GAMS

GAMSShell Solver

GAMSShell.available([exception_flag]) True if the solver is available.
GAMSShell.executable() Returns the executable used by this solver.
GAMSShell.solve(*args, **kwds) Solve a model via the GAMS executable.
GAMSShell.version() Returns a 4-tuple describing the solver executable version.
GAMSShell.warm_start_capable() True is the solver can accept a warm-start solution.
class pyomo.solvers.plugins.solvers.GAMS.GAMSShell(**kwds)[source]

A generic shell interface to GAMS solvers.

available(exception_flag=True)[source]

True if the solver is available.

executable()[source]

Returns the executable used by this solver.

solve(*args, **kwds)[source]

Solve a model via the GAMS executable.

Keyword Arguments:
 
  • tee=False (bool) – Output GAMS log to stdout.
  • logfile=None (str) – Filename to output GAMS log to a file.
  • load_solutions=True (bool) – Load solution into model. If False, the results object will contain the solution data.
  • keepfiles=False (bool) – Keep temporary files.
  • tmpdir=None (str) – Specify directory path for storing temporary files. A directory will be created if one of this name doesn’t exist. By default uses the system default temporary path.
  • report_timing=False (bool) – Print timing reports for presolve, solver, postsolve, etc.
  • io_options (dict) – Options that get passed to the writer. See writer in pyomo.repn.plugins.gams_writer for details. Updated with any other keywords passed to solve method. Note: put_results is not available for modification on GAMSShell solver.

GAMSDirect Solver

GAMSDirect.available([exception_flag]) True if the solver is available.
GAMSDirect.solve(*args, **kwds) Solve a model via the GAMS Python API.
GAMSDirect.version() Returns a 4-tuple describing the solver executable version.
GAMSDirect.warm_start_capable() True is the solver can accept a warm-start solution.
class pyomo.solvers.plugins.solvers.GAMS.GAMSDirect(**kwds)[source]

A generic python interface to GAMS solvers.

Visit Python API page on gams.com for installation help.

available(exception_flag=True)[source]

True if the solver is available.

solve(*args, **kwds)[source]

Solve a model via the GAMS Python API.

Keyword Arguments:
 
  • tee=False (bool) – Output GAMS log to stdout.
  • logfile=None (str) – Filename to output GAMS log to a file.
  • load_solutions=True (bool) – Load solution into model. If False, the results object will contain the solution data.
  • keepfiles=False (bool) – Keep temporary files. Equivalent of DebugLevel.KeepFiles. Summary of temp files can be found in _gams_py_gjo0.pf
  • tmpdir=None (str) – Specify directory path for storing temporary files. A directory will be created if one of this name doesn’t exist. By default uses the system default temporary path.
  • report_timing=False (bool) – Print timing reports for presolve, solver, postsolve, etc.
  • io_options (dict) – Options that get passed to the writer. See writer in pyomo.repn.plugins.gams_writer for details. Updated with any other keywords passed to solve method.

GAMS Writer

This class is most commonly accessed and called upon via model.write(“filename.gms”, …), but is also utilized by the GAMS solver interfaces.

class pyomo.repn.plugins.gams_writer.ProblemWriter_gams[source]
__call__(model, output_filename, solver_capability, io_options)[source]

Write a model in the GAMS modeling language format.

Keyword Arguments:
 
  • output_filename (str) – Name of file to write GAMS model to. Optionally pass a file-like stream and the model will be written to that instead.
  • io_options (dict) –
    • warmstart=True
      Warmstart by initializing model’s variables to their values.
    • symbolic_solver_labels=False
      Use full Pyomo component names rather than shortened symbols (slower, but useful for debugging).
    • labeler=None
      Custom labeler. Incompatible with symbolic_solver_labels.
    • solver=None
      If None, GAMS will use default solver for model type.
    • mtype=None
      Model type. If None, will chose from lp, nlp, mip, and minlp.
    • add_options=None
      List of additional lines to write directly into model file before the solve statement. For model attributes, <model name> is GAMS_MODEL.
    • skip_trivial_constraints=False
      Skip writing constraints whose body section is fixed.
    • file_determinism=1
      How much effort do we want to put into ensuring the
      GAMS file is written deterministically for a Pyomo model:
      0 : None
      1 : sort keys of indexed components (default)
      2 : sort keys AND sort names (over declaration order)
    • put_results=None
      Filename for optionally writing solution values and marginals to (put_results).dat, and solver statuses to (put_results + ‘stat’).dat.