Make exporting of PyROS subproblems more customizable

doc/OnlineDocs/explanation/solvers/pyros.rst

@@ -906,13 +906,13 @@ Observe that the log contains the following information:
   information, (UTC) time at which the solver was invoked,
   and, if available, information on the local Git branch and
   commit hash.
-* **Summary of solver options** (lines 19--38).
-* **Preprocessing information** (lines 39--41).
+* **Summary of solver options** (lines 19--40).
+* **Preprocessing information** (lines 41--43).
   Wall time required for preprocessing
   the deterministic model and associated components,
   i.e., standardizing model components and adding the decision rule
   variables and equations.
-* **Model component statistics** (lines 42--58).
+* **Model component statistics** (lines 44--61).
   Breakdown of model component statistics.
   Includes components added by PyROS, such as the decision rule variables
   and equations.
@@ -927,7 +927,7 @@ Observe that the log contains the following information:
   The number of truly uncertain parameters detected during preprocessing
   is also noted in parentheses
   (in which "eff." is an abbreviation for "effective").
-* **Iteration log table** (lines 59--69).
+* **Iteration log table** (lines 62--69).
   Summary information on the problem iterates and subproblem outcomes.
   The constituent columns are defined in detail in
   :ref:`the table following the snippet <table-iteration-log-columns>`.
@@ -953,7 +953,7 @@ Observe that the log contains the following information:
 
 * **Termination statistics** (lines 89--94). Summary of statistics related to the
   iterate at which PyROS terminates.
-* **Exit message** (lines 95--96).
+* **Exit message** (lines 95--97).
 
 
 .. _solver-log-snippet:
@@ -963,10 +963,10 @@ Observe that the log contains the following information:
    :linenos:
 
    ==============================================================================
-   PyROS: The Pyomo Robust Optimization Solver, v1.3.8.
+   PyROS: The Pyomo Robust Optimization Solver, v1.3.9.
           Pyomo version: 6.9.3dev0
           Commit hash: unknown
-          Invoked at UTC 2025-05-05T00:00:00.000000+00:00
+          Invoked at UTC 2025-07-21T00:00:00.000000+00:00
 
    Developed by: Natalie M. Isenberg (1), Jason A. F. Sherman (1),
                  John D. Siirola (2), Chrysanthos E. Gounaris (1)
@@ -977,7 +977,7 @@ Observe that the log contains the following information:
    of Energy's Institute for the Design of Advanced Energy Systems (IDAES).
    ==============================================================================
    ================================= DISCLAIMER =================================
-   PyROS is still under development. 
+   PyROS is still under development.
    Please provide feedback and/or report any issues by creating a ticket at
    https://github.com/Pyomo/pyomo/issues/new/choose
    ==============================================================================
@@ -998,6 +998,7 @@ Observe that the log contains the following information:
     backup_local_solvers=[]
     backup_global_solvers=[]
     subproblem_file_directory=None
+    subproblem_format_options={'bar': {'symbolic_solver_labels': True}}
     bypass_local_separation=False
     bypass_global_separation=False
     p_robustness={}
@@ -1025,33 +1026,34 @@ Observe that the log contains the following information:
    ------------------------------------------------------------------------------
    Itn  Objective    1-Stg Shift  2-Stg Shift  #CViol  Max Viol     Wall Time (s)
    ------------------------------------------------------------------------------
-   0     3.5838e+07  -            -            5       1.8832e+04   0.759
-   1     3.5838e+07  2.9329e-09   5.0030e-10   5       2.1295e+04   1.573
-   2     3.6285e+07  7.6526e-01   2.0398e-01   2       2.2457e+02   2.272
-   3     3.6285e+07  7.7212e-13   1.2525e-10   0       7.2940e-08g  5.280
+   0     3.5838e+07  -            -            5       1.8832e+04   0.611
+   1     3.5838e+07  1.2289e-09   1.5886e-12   5       2.8919e+02   1.702
+   2     3.6269e+07  3.1647e-01   1.0432e-01   4       2.9020e+02   3.407
+   3     3.6285e+07  7.6526e-01   1.4596e-04   7       7.5966e+03   5.919
+   4     3.6285e+07  1.1608e-11   2.2270e-01   0       1.5084e-12g  8.823
    ------------------------------------------------------------------------------
    Robust optimal solution identified.
    ------------------------------------------------------------------------------
    Timing breakdown:
-   
+
    Identifier                ncalls   cumtime   percall      %
    -----------------------------------------------------------
-   main                           1     5.281     5.281  100.0
+   main                           1     8.824     8.824  100.0
         ------------------------------------------------------
-        dr_polishing              3     0.155     0.052    2.9
-        global_separation        27     1.280     0.047   24.2
-        local_separation        108     2.200     0.020   41.7
-        master                    4     0.727     0.182   13.8
-        master_feasibility        3     0.103     0.034    1.9
-        preprocessing             1     0.021     0.021    0.4
-        other                   n/a     0.794       n/a   15.0
+        dr_polishing              4     0.547     0.137    6.2
+        global_separation        27     0.978     0.036   11.1
+        local_separation        135     4.645     0.034   52.6
+        master                    5     1.720     0.344   19.5
+        master_feasibility        4     0.239     0.060    2.7
+        preprocessing             1     0.013     0.013    0.2
+        other                   n/a     0.681       n/a    7.7
         ======================================================
    ===========================================================
-   
+
    ------------------------------------------------------------------------------
    Termination stats:
-    Iterations            : 4
-    Solve time (wall s)   : 5.281
+    Iterations            : 5
+    Solve time (wall s)   : 8.824
     Final objective value : 3.6285e+07
     Termination condition : pyrosTerminationCondition.robust_optimal
    ------------------------------------------------------------------------------

pyomo/contrib/pyros/CHANGELOG.txt

@@ -3,6 +3,15 @@ PyROS CHANGELOG
 ===============
 
 
+-------------------------------------------------------------------------------
+PyROS 1.3.9    19 Jul 2025
+-------------------------------------------------------------------------------
+- Update uncertainty set validation methods with efficient, set-specific checks
+- Adjust PyROS handling of separation objective evaluation errors
+- Allow user to configure formats to which PyROS should export subproblems
+  not solved to an acceptable level
+
+
 -------------------------------------------------------------------------------
 PyROS 1.3.8    28 Apr 2025
 -------------------------------------------------------------------------------

pyomo/contrib/pyros/config.py

@@ -855,6 +855,26 @@ def pyros_config():
             ),
         ),
     )
+    CONFIG.declare(
+        "subproblem_format_options",
+        ConfigValue(
+            default={"bar": {"symbolic_solver_labels": True}},
+            # note: we leave all validation of the dict entries
+            #       to ``BlockData.write()``
+            domain=dict,
+            description=(
+                """
+                File format options for writing/exporting subproblems
+                that were not solved to an acceptable level
+                if ``keepfiles=True`` is specified.
+                Each entry of the dict should map a Pyomo WriterFactory
+                format (e.g., 'bar' for BARON, 'gams' for GAMS)
+                to a value for the argument ``io_options``
+                to the method ``BlockData.write()``.
+                """
+            ),
+        ),
+    )
 
     # ================================================
     # === Advanced Options

pyomo/contrib/pyros/master_problem_methods.py

@@ -13,8 +13,6 @@
 Functions for construction and solution of the PyROS master problem.
 """
 
-import os
-
 from pyomo.common.collections import ComponentMap, ComponentSet
 from pyomo.common.modeling import unique_component_name
 from pyomo.core import TransformationFactory
@@ -37,6 +35,7 @@
     ObjectiveType,
     pyrosTerminationCondition,
     TIC_TOC_SOLVE_TIME_ATTR,
+    write_subproblem,
 )
 
 
@@ -828,31 +827,8 @@ def solver_call_master(master_data):
 
     # all solvers have failed to return an acceptable status.
     # we will terminate PyROS with subsolver error status.
-    # at this point, export subproblem to file, if desired.
-    # NOTE: subproblem is written with variables set to their
-    #       initial values (not the final subsolver iterate)
-    save_dir = config.subproblem_file_directory
-    serialization_msg = ""
-    if save_dir and config.keepfiles:
-        output_problem_path = os.path.join(
-            save_dir,
-            (
-                config.uncertainty_set.type
-                + "_"
-                + master_data.original_model_name
-                + "_master_"
-                + str(master_data.iteration)
-                + ".bar"
-            ),
-        )
-        master_model.write(
-            output_problem_path, io_options={'symbolic_solver_labels': True}
-        )
-        serialization_msg = (
-            " For debugging, problem has been serialized to the file "
-            f"{output_problem_path!r}."
-        )
 
+    # log subproblem solve failure warning
     deterministic_model_qual = (
         " (i.e., the deterministic model)" if master_data.iteration == 0 else ""
     )
@@ -867,7 +843,6 @@ def solver_call_master(master_data):
         if master_data.iteration == 0
         else ""
     )
-
     master_soln.pyros_termination_condition = pyrosTerminationCondition.subsolver_error
     subsolver_termination_conditions = [
         res.solver.termination_condition for res in master_soln.master_results_list
@@ -879,9 +854,22 @@ def solver_call_master(master_data):
         f"(Termination statuses: "
         f"{[term_cond for term_cond in subsolver_termination_conditions]}.)"
         f"{deterministic_msg}"
-        f"{serialization_msg}"
     )
 
+    # at this point, export subproblem to file, if desired.
+    # NOTE: subproblem is written with variables set to their
+    #       initial values (not the final subsolver iterate)
+    if config.keepfiles and config.subproblem_file_directory is not None:
+        write_subproblem(
+            model=master_model,
+            fname=(
+                f"{config.uncertainty_set.type}"
+                f"_{master_data.original_model_name}"
+                f"_master_{master_data.iteration}"
+            ),
+            config=config,
+        )
+
     return master_soln
 
 

pyomo/contrib/pyros/pyros.py

@@ -33,7 +33,7 @@
 )
 
 
-__version__ = "1.3.8"
+__version__ = "1.3.9"
 
 
 default_pyros_solver_logger = setup_pyros_logger()

pyomo/contrib/pyros/separation_problem_methods.py

@@ -15,7 +15,6 @@
 """
 
 from itertools import product
-import os
 
 from pyomo.common.collections import ComponentSet, ComponentMap
 from pyomo.common.dependencies import numpy as np
@@ -39,6 +38,7 @@
     call_solver,
     check_time_limit_reached,
     get_all_first_stage_eq_cons,
+    write_subproblem,
 )
 
 
@@ -1093,41 +1093,27 @@ def solver_call_separation(
     # termination condition. PyROS will terminate with subsolver
     # error. At this point, export model if desired
     solve_call_results.subsolver_error = True
-    save_dir = config.subproblem_file_directory
-    serialization_msg = ""
-    if save_dir and config.keepfiles:
-        objective = separation_obj.name
-        output_problem_path = os.path.join(
-            save_dir,
-            (
-                config.uncertainty_set.type
-                + "_"
-                + separation_model.name
-                + "_separation_"
-                + str(separation_data.iteration)
-                + "_obj_"
-                + objective
-                + ".bar"
-            ),
-        )
-        separation_model.write(
-            output_problem_path, io_options={'symbolic_solver_labels': True}
-        )
-        serialization_msg = (
-            " For debugging, problem has been serialized to the file "
-            f"{output_problem_path!r}."
-        )
     solve_call_results.message = (
         "Could not successfully solve separation problem of iteration "
         f"{separation_data.iteration} "
         f"for second-stage inequality constraint {con_name_repr} with any of the "
         f"provided subordinate {solve_mode} optimizers. "
         f"(Termination statuses: "
         f"{[str(term_cond) for term_cond in solver_status_dict.values()]}.)"
-        f"{serialization_msg}"
     )
     config.progress_logger.warning(solve_call_results.message)
 
+    if config.keepfiles and config.subproblem_file_directory is not None:
+        write_subproblem(
+            model=separation_model,
+            fname=(
+                f"{config.uncertainty_set.type}_{separation_model.name}"
+                f"_separation_{separation_data.iteration}"
+                f"_obj_{separation_obj.name}"
+            ),
+            config=config,
+        )
+
     separation_obj.deactivate()
 
     return solve_call_results

pyomo/contrib/pyros/tests/test_config.py

@@ -696,6 +696,38 @@ def test_config_objective_focus(self):
         with self.assertRaisesRegex(ValueError, exc_str):
             config.objective_focus = invalid_focus
 
+    def test_config_subproblem_formats(self):
+        config = self.CONFIG()
+
+        # test default
+        self.assertEqual(
+            config.subproblem_format_options,
+            {"bar": {"symbolic_solver_labels": True}},
+            msg=(
+                "Default value for PyROS config option "
+                "subproblem_format_options' not as expected."
+            ),
+        )
+
+        config.subproblem_format_options = {}
+        self.assertEqual(config.subproblem_format_options, {})
+
+        nondefault_test_val = {"fmt1": {"symbolic_solver_labels": False}, "fmt2": {}}
+        config.subproblem_format_options = nondefault_test_val
+        self.assertEqual(config.subproblem_format_options, nondefault_test_val)
+
+        # anything castable to dict should also be acceptable
+        config.subproblem_format_options = list(nondefault_test_val.items())
+        self.assertEqual(config.subproblem_format_options, nondefault_test_val)
+
+        exc_str = (
+            # contents of the error message are version dependent
+            "(cannot convert dictionary update sequence"
+            "|'int' object is not iterable)"
+        )
+        with self.assertRaisesRegex(ValueError, exc_str):
+            config.subproblem_format_options = [1, 2, 3]
+
 
 class TestPositiveIntOrMinusOne(unittest.TestCase):
     """