Remove writer doc from solvers, add writer to sphinx

doc/OnlineDocs/library_reference/solvers/gams.rst

@@ -3,8 +3,8 @@ GAMS
 
 .. currentmodule:: pyomo.solvers.plugins.solvers.GAMS
 
-GAMSShell
----------
+GAMSShell Solver
+----------------
 
 .. autosummary::
 
@@ -17,8 +17,8 @@ GAMSShell
 .. autoclass:: GAMSShell
    :members:
 
-GAMSDirect
-----------
+GAMSDirect Solver
+-----------------
 
 .. autosummary::
 
@@ -29,3 +29,15 @@ GAMSDirect
 
 .. autoclass:: GAMSDirect
    :members:
+
+.. currentmodule:: pyomo.repn.plugins.gams_writer
+
+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.
+
+.. autoclass:: ProblemWriter_gams
+   :members: __call__

pyomo/repn/plugins/gams_writer.py

@@ -133,34 +133,38 @@ def __call__(self,
                  solver_capability,
                  io_options):
         """
-        output_filename:
+        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:
-            warmstart=True:
+        io_options: dict
+            - warmstart=True
                 Warmstart by initializing model's variables to their values.
-            symbolic_solver_labels=False:
+            - symbolic_solver_labels=False
                 Use full Pyomo component names rather than
                 shortened symbols (slower, but useful for debugging).
-            labeler=None:
+            - labeler=None
                 Custom labeler. Incompatible with symbolic_solver_labels.
-            solver=None:
+            - solver=None
                 If None, GAMS will use default solver for model type.
-            mtype=None:
+            - mtype=None
                 Model type. If None, will chose from lp, nlp, mip, and minlp.
-            add_options=None:
+            - 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:
+            - 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.

pyomo/solvers/plugins/solvers/GAMS.py

@@ -153,36 +153,8 @@ def solve(self, *args, **kwds):
         report_timing=False: bool
             Print timing reports for presolve, solver, postsolve, etc.
         io_options: dict
-            Options that get passed to the writer.
+            Options that get passed to the writer. See writer for details.
             Updated with any other keywords passed to solve method.
-
-            - warmstart=False
-                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='results'
-                Filename for optionally writing solution values and
-                marginals to (put_results).dat, and solver statuses
-                to (put_results + 'stat').dat.
         """
 
         # Make sure available() doesn't crash
@@ -640,34 +612,10 @@ def solve(self, *args, **kwds):
         report_timing=False: bool
             Print timing reports for presolve, solver, postsolve, etc.
         io_options: dict
-            Options that get passed to the writer.
+            Options that get passed to the writer. See writer for details.
             Updated with any other keywords passed to solve method.
-
-            - warmstart=False
-                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='results'
-                Not available for modification on GAMSShell solver.
+            Note: put_results is not available for modification on
+            GAMSShell solver.
         """
 
         # Make sure available() doesn't crash