feat: gently handle unknown status (#409)

* feat: improve log for unknown status, set status to ok if solution could be parsed

* add test for ipm in highspy

Author: FabianHofmann

linopy/common.py

@@ -42,7 +42,7 @@ def set_int_index(series: pd.Series) -> pd.Series:
     """
     Convert string index to int index.
     """
-    if not series.empty and not series.index.is_integer():
+    if not series.empty and not pd.api.types.is_integer_dtype(series.index):
         cutoff = count_initial_letters(str(series.index[0]))
         series.index = series.index.str[cutoff:].astype(int)
     return series

linopy/constants.py

@@ -239,4 +239,4 @@ def info(self) -> None:
             else:
                 logger.info(" Optimization successful: \n%s\n", self)
         else:
-            logger.warning("Optimization failed: \n%s\n", self)
+            logger.warning("Optimization potentially failed: \n%s\n", self)

linopy/solvers.py

@@ -217,9 +217,14 @@ def safe_get_solution(self, status: Status, func: Callable) -> Solution:
         if status.is_ok:
             return func()
         elif status.status == SolverStatus.unknown:
-            with contextlib.suppress(Exception):
+            try:
                 logger.warning("Solution status unknown. Trying to parse solution.")
-                return func()
+                sol = func()
+                status.status = SolverStatus.ok
+                logger.warning("Solution parsed successfully.")
+                return sol
+            except Exception as e:
+                logger.error(f"Failed to parse solution: {e}")
         return Solution()
 
     @abstractmethod

test/test_optimization.py

@@ -410,7 +410,7 @@ def test_default_settings_small_slices(model, solver, io_api):
 
 
 @pytest.mark.parametrize("solver,io_api", params)
-def test_solver_options(model, solver, io_api):
+def test_solver_time_limit_options(model, solver, io_api):
     time_limit_option = {
         "cbc": {"sec": 1},
         "gurobi": {"TimeLimit": 1},
@@ -427,6 +427,17 @@ def test_solver_options(model, solver, io_api):
     assert status == "ok"
 
 
+@pytest.mark.parametrize("solver,io_api", params)
+def test_solver_method_options(model, solver, io_api):
+    method_options = {
+        "highs": {"solver": "ipm", "run_crossover": "off", "parallel": "on"},
+    }
+    if solver in method_options:
+        status, condition = model.solve(solver, io_api=io_api, **method_options[solver])
+        assert status == "ok"
+        assert np.isclose(model.objective.value, 3.3)
+
+
 @pytest.mark.parametrize("solver,io_api", params)
 def test_duplicated_variables(model_with_duplicated_variables, solver, io_api):
     status, condition = model_with_duplicated_variables.solve(solver, io_api=io_api)