and writer by p…

c33095d

…arsing solver_options

jsiirola reviewed Aug 18, 2025

View reviewed changes

Norman_Tran and others added 4 commits August 19, 2025 14:31

Revised code based on John's review. WIP: Handling rehash within avai…

f609ca2

…lable() and version()

Re-added config into available and version, and deprecated test that …

ec5aa6a

…are no longer valid.

Merge branch 'main' into GAMS_new_solver_interface

e760a1c

Sanity check config.writer_config.put_results_format without setdefault

7bb817b

mrmundt requested changes Sep 9, 2025

View reviewed changes

blnicho added this to Pyomo 6.10 Nov 11, 2025

github-project-automation bot moved this to Todo in Pyomo 6.10 Nov 11, 2025

blnicho moved this from Todo to Review In Progress in Pyomo 6.10 Nov 11, 2025

Norman_Tran and others added 18 commits January 6, 2026 09:47

Corrected typos and added handling case for integer variable without …

58362af

…bounds - default to large number

Removed duplicate config within solver and writer (row_order). Simpli…

94396a9

…fied handling log_level conditional.

Removed duplicate error message string that is handled by pyomo.contr…

6243b06

…ib.solver.common.util

Renamed to test_gams.py and added cache unittest for available and ve…

afa0ef0

…rsion. Added helper function for _simple_model and _run_simple_model

Removed deprecated functions (_simple_model / _run_simple_model / _re…

a723a06

…write_path_win8p3

Updated the handling of bounds for integer variables by using INF and…

bf8db4f

… -INF when None is provided

Added document_class_CONFIG to remove redundant documentation

71a35e8

Additional documentation cleanup

d619cb3

Updated test_gams.py comments for standalone function _simple_model a…

437a03a

…nd _run_simple_model

Moved gams_results in postsolve into results.extra_info

f1b9b03

Merge branch 'main' into GAMS_new_solver_interface

c677f71

ran black formatter

f845c0c

Merge branch 'main' into GAMS_new_solver_interface

c44577d

fixup of writing bounds

a92d26b

Merge branch 'main' into GAMS_new_solver_interface

bc8bca3

black 26.1.0 formatting

8ebf3a0

Added results.solver_config in gams.py:solve

2f13aeb

keep solver_log in results object

0f4cba1

boxblox mentioned this pull request Jan 21, 2026

Add flexibility into error message checking on gurobi_minlp #3822

Merged

boxblox and others added 5 commits January 21, 2026 16:19

Merge branch 'main' into GAMS_new_solver_interface

225744d

Apply suggestion from @mrmundt

3c504ea

Co-authored-by: Miranda Mundt <55767766+mrmundt@users.noreply.github.com>

Apply suggestion from @mrmundt

331a367

Co-authored-by: Miranda Mundt <55767766+mrmundt@users.noreply.github.com>

fixups

0e0c637

Merge branch 'main' into GAMS_new_solver_interface

08c63e7

New GAMS solver interface, writer, and solution loader. #3683

Are you sure you want to change the base?

New GAMS solver interface, writer, and solution loader. #3683

Conversation

AnhTran01 commented Aug 7, 2025

Fixes NA

Summary/Motivation:

Changes proposed in this PR:

Legal Acknowledgement

Uh oh!

AnhTran01 commented Aug 7, 2025

Uh oh!

mrmundt commented Aug 7, 2025

Uh oh!

mrmundt left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

jsiirola left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

jsiirola Aug 15, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

blnicho commented Nov 18, 2025

Uh oh!

AnhTran01 commented Nov 18, 2025

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants