try to add mpigap (untested)

mpisppy/agnostic/ampl_guest.py

@@ -66,13 +66,18 @@ def scenario_creator(self, scenario_name, **kwargs):
             scenario_name (str):
                 Name of the scenario to construct.
         """
+        def _has_ints(s):
+            for _,v in s.getVariables():
+                if "binary" in str(v) or "integer" in str(v):
+                    return True
+            return False
+
         s, prob, nonant_vardata_list, obj_fct = self.model_module.scenario_creator(scenario_name,
                                                                      self.ampl_file_name,
                                                                      **kwargs)
         if len(nonant_vardata_list) == 0:
             raise RuntimeError(f"model file {self.model_file_name} has an empty "
                                f" nonant_vardata_list for {scenario_name =}")
-        ### TBD: assert that this is minimization?
         # In general, be sure to process variables in the same order has the guest does (so indexes match)
         nonant_vars = nonant_vardata_list  # typing aid
         def _vname(v):
@@ -86,7 +91,8 @@ def _vname(v):
             "probability": prob,
             "obj_fct": obj_fct,
             "sense": pyo.minimize,
-            "BFs": None
+            "BFs": None,
+            "has_ints": _has_ints(s),
         }
         ##?xxxxx ? create nonant vars and put them on the ampl model,
         ##?xxxxx create constraints to make them equal to the original nonants
@@ -183,6 +189,7 @@ def _vname(i):
         gs.eval("param xbars{nonant_indices};")
         obj_fct = gd["obj_fct"]
         objstr = str(obj_fct)
+        assert objstr.split (' ')[0] == "minimize", "We currently assume minimization"
 
         # Dual term (weights W) (This is where indexes are an issue)
         phobjstr = ""
@@ -274,12 +281,14 @@ def solve_one(self, Ag, s, solve_keyword_args, gripe, tee=False):
 
         # For AMPL mips, we need to use the gap option to compute bounds
         # https://amplmp.readthedocs.io/rst/features-guide.html
+        # As of Aug 2024, this is not tested...
+        mipgap = gs.getValue('_mipgap') if gd["has_ints"] else 0
         objobj = gs.get_current_objective()  # different for xhatters
         objval = objobj.value()
         if gd["sense"] == pyo.minimize:
-            s._mpisppy_data.outer_bound = objval
+            s._mpisppy_data.outer_bound = objval - mipgap
         else:
-            s._mpisppy_data.inner_bound = objval
+            s._mpisppy_data.inner_bound = objval + mpigap
 
         # copy the nonant x values from gs to s so mpisppy can use them in s
         # in general, we need more checks (see the pyomo agnostic guest example)